smb-psexec
NSE detection rule by Ron Bowes · Same as Nmap--See https://nmap.org/book/man-legal.html
Implements remote process execution similar to the Sysinternals' psexec
tool, allowing a user to run a series of programs on a remote machine and
read the output. This is great for gathering information about servers,
running the same tool on a range of system, or even installing a backdoor on
a collection of computers.
This script can run commands present on the remote machine, such as ping or
tracert, or it can upload a program and run it, such as pwdump6 or a
backdoor. Additionally, it can read the program's stdout/stderr and return
it to the user (works well with ping, pwdump6, etc), or it can read a file
that the process generated (fgdump, for example, generates a file), or it
can just start the process and let it run headless (a backdoor might run
like this).
To use this, a configuration file should be created and edited. Several
configuration files are included that you can customize, or you can write
your own. This config file is placed in <code>nselib/data/psexec</code> (if
you aren't sure where that is, search your system for
<code>default.lua</code>), then is passed to Nmap as a script argument (for
example, myconfig.lua would be passed as
<code>--script-args=config=myconfig</code>.
The configuration file consists mainly of a module list. Each module is
defined by a lua table, and contains fields for the name of the program, the
executable and arguments for the program, and a score of other options.
Modules also have an 'upload' field, which determines whether or not the
module is to be uploaded. Here is a simple example of how to run <code>net
localgroup administrators</code>, which returns a list of users in the
"administrators" group (take a look at the <code>examples.lua</code>
configuration file for these examples):
<code>
mod = {}
mod.upload = false
mod.name = "Example 1: Membership of 'administrators'"
mod.program = "net.exe"
mod.args = "localgroup administrators"
table.insert(modules, mod)
</code>
<code>mod.upload</code> is <code>false</code>, meaning the program should
already be present on the remote system (since 'net.exe' is on every version
of Windows, this should be the case). <code>mod.name</code> defines the name
that the program will have in the output. <code>mod.program</code> and
<code>mod.args</code> obviously define which program is going to be run. The
output for this script is this:
<code>
| Example 1: Membership of 'administrators'
| | Alias name administrators
| | Comment Administrators have complete and unrestricted access to the computer/domain
| |
| | Members
| |
| | -------------------------------------------------------------------------------
| | Administrator
| | ron
| | test
| | The command completed successfully.
| |
| |_
</code>
That works, but it's really ugly. In general, we can use
<code>mod.find</code>, <code>mod.replace</code>, <code>mod.remove</code>,
and <code>mod.noblank</code> to clean up the output. For this example, we're
going to use <code>mod.remove</code> to remove a lot of the useless lines,
and <code>mod.noblank</code> to get rid of the blank lines that we don't
want:
<code>
mod = {}
mod.upload = false
mod.name = "Example 2: Membership of 'administrators', cleaned"
mod.program = "net.exe"
mod.args = "localgroup administrators"
mod.remove = {"The command completed", "%-%-%-%-%-%-%-%-%-%-%-", "Members", "Alias name", "Comment"}
mod.noblank = true
table.insert(modules, mod)
</code>
We can see that the output is now much cleaner:
<code>
| Example 2: Membership of 'administrators', cleaned
| | Administrator
| | ron
| |_test
</code>
For our next command, we're going to run Windows' ipconfig.exe, which
outputs a significant amount of unnecessary information, and what we do want
isn't formatted very nicely. All we want is the IP address and MAC address,
and we get it using <code>mod.find</code> and <code>mod.replace</code>:
<code>
mod = {}
mod.upload = false
mod.name = "Example 3: IP Address and MAC Address"
mod.program = "ipconfig.exe"
mod.args = "/all"
mod.maxtime = 1
mod.find = {"IP Address", "Physical Address", "Ethernet adapter"}
mod.replace = {{"%. ", ""}, {"-", ":"}, {"Physical Address", "MAC Address"}}
table.insert(modules, mod)
</code>
This module searches for lines that contain "IP Address", "Physical
Address", or "Ethernet adapter". In these lines, a ". " is replaced with
nothing, a "-" is replaced with a colon, and the term "Physical Address" is
replaced with "MAC Address" (arguably unnecessary). Run ipconfig /all
yourself to see what we start with, but here's the final output:
<code>
| Example 3: IP Address and MAC Address
| | Ethernet adapter Local Area Connection:
| | MAC Address: 00:0C:29:12:E6:DB
| |_ IP Address: 192.168.1.21| Example 3: IP Address and MAC Address
</code>
Another interesting part of this script is that variables can be used in any
script fields. There are two types of variables: built-in and user-supplied.
Built-in variables can be anything found in the <code>config</code> table,
most of which are listed below. The more interesting ones are:
* <code>$lhost</code>: The address of the scanner
* <code>$rhost</code>: The address being scanned
* <code>$path</code>: The path where the scripts are uploaded
* <code>$share</code>: The share where the script was uploaded
User-supplied arguments are given on the commandline, and can be controlled
by <code>mod.req_args</code> in the configuration file. Arguments are given
by the user in --script-args; for example, to set $host to '1.2.3.4', the
user would pass in --script-args=host=1.2.3.4. To ensure the user passes in
the host variable, <code>mod.req_args</code> would be set to
<code>{'host'}</code>.
Here is a module that pings the local ip address:
<code>
mod = {}
mod.upload = false
mod.name = "Example 4: Can the host ping our address?"
mod.program = "ping.exe"
mod.args = "$lhost"
mod.remove = {"statistics", "Packet", "Approximate", "Minimum"}
mod.noblank = true
mod.env = "SystemRoot=c:\\WINDOWS"
table.insert(modules, mod)
</code>
And the output:
<code>
| Example 4: Can the host ping our address?
| | Pinging 192.168.1.100 with 32 bytes of data:
| | Reply from 192.168.1.100: bytes=32 time<1ms TTL=64
| | Reply from 192.168.1.100: bytes=32 time<1ms TTL=64
| | Reply from 192.168.1.100: bytes=32 time<1ms TTL=64
| |_Reply from 192.168.1.100: bytes=32 time<1ms TTL=64
</code>
And this module pings an arbitrary address that the user is expected to
give:
<code>
mod = {}
mod.upload = false
mod.name = "Example 5: Can the host ping $host?"
mod.program = "ping.exe"
mod.args = "$host"
mod.remove = {"statistics", "Packet", "Approximate", "Minimum"}
mod.noblank = true
mod.env = "SystemRoot=c:\\WINDOWS"
mod.req_args = {'host'}
table.insert(modules, mod)
</code>
And the output (note that we had to up the timeout so this would complete;
we'll talk about override values later):
<code>
$ ./nmap -n -d -p445 --script=smb-psexec --script-args=smbuser=test,smbpass=test,config=examples,host=1.2.3.4 192.168.1.21
[...]
| Example 5: Can the host ping 1.2.3.4?
| | Pinging 1.2.3.4 with 32 bytes of data:
| | Request timed out.
| | Request timed out.
| | Request timed out.
| |_Request timed out.
</code>
For the final example, we'll use the <code>upload</code> command to upload
<code>fgdump.exe</code>, run it, download its output file, and clean up its
logfile. You'll have to put <code>fgdump.exe</code> in the same folder as
the script for this to work:
<code>
mod = {}
mod.upload = true
mod.name = "Example 6: FgDump"
mod.program = "fgdump.exe"
mod.args = "-c -l fgdump.log"
mod.url = "http://www.foofus.net/fizzgig/fgdump/"
mod.tempfiles = {"fgdump.log"}
mod.outfile = "127.0.0.1.pwdump"
table.insert(modules, mod)
</code>
The <code>-l</code> argument for fgdump supplies the name of the logfile.
That file is listed in the <code>mod.tempfiles</code> field. What, exactly,
does <code>mod.tempfiles</code> do? It simply gives the service a list of
files to delete while cleaning up. The cleanup process will be discussed
later.
<code>mod.url</code> is displayed to the user if <code>mod.program</code>
isn't found in <code>nselib/data/psexec/</code>. And finally,
<code>mod.outfile</code> is the file that is downloaded from the system.
This is required because fgdump writes to an output file instead of to
stdout (pwdump6, for example, doesn't require <code>mod.outfile</code>.
Now that we've seen a few possible combinations of fields, I present a
complete list of all fields available and what each of them do. Many of them
will be familiar, but there are a few that aren't discussed in the examples:
* <code>upload</code> (boolean) true if it's a local file to upload, false
if it's already on the host machine. If
<code>upload</code> is true, <code>program</code> has
to be in <code>nselib/data/psexec</code>.
* <code>name</code> (string) The name to display above the output. If this
isn't given, <code>program</code> .. <code>args</code>
are used.
* <code>program</code> (string) If <code>upload</code> is false, the name
(fully qualified or relative) of the program on the
remote system; if <code>upload</code> is true, the
name of the local file that will be uploaded (stored
in <code>nselib/data/psexec</code>).
* <code>args</code> (string) Arguments to pass to the process.
* <code>env</code> (string) Environmental variables to pass to the process,
as name=value pairs, delimited, per Microsoft's spec, by
NULL characters (<code>string.char(0)</code>).
* <code>maxtime</code> (integer) The approximate amount of time to wait for
this process to complete. The total timeout for the
script before it gives up waiting for a response is
the total of all <code>maxtime</code> fields.
* <code>extrafiles</code> (string[]) Extra file(s) to upload before running
the program. These will not be renamed (because,
presumably, if they are then the program won't be
able to find them), but they will be marked as
hidden/system/etc. This may cause a race condition
if multiple people are doing this at once, but
there isn't much we can do. The files are also
deleted afterwards as tempfiles would be. The
files have to be in the same directory as programs
(<code>nselib/data/psexec</code>), but the program
doesn't necessarily need to be an uploaded one.
* <code>tempfiles</code> (string[]) A list of temporary files that the
process is known to create (if the process does
create files, using this field is recommended
because it helps avoid making a mess on the remote
system).
* <code>find</code> (string[]) Only display lines that contain the given
string(s) (for example, if you're searching for a line
that contains "IP Address", set this to <code>{'IP
Address'}</code>. This allows Lua-style patterns, see:
http://lua-users.org/wiki/PatternsTutorial (don't forget
to escape special characters with a <code>%</code>).
Note that this is client-side only; the full output is
still returned, the rest is removed while displaying.
The line of output only needs to match one of the
strings given here.
* <code>remove</code> (string[]) Opposite of <code>find</code>; this removes
lines containing the given string(s) instead of
displaying them. Like <code>find</code>, this is
client-side only and uses Lua-style patterns. If
<code>remove</code> and <code>find</code> are in
conflict, then <code>remove</code> takes priority.
* <code>noblank</code> (boolean) Setting this to true removes all blank
lines from the output.
* <code>replace</code> (table) A table of values to replace in the strings
returned. Like <code>find</code> and
<code>replace</code>, this is client-side only and
uses Lua-style patterns.
* <code>headless</code> (boolean) If <code>headless</code> is set to true,
the program doesn't return any output; rather, it
runs detached from the service so that, when the
service ends, the program keeps going. This can be
useful for, say, a monitoring program. Or a
backdoor, if that's what you're into (a Metasploit
payload should work nicely). Not compatible with:
<code>find</code>, <code>remove</code>,
<code>noblank</code>, <code>replace</code>,
<code>maxtime</code>, <code>outfile</code>.
* <code>enabled</code> (boolean) Set to false, and optionally set
<code>disabled_message</code>, if you don't want a
module to run. Alternatively, you can comment out
the process.
* <code>disabled_message</code> (string) Displayed if the module is disabled.
* <code>url</code> (string) A module where the user can download the
uploadable file. Displayed if the uploadable file is
missing.
* <code>outfile</code> (string) If set, the specified file will be returned
instead of stdout.
* <code>req_args</code> (string[]) An array of arguments that the user must
set in <code>--script-args</code>.
Any field in the configuration file can contain variables, as discussed.
Here are some of the available built-in variables:
* <code>$lhost</code>: local IP address as a string.
* <code>$lport</code>: local port (meaningless; it'll change by the time the
module is uploaded since multiple connections are
made).
* <code>$rhost</code>: remote IP address as a string.
* <code>$rport</code>: remote port.
* <code>$lmac</code>: local MAC address as a string in the
xx:xx:xx:xx:xx:xx format (note: requires root).
* <code>$path</code>: the path where the file will be uploaded to.
* <code>$service_name</code>: the name of the service that will be running
this program
* <code>$service_file</code>: the name of the executable file for the
service
* <code>$temp_output_file</code>: The (ciphered) file where the programs'
output will be written before being
renamed to $output_file
* <code>$output_file</code>: The final name of the (ciphered) output file.
When this file appears, the script downloads it
and stops the service
* <code>$timeout</code>: The total amount of time the script is going to run
before it gives up and stops the process
* <code>$share</code>: The share that everything was uploaded to
* (script args): Any value passed as a script argument will be replaced (for
example, if Nmap is run with
<code>--script-args=var3=10</code>, then <code>$var3</code>
in any field will be replaced with <code>10</code>. See the
<code>req_args</code> field above. Script argument values
take priority over config values.
In addition to modules, the configuration file can also contain overrides.
Most of these aren't useful, so I'm not going to go into great detail.
Search <code>smb-psexec.nse</code> for any reference to the
<code>config</code> table; any value in the <code>config</code> table can be
overridden with the <code>overrides</code> table in the module. The most
useful value to override is probably <code>timeout</code>.
Before and after scripts are run, and when there's an error, a cleanup is
performed. in the cleanup, we attempt to stop the remote processes, delete
all programs, output files, temporary files, extra files, etc. A lot of
effort was put into proper cleanup, since making a mess on remote systems is
a bad idea.
Now that I've talked at length about how to use this script, I'd like to
spend some time talking about how it works.
Running a script happens in several stages:
1. An open fileshare is found that we can write to. Finding an open
fileshare basically consists of enumerating all shares and seeing which
one(s) we have access to.
2. A "service wrapper", and all of the uploadable/extra files, are uploaded.
Before they're uploaded, the name of each file is obfuscated. The
obfuscation completely renames the file, is unique for each source system,
and doesn't change between multiple runs. This obfuscation has the benefit
of preventing filenames from overlapping if multiple people are running this
against the same computer, and also makes it more difficult to determine
their purposes. The reason for keeping them consistent for every run is to
make cleanup possible: a random filename, if the script somehow fails, will
be left on the system.
3. A new service is created and started. The new service has a random name
for the same reason the files do, and points at the 'service wrapper'
program that was uploaded.
4. The service runs the processes. One by one, the processes are run and
their output is captured. The output is obfuscated using a simple (and
highly insecure) xor algorithm, which is designed to prevent casual sniffing
(but won't deter intelligent attackers). This data is put into a temporary
output file. When all the programs have finished, the file is renamed to the
final output file
5. The output file is downloaded, and the cleanup is performced. The file
being renamed triggers the final stage of the program, where the data is
downloaded and all relevant files are deleted.
6. Output file, now decrypted, is formatted and displayed to the user.
And that's how it works!
Please post any questions, or suggestions for better modules, to
dev@nmap.org.
And, as usual, since this tool can be dangerous and can easily be viewed as
a malicious tool -- use this responsibly, and don't break any laws with it.
Some ideas for later versions (TODO):
* Set up a better environment for scripts (<code>PATH</code>,
<code>SystemRoot</code>, etc). Without this, a lot of programs (especially
ones that deal with network traffic) behave oddly.
* Abstract the code required to run remote processes so other scripts can
use it more easily (difficult, but will ultimately be well worth it
later). (May actually not be possible. There is a lot of overhead and
specialized code in this module. We'll see, though.)
* Let user specify an output file (per-script) so they can, for example,
download binary files (don't think it's worthwhile).
* Consider running the external programs in parallel (not sure if the
benefits outweigh the drawbacks).
* Let the config request the return code from the process instead of the
output (not sure if doing this would be worth the effort).
* Check multiple shares in a single session to save packets (and see where
else we can tighten up the amount of traffic).
local _G = require "_G"
local io = require "io"
local math = require "math"
local msrpc = require "msrpc"
local nmap = require "nmap"
local smb = require "smb"
local stdnse = require "stdnse"
local string = require "string"
local stringaux = require "stringaux"
local table = require "table"
description = [[
Implements remote process execution similar to the Sysinternals' psexec
tool, allowing a user to run a series of programs on a remote machine and
read the output. This is great for gathering information about servers,
running the same tool on a range of system, or even installing a backdoor on
a collection of computers.
This script can run commands present on the remote machine, such as ping or
tracert, or it can upload a program and run it, such as pwdump6 or a
backdoor. Additionally, it can read the program's stdout/stderr and return
it to the user (works well with ping, pwdump6, etc), or it can read a file
that the process generated (fgdump, for example, generates a file), or it
can just start the process and let it run headless (a backdoor might run
like this).
To use this, a configuration file should be created and edited. Several
configuration files are included that you can customize, or you can write
your own. This config file is placed in <code>nselib/data/psexec</code> (if
you aren't sure where that is, search your system for
<code>default.lua</code>), then is passed to Nmap as a script argument (for
example, myconfig.lua would be passed as
<code>--script-args=config=myconfig</code>.
The configuration file consists mainly of a module list. Each module is
defined by a lua table, and contains fields for the name of the program, the
executable and arguments for the program, and a score of other options.
Modules also have an 'upload' field, which determines whether or not the
module is to be uploaded. Here is a simple example of how to run <code>net
localgroup administrators</code>, which returns a list of users in the
"administrators" group (take a look at the <code>examples.lua</code>
configuration file for these examples):
<code>
mod = {}
mod.upload = false
mod.name = "Example 1: Membership of 'administrators'"
mod.program = "net.exe"
mod.args = "localgroup administrators"
table.insert(modules, mod)
</code>
<code>mod.upload</code> is <code>false</code>, meaning the program should
already be present on the remote system (since 'net.exe' is on every version
of Windows, this should be the case). <code>mod.name</code> defines the name
that the program will have in the output. <code>mod.program</code> and
<code>mod.args</code> obviously define which program is going to be run. The
output for this script is this:
<code>
| Example 1: Membership of 'administrators'
| | Alias name administrators
| | Comment Administrators have complete and unrestricted access to the computer/domain
| |
| | Members
| |
| | -------------------------------------------------------------------------------
| | Administrator
| | ron
| | test
| | The command completed successfully.
| |
| |_
</code>
That works, but it's really ugly. In general, we can use
<code>mod.find</code>, <code>mod.replace</code>, <code>mod.remove</code>,
and <code>mod.noblank</code> to clean up the output. For this example, we're
going to use <code>mod.remove</code> to remove a lot of the useless lines,
and <code>mod.noblank</code> to get rid of the blank lines that we don't
want:
<code>
mod = {}
mod.upload = false
mod.name = "Example 2: Membership of 'administrators', cleaned"
mod.program = "net.exe"
mod.args = "localgroup administrators"
mod.remove = {"The command completed", "%-%-%-%-%-%-%-%-%-%-%-", "Members", "Alias name", "Comment"}
mod.noblank = true
table.insert(modules, mod)
</code>
We can see that the output is now much cleaner:
<code>
| Example 2: Membership of 'administrators', cleaned
| | Administrator
| | ron
| |_test
</code>
For our next command, we're going to run Windows' ipconfig.exe, which
outputs a significant amount of unnecessary information, and what we do want
isn't formatted very nicely. All we want is the IP address and MAC address,
and we get it using <code>mod.find</code> and <code>mod.replace</code>:
<code>
mod = {}
mod.upload = false
mod.name = "Example 3: IP Address and MAC Address"
mod.program = "ipconfig.exe"
mod.args = "/all"
mod.maxtime = 1
mod.find = {"IP Address", "Physical Address", "Ethernet adapter"}
mod.replace = {{"%. ", ""}, {"-", ":"}, {"Physical Address", "MAC Address"}}
table.insert(modules, mod)
</code>
This module searches for lines that contain "IP Address", "Physical
Address", or "Ethernet adapter". In these lines, a ". " is replaced with
nothing, a "-" is replaced with a colon, and the term "Physical Address" is
replaced with "MAC Address" (arguably unnecessary). Run ipconfig /all
yourself to see what we start with, but here's the final output:
<code>
| Example 3: IP Address and MAC Address
| | Ethernet adapter Local Area Connection:
| | MAC Address: 00:0C:29:12:E6:DB
| |_ IP Address: 192.168.1.21| Example 3: IP Address and MAC Address
</code>
Another interesting part of this script is that variables can be used in any
script fields. There are two types of variables: built-in and user-supplied.
Built-in variables can be anything found in the <code>config</code> table,
most of which are listed below. The more interesting ones are:
* <code>$lhost</code>: The address of the scanner
* <code>$rhost</code>: The address being scanned
* <code>$path</code>: The path where the scripts are uploaded
* <code>$share</code>: The share where the script was uploaded
User-supplied arguments are given on the commandline, and can be controlled
by <code>mod.req_args</code> in the configuration file. Arguments are given
by the user in --script-args; for example, to set $host to '1.2.3.4', the
user would pass in --script-args=host=1.2.3.4. To ensure the user passes in
the host variable, <code>mod.req_args</code> would be set to
<code>{'host'}</code>.
Here is a module that pings the local ip address:
<code>
mod = {}
mod.upload = false
mod.name = "Example 4: Can the host ping our address?"
mod.program = "ping.exe"
mod.args = "$lhost"
mod.remove = {"statistics", "Packet", "Approximate", "Minimum"}
mod.noblank = true
mod.env = "SystemRoot=c:\\WINDOWS"
table.insert(modules, mod)
</code>
And the output:
<code>
| Example 4: Can the host ping our address?
| | Pinging 192.168.1.100 with 32 bytes of data:
| | Reply from 192.168.1.100: bytes=32 time<1ms TTL=64
| | Reply from 192.168.1.100: bytes=32 time<1ms TTL=64
| | Reply from 192.168.1.100: bytes=32 time<1ms TTL=64
| |_Reply from 192.168.1.100: bytes=32 time<1ms TTL=64
</code>
And this module pings an arbitrary address that the user is expected to
give:
<code>
mod = {}
mod.upload = false
mod.name = "Example 5: Can the host ping $host?"
mod.program = "ping.exe"
mod.args = "$host"
mod.remove = {"statistics", "Packet", "Approximate", "Minimum"}
mod.noblank = true
mod.env = "SystemRoot=c:\\WINDOWS"
mod.req_args = {'host'}
table.insert(modules, mod)
</code>
And the output (note that we had to up the timeout so this would complete;
we'll talk about override values later):
<code>
$ ./nmap -n -d -p445 --script=smb-psexec --script-args=smbuser=test,smbpass=test,config=examples,host=1.2.3.4 192.168.1.21
[...]
| Example 5: Can the host ping 1.2.3.4?
| | Pinging 1.2.3.4 with 32 bytes of data:
| | Request timed out.
| | Request timed out.
| | Request timed out.
| |_Request timed out.
</code>
For the final example, we'll use the <code>upload</code> command to upload
<code>fgdump.exe</code>, run it, download its output file, and clean up its
logfile. You'll have to put <code>fgdump.exe</code> in the same folder as
the script for this to work:
<code>
mod = {}
mod.upload = true
mod.name = "Example 6: FgDump"
mod.program = "fgdump.exe"
mod.args = "-c -l fgdump.log"
mod.url = "http://www.foofus.net/fizzgig/fgdump/"
mod.tempfiles = {"fgdump.log"}
mod.outfile = "127.0.0.1.pwdump"
table.insert(modules, mod)
</code>
The <code>-l</code> argument for fgdump supplies the name of the logfile.
That file is listed in the <code>mod.tempfiles</code> field. What, exactly,
does <code>mod.tempfiles</code> do? It simply gives the service a list of
files to delete while cleaning up. The cleanup process will be discussed
later.
<code>mod.url</code> is displayed to the user if <code>mod.program</code>
isn't found in <code>nselib/data/psexec/</code>. And finally,
<code>mod.outfile</code> is the file that is downloaded from the system.
This is required because fgdump writes to an output file instead of to
stdout (pwdump6, for example, doesn't require <code>mod.outfile</code>.
Now that we've seen a few possible combinations of fields, I present a
complete list of all fields available and what each of them do. Many of them
will be familiar, but there are a few that aren't discussed in the examples:
* <code>upload</code> (boolean) true if it's a local file to upload, false
if it's already on the host machine. If
<code>upload</code> is true, <code>program</code> has
to be in <code>nselib/data/psexec</code>.
* <code>name</code> (string) The name to display above the output. If this
isn't given, <code>program</code> .. <code>args</code>
are used.
* <code>program</code> (string) If <code>upload</code> is false, the name
(fully qualified or relative) of the program on the
remote system; if <code>upload</code> is true, the
name of the local file that will be uploaded (stored
in <code>nselib/data/psexec</code>).
* <code>args</code> (string) Arguments to pass to the process.
* <code>env</code> (string) Environmental variables to pass to the process,
as name=value pairs, delimited, per Microsoft's spec, by
NULL characters (<code>string.char(0)</code>).
* <code>maxtime</code> (integer) The approximate amount of time to wait for
this process to complete. The total timeout for the
script before it gives up waiting for a response is
the total of all <code>maxtime</code> fields.
* <code>extrafiles</code> (string[]) Extra file(s) to upload before running
the program. These will not be renamed (because,
presumably, if they are then the program won't be
able to find them), but they will be marked as
hidden/system/etc. This may cause a race condition
if multiple people are doing this at once, but
there isn't much we can do. The files are also
deleted afterwards as tempfiles would be. The
files have to be in the same directory as programs
(<code>nselib/data/psexec</code>), but the program
doesn't necessarily need to be an uploaded one.
* <code>tempfiles</code> (string[]) A list of temporary files that the
process is known to create (if the process does
create files, using this field is recommended
because it helps avoid making a mess on the remote
system).
* <code>find</code> (string[]) Only display lines that contain the given
string(s) (for example, if you're searching for a line
that contains "IP Address", set this to <code>{'IP
Address'}</code>. This allows Lua-style patterns, see:
http://lua-users.org/wiki/PatternsTutorial (don't forget
to escape special characters with a <code>%</code>).
Note that this is client-side only; the full output is
still returned, the rest is removed while displaying.
The line of output only needs to match one of the
strings given here.
* <code>remove</code> (string[]) Opposite of <code>find</code>; this removes
lines containing the given string(s) instead of
displaying them. Like <code>find</code>, this is
client-side only and uses Lua-style patterns. If
<code>remove</code> and <code>find</code> are in
conflict, then <code>remove</code> takes priority.
* <code>noblank</code> (boolean) Setting this to true removes all blank
lines from the output.
* <code>replace</code> (table) A table of values to replace in the strings
returned. Like <code>find</code> and
<code>replace</code>, this is client-side only and
uses Lua-style patterns.
* <code>headless</code> (boolean) If <code>headless</code> is set to true,
the program doesn't return any output; rather, it
runs detached from the service so that, when the
service ends, the program keeps going. This can be
useful for, say, a monitoring program. Or a
backdoor, if that's what you're into (a Metasploit
payload should work nicely). Not compatible with:
<code>find</code>, <code>remove</code>,
<code>noblank</code>, <code>replace</code>,
<code>maxtime</code>, <code>outfile</code>.
* <code>enabled</code> (boolean) Set to false, and optionally set
<code>disabled_message</code>, if you don't want a
module to run. Alternatively, you can comment out
the process.
* <code>disabled_message</code> (string) Displayed if the module is disabled.
* <code>url</code> (string) A module where the user can download the
uploadable file. Displayed if the uploadable file is
missing.
* <code>outfile</code> (string) If set, the specified file will be returned
instead of stdout.
* <code>req_args</code> (string[]) An array of arguments that the user must
set in <code>--script-args</code>.
Any field in the configuration file can contain variables, as discussed.
Here are some of the available built-in variables:
* <code>$lhost</code>: local IP address as a string.
* <code>$lport</code>: local port (meaningless; it'll change by the time the
module is uploaded since multiple connections are
made).
* <code>$rhost</code>: remote IP address as a string.
* <code>$rport</code>: remote port.
* <code>$lmac</code>: local MAC address as a string in the
xx:xx:xx:xx:xx:xx format (note: requires root).
* <code>$path</code>: the path where the file will be uploaded to.
* <code>$service_name</code>: the name of the service that will be running
this program
* <code>$service_file</code>: the name of the executable file for the
service
* <code>$temp_output_file</code>: The (ciphered) file where the programs'
output will be written before being
renamed to $output_file
* <code>$output_file</code>: The final name of the (ciphered) output file.
When this file appears, the script downloads it
and stops the service
* <code>$timeout</code>: The total amount of time the script is going to run
before it gives up and stops the process
* <code>$share</code>: The share that everything was uploaded to
* (script args): Any value passed as a script argument will be replaced (for
example, if Nmap is run with
<code>--script-args=var3=10</code>, then <code>$var3</code>
in any field will be replaced with <code>10</code>. See the
<code>req_args</code> field above. Script argument values
take priority over config values.
In addition to modules, the configuration file can also contain overrides.
Most of these aren't useful, so I'm not going to go into great detail.
Search <code>smb-psexec.nse</code> for any reference to the
<code>config</code> table; any value in the <code>config</code> table can be
overridden with the <code>overrides</code> table in the module. The most
useful value to override is probably <code>timeout</code>.
Before and after scripts are run, and when there's an error, a cleanup is
performed. in the cleanup, we attempt to stop the remote processes, delete
all programs, output files, temporary files, extra files, etc. A lot of
effort was put into proper cleanup, since making a mess on remote systems is
a bad idea.
Now that I've talked at length about how to use this script, I'd like to
spend some time talking about how it works.
Running a script happens in several stages:
1. An open fileshare is found that we can write to. Finding an open
fileshare basically consists of enumerating all shares and seeing which
one(s) we have access to.
2. A "service wrapper", and all of the uploadable/extra files, are uploaded.
Before they're uploaded, the name of each file is obfuscated. The
obfuscation completely renames the file, is unique for each source system,
and doesn't change between multiple runs. This obfuscation has the benefit
of preventing filenames from overlapping if multiple people are running this
against the same computer, and also makes it more difficult to determine
their purposes. The reason for keeping them consistent for every run is to
make cleanup possible: a random filename, if the script somehow fails, will
be left on the system.
3. A new service is created and started. The new service has a random name
for the same reason the files do, and points at the 'service wrapper'
program that was uploaded.
4. The service runs the processes. One by one, the processes are run and
their output is captured. The output is obfuscated using a simple (and
highly insecure) xor algorithm, which is designed to prevent casual sniffing
(but won't deter intelligent attackers). This data is put into a temporary
output file. When all the programs have finished, the file is renamed to the
final output file
5. The output file is downloaded, and the cleanup is performced. The file
being renamed triggers the final stage of the program, where the data is
downloaded and all relevant files are deleted.
6. Output file, now decrypted, is formatted and displayed to the user.
And that's how it works!
Please post any questions, or suggestions for better modules, to
dev@nmap.org.
And, as usual, since this tool can be dangerous and can easily be viewed as
a malicious tool -- use this responsibly, and don't break any laws with it.
Some ideas for later versions (TODO):
* Set up a better environment for scripts (<code>PATH</code>,
<code>SystemRoot</code>, etc). Without this, a lot of programs (especially
ones that deal with network traffic) behave oddly.
* Abstract the code required to run remote processes so other scripts can
use it more easily (difficult, but will ultimately be well worth it
later). (May actually not be possible. There is a lot of overhead and
specialized code in this module. We'll see, though.)
* Let user specify an output file (per-script) so they can, for example,
download binary files (don't think it's worthwhile).
* Consider running the external programs in parallel (not sure if the
benefits outweigh the drawbacks).
* Let the config request the return code from the process instead of the
output (not sure if doing this would be worth the effort).
* Check multiple shares in a single session to save packets (and see where
else we can tighten up the amount of traffic).
]]
---
-- @usage
-- nmap --script smb-psexec.nse --script-args=smbuser=<username>,smbpass=<password>[,config=<config>] -p445 <host>
-- sudo nmap -sU -sS --script smb-psexec.nse --script-args=smbuser=<username>,smbpass=<password>[,config=<config>] -p U:137,T:139 <host>
--
-- @output
-- Host script results:
-- | smb-psexec:
-- | | Windows version
-- | | |_ Microsoft Windows 2000 [Version 5.00.2195]
-- | | IP Address and MAC Address from 'ipconfig.exe'
-- | | | Ethernet adapter Local Area Connection 2:
-- | | | MAC Address: 00:50:56:A1:24:C2
-- | | | IP Address: 10.0.0.30
-- | | | Ethernet adapter Local Area Connection:
-- | | |_ MAC Address: 00:50:56:A1:00:65
-- | | User list from 'net user'
-- | | | Administrator TestUser3 Guest
-- | | | IUSR_RON-WIN2K-TEST IWAM_RON-WIN2K-TEST nmap
-- | | | rontest123 sshd SvcCOPSSH
-- | | |_ test1234 Testing TsInternetUser
-- | | Membership of 'administrators' from 'net localgroup administrators'
-- | | | Administrator
-- | | | SvcCOPSSH
-- | | | test1234
-- | | |_ Testing
-- | | Can the host ping our address?
-- | | | Pinging 10.0.0.138 with 32 bytes of data:
-- | | |_ Reply from 10.0.0.138: bytes=32 time<10ms TTL=64
-- | | Traceroute back to the scanner
-- | | |_ 1 <10 ms <10 ms <10 ms 10.0.0.138
-- | | ARP Cache from arp.exe
-- | | | Internet Address Physical Address Type
-- | | |_ 10.0.0.138 00-50-56-a1-27-4b dynamic
-- | | List of listening and established connections (netstat -an)
-- | | | Proto Local Address Foreign Address State
-- | | | TCP 0.0.0.0:22 0.0.0.0:0 LISTENING
-- | | | TCP 0.0.0.0:25 0.0.0.0:0 LISTENING
-- | | | TCP 0.0.0.0:80 0.0.0.0:0 LISTENING
-- | | | TCP 0.0.0.0:135 0.0.0.0:0 LISTENING
-- | | | TCP 0.0.0.0:443 0.0.0.0:0 LISTENING
-- | | | TCP 0.0.0.0:445 0.0.0.0:0 LISTENING
-- | | | TCP 0.0.0.0:1025 0.0.0.0:0 LISTENING
-- | | | TCP 0.0.0.0:1028 0.0.0.0:0 LISTENING
-- | | | TCP 0.0.0.0:1029 0.0.0.0:0 LISTENING
-- | | | TCP 0.0.0.0:3389 0.0.0.0:0 LISTENING
-- | | | TCP 0.0.0.0:4933 0.0.0.0:0 LISTENING
-- | | | TCP 10.0.0.30:139 0.0.0.0:0 LISTENING
-- | | | TCP 127.0.0.1:2528 127.0.0.1:2529 ESTABLISHED
-- | | | TCP 127.0.0.1:2529 127.0.0.1:2528 ESTABLISHED
-- | | | TCP 127.0.0.1:2531 127.0.0.1:2532 ESTABLISHED
-- | | | TCP 127.0.0.1:2532 127.0.0.1:2531 ESTABLISHED
-- | | | TCP 127.0.0.1:5152 0.0.0.0:0 LISTENING
-- | | | TCP 127.0.0.1:5152 127.0.0.1:2530 CLOSE_WAIT
-- | | | UDP 0.0.0.0:135 *:*
-- | | | UDP 0.0.0.0:445 *:*
-- | | | UDP 0.0.0.0:1030 *:*
-- | | | UDP 0.0.0.0:3456 *:*
-- | | | UDP 10.0.0.30:137 *:*
-- | | | UDP 10.0.0.30:138 *:*
-- | | | UDP 10.0.0.30:500 *:*
-- | | | UDP 10.0.0.30:4500 *:*
-- | | |_ UDP 127.0.0.1:1026 *:*
-- | | Full routing table from 'netstat -nr'
-- | | | ===========================================================================
-- | | | Interface List
-- | | | 0x1 ........................... MS TCP Loopback interface
-- | | | 0x2 ...00 50 56 a1 00 65 ...... VMware Accelerated AMD PCNet Adapter
-- | | | 0x1000004 ...00 50 56 a1 24 c2 ...... VMware Accelerated AMD PCNet Adapter
-- | | | ===========================================================================
-- | | | ===========================================================================
-- | | | Active Routes:
-- | | | Network Destination Netmask Gateway Interface Metric
-- | | | 10.0.0.0 255.255.255.0 10.0.0.30 10.0.0.30 1
-- | | | 10.0.0.30 255.255.255.255 127.0.0.1 127.0.0.1 1
-- | | | 10.255.255.255 255.255.255.255 10.0.0.30 10.0.0.30 1
-- | | | 127.0.0.0 255.0.0.0 127.0.0.1 127.0.0.1 1
-- | | | 224.0.0.0 224.0.0.0 10.0.0.30 10.0.0.30 1
-- | | | 255.255.255.255 255.255.255.255 10.0.0.30 2 1
-- | | | ===========================================================================
-- | | | Persistent Routes:
-- | | | None
-- |_ |_ |_ Route Table
--
--@args config The config file to use (eg, default). Config files require a .lua extension, and are located in <code>nselib/data/psexec</code>.
--@args nohide Don't set the uploaded files to hidden/system/etc.
--@args cleanup Set to only clean up any mess we made (leftover files, processes, etc. on the host OS) on a previous run of the script.
-- This will attempt to delete the files from every share, not just the first one. This is done to prevent leftover
-- files if the OS changes the ordering of the shares (there's no guarantee of shares coming back in any particular
-- order)
-- Note that cleaning up is still fairly invasive, since it has to re-discover the proper share, connect to it,
-- delete files, open the services manager, etc.
--@args share Set to override the share used for uploading. This also stops shares from being enumerated, and all other shares
-- will be ignored. No checks are done to determine whether or not this is a valid share before using it. Reqires
-- <code>sharepath</code> to be set.
--@args sharepath The full path to the share (eg, <code>"c:\windows"</code>). This is required when creating a service.
--@args time The minimum amount of time, in seconds, to wait for the external module to finish (default: <code>15</code>)
--
--@args nocleanup Set to not clean up at all; this leaves the files on the remote system and the wrapper
-- service installed. This is bad in practice, but significantly reduces the network traffic and makes analysis
-- easier.
--@args nocipher Set to disable the ciphering of the returned text (useful for debugging).
--@args key Script uses this value instead of a random encryption key (useful for debugging the crypto).
-----------------------------------------------------------------------
author = "Ron Bowes"
copyright = "Ron Bowes"
license = "Same as Nmap--See https://nmap.org/book/man-legal.html"
categories = {"intrusive"}
dependencies = {"smb-brute"}
-- Where we tell the user to get nmap_service.exe if it's not installed.
local NMAP_SERVICE_EXE_DOWNLOAD = "https://nmap.org/psexec/nmap_service.exe"
hostrule = function(host)
return smb.get_port(host) ~= nil
end
---Get the random-ish filenames used by the service.
--
--@param host The host table, which the names are based on.
--@return Status: true or false.
--@return Name of the remote service, or an error message if status is false.
--@return Name of the executable file that's run by the service.
--@return Name of the temporary output file.
--@return Name of the final output file.
local function get_service_files(host)
local status, service_name, service_file, temp_output_file, output_file
-- Get the name of the service
status, service_name = smb.get_uniqueish_name(host)
if(status == false) then
return false, string.format("Error generating service name: %s", service_name)
end
stdnse.debug1("Generated static service name: %s", service_name)
-- Get the name and service's executable file (with a .txt extension for fun)
status, service_file = smb.get_uniqueish_name(host, "txt")
if(status == false) then
return false, string.format("Error generating remote filename: %s", service_file)
end
stdnse.debug1("Generated static service name: %s", service_name)
-- Get the temporary output file
status, temp_output_file = smb.get_uniqueish_name(host, "out.tmp")
if(status == false) then
return false, string.format("Error generating remote filename: %s", temp_output_file)
end
stdnse.debug1("Generated static service filename: %s", temp_output_file)
-- Get the actual output file
status, output_file = smb.get_uniqueish_name(host, "out")
if(status == false) then
return false, string.format("Error generating remote output file: %s", output_file)
end
stdnse.debug1("Generated static output filename: %s", output_file)
-- Return everything
return true, service_name, service_file, temp_output_file, output_file
end
---Stop/delete the service and delete the service file.
--
--@param host The host object.
--@param config The table of configuration values.
function cleanup(host, config)
local status, err
-- Add a delay here. For some reason, calling this function too quickly causes SMB to close the connection,
-- but even a tiny delay makes that issue go away.
stdnse.sleep(.01)
-- If the user doesn't want to clean up, don't
if(stdnse.get_script_args( "nocleanup" )) then
return
end
stdnse.debug1("Entering cleanup() -- errors here can generally be ignored")
-- Try stopping the service
status, err = msrpc.service_stop(host, config.service_name)
if(status == false) then
stdnse.debug1("[cleanup] Couldn't stop service: %s", err)
end
-- Try deleting the service
status, err = msrpc.service_delete(host, config.service_name)
if(status == false) then
stdnse.debug1("[cleanup] Couldn't delete service: %s", err)
end
-- Delete the files
for _, share in ipairs(config.all_shares) do
status, err = smb.file_delete(host, share, config.all_files)
end
stdnse.debug1("Leaving cleanup()")
return true
end
---Find the file on the system (checks both Nmap's directories and the current
-- directory).
--
--@param filename The name of the file.
--@param extension The extension of the file (filename without the extension is tried first).
--@return The full filename, or nil if it couldn't be found.
local function locate_file(filename, extension)
stdnse.debug1("Attempting to find file: %s", filename)
extension = extension or ""
local filename_full = nmap.fetchfile(filename) or nmap.fetchfile(filename .. "." .. extension)
if(filename_full == nil) then
local psexecfile = "nselib/data/psexec/" .. filename
filename_full = nmap.fetchfile(psexecfile) or nmap.fetchfile(psexecfile .. "." .. extension)
end
-- check for absolute path or relative to current directory
if(filename_full == nil) then
local f, err = io.open(filename, "rb")
if f == nil then
stdnse.debug1("Error opening %s: %s", filename, err)
f, err = io.open(filename .. "." .. extension, "rb")
if f == nil then
stdnse.debug1("Error opening %s.%s: %s", filename, extension, err)
return nil -- unnecessary, but explicit
else
f:close()
return filename .. "." .. extension
end
else
f:close()
return filename
end
end
return filename_full
end
---Generate an array of all files that will be uploaded/created, including
-- the temporary file and the output file. This is done so the files can
-- all be deleted during the cleanup phase.
--
--@param config The config table.
--@return The array of files.
local function get_all_files(config)
local files = {config.service_file, config.output_file, config.temp_output_file}
for _, mod in ipairs(config.enabled_modules) do
-- We're going to delete the module itself
table.insert(files, mod.upload_name)
-- We're also going to delete any temp files...
if(mod.tempfiles) then
for _, file in ipairs(mod.tempfiles) do
table.insert(files, file)
end
end
-- ... and any extra files we uploaded ,,,
if(mod.extrafiles) then
for _, file in ipairs(mod.extrafiles) do
table.insert(files, file)
end
end
-- ... not to mention the output file
if(mod.outfile and mod.outfile ~= "") then
table.insert(files, mod.outfile)
end
end
return files
end
---Decide which share to use. Unless the user overrides it with the 'share' and 'sharepath'
-- arguments, a the first writable share is used.
--
--@param host The host object.
--@return status true for success, false for failure
--@return share The share we're going to use, or an error message.
--@return path The path on the remote system that points to the share.
--@return shares A list of all shares on the system (used for cleaning up).
local function find_share(host)
local status, share, path, shares
-- Determine which share to use
if(nmap.registry.args.share ~= nil) then
share = nmap.registry.args.share
shares = {share}
path = nmap.registry.args.sharepath
if(path == nil) then
return false, "Setting the 'share' script-arg requires the 'sharepath' to be set as well."
end
stdnse.debug1("Using share chosen by the user: %s (%s)", share, path)
else
-- Try and find a share to use.
status, share, path, shares = smb.share_find_writable(host)
if(status == false) then
return false, share .. " (May not have an administrator account)"
end
if(path == nil) then
return false, string.format("Couldn't find path to writable share (we probably don't have admin access): '%s'", share)
end
stdnse.debug1("Found usable share %s (%s) (all writable shares: %s)", share, path, table.concat(shares, ", "))
end
return true, share, path, shares
end
---Recursively replace all variables in the 'setting' field with string variables
-- found in the 'config' field and in the script-args passed by the user.
--
--@param config The configuration table (used as a source of variables to replace).
--@param setting The current setting field (generally a string or a table).
--@return setting The setting with all values replaced.
local function replace_variables(config, setting)
if(type(setting) == "string") then
-- Replace module fields with variables in the script-args argument
for k, v in pairs(nmap.registry.args) do
setting = string.gsub(setting, "$"..k, v)
end
-- Replace module fields with variables in the config file
for k, v in pairs(config) do
if((type(v) == "string" or type(v) == "boolean" or type(v) == "number") and k ~= "key") then
setting = string.gsub(setting, "$"..k, v)
end
end
elseif(type(setting) == "table") then
for k, v in pairs(setting) do
setting[k] = replace_variables(config, v)
end
end
return setting
end
---Takes the 'overrides' field from a module and replace any configuration variables.
--
--@param config The config table.
--@param overrides The overrides we're replacing values with.
--@return config The new config table.
local function do_overrides(config, overrides)
if(overrides) then
if(type(overrides) == 'string') then
overrides = {overrides}
end
for i, v in pairs(overrides) do
config[i] = v
end
end
return config
end
---Reads, prepares, parses, sanity checks, and pre-processes the configuration file (either the
-- default, or the file passed as a parameter).
--
--@param host The host table.
--@param config A table to fill with configuration values.
--@return status true or false
--@return config The configuration table or an error message.
local function get_config(host, config)
local status
local filename = nmap.registry.args.config
config.enabled_modules = {}
config.disabled_modules = {}
-- Find the config file
filename = locate_file(filename or 'default', 'lua')
if(filename == nil) then
return false, "Couldn't locate config file: file not found (make sure it has a .lua extension and is in nselib/data/psexec/)"
end
-- Load the config file
local env = setmetatable({modules = {}; overrides = {}; module = function() stdnse.debug1("WARNING: Selected config file contains an unnecessary call to module()") end}, {__index = _G})
stdnse.debug1("Attempting to load config file: %s", filename)
local file = loadfile(filename, "t", env)
if(not(file)) then
return false, "Couldn't load module file:\n" .. filename
end
-- Run the config file
file()
local modules = env.modules
local overrides = env.overrides
-- Generate a cipher key
if(stdnse.get_script_args( "nocipher" )) then
config.key = ""
elseif(nmap.registry.args.key) then
config.key = nmap.registry.args.key
else
local tmp = {}
for i = 1, 127, 1 do
tmp[i] = string.char(math.random(0x20, 0x7F))
end
config.key = table.concat(tmp)
config.key_index = 0
end
-- Initialize the timeout
config.timeout = 0
-- Figure out which share we're using (this is the first place in the script where a lot of traffic is generated --
-- any possible sanity checking should be done before this)
status, config.share, config.path, config.all_shares = find_share(host)
if(not(status)) then
return false, config.share
end
-- Get information about the socket; it's a bit out of place here, but it should go before the mod loop
status, config.lhost, config.lport, config.rhost, config.rport, config.lmac = smb.get_socket_info(host)
if(status == false) then
return false, "Couldn't get socket information: " .. config.lhost
end
-- Get the names of the files we're going to need
status, config.service_name, config.service_file, config.temp_output_file, config.output_file = get_service_files(host)
if(not(status)) then
return false, config.service_name
end
-- Make sure the modules loaded properly
-- NOTE: If you're here because of an error that 'modules' is undefined, it's likely because your configuration file doesn't have a
-- proper modules table, or your configuration file has a module() declaration at the top.
if(not(modules) or #modules == 0) then
return false, string.format("Configuration file (%s) doesn't have a proper 'modules' table.", filename)
end
-- Make sure we got a proper modules array
if(type(modules) ~= "table") then
return false, string.format("The chosen configuration file, %s.lua, \z
doesn't have a proper 'modules' table. If possible, it should be \z
modified to have a public array called 'modules' that contains a \z
list of all modules that will be run.", filename)
end
-- Loop through the modules for some pre-processing
stdnse.debug1("Verifying uploadable executables exist")
for i, mod in ipairs(modules) do
local enabled = true
-- Do some sanity checking
if(mod.program == nil) then
enabled = false
if(mod.name) then
mod.disabled_message = string.format("Configuration error: '%s': module doesn't have a program", mod.name)
else
mod.disabled_message = string.format("Configuration error: Module #%d doesn't have a program", i)
end
end
-- Set some defaults, if the user didn't specify
mod.name = mod.name or (string.format("%s %s", mod.program, mod.args or ""))
mod.maxtime = mod.maxtime or 1
-- Check if they forgot the uploadibility
if(mod.upload == nil) then
enabled = false
mod.disabled_message = string.format("Configuration error: '%s': 'upload' field is required", mod.name)
end
-- Check if the upload field is set wrong
if(mod.upload ~= true and mod.upload ~= false) then
enabled = false
mod.disabled_message = string.format("Configuration error: '%s': 'upload' field has to be true or false", mod.name)
end
-- Check for incompatible fields with 'headless'
if(mod.headless) then
if(mod.find or mod.remove or mod.noblank or mod.replace or (mod.maxtime > 1) or mod.outfile) then
enabled = false
mod.disabled_message = string.format("Configuration error: '%s': 'headless' is incompatible with find, remove, noblank, replace, and maxtime", mod.name)
end
end
-- Check for improperly formatted 'replace'
if(mod.replace) then
if(type(mod.replace) ~= "table") then
enabled = false
mod.disabled_message = string.format("Configuration error: '%s': 'replace' has to be a table of one-element tables (eg. replace = {{'a'='b'}, {'c'='d'}})", mod.name)
end
for _, v in ipairs(mod.replace) do
if(type(v) ~= 'table') then
enabled = false
mod.disabled_message = string.format("Configuration error: '%s': 'replace' has to be a table of one-element tables (eg. replace = {{'a'='b'}, {'c'='d'}})", mod.name)
end
end
end
-- Set some default values
if(mod.headless == nil) then
mod.headless = false
end
if(mod.include_stderr == nil) then
mod.include_stderr = true
end
-- Make sure required arguments are given
if(mod.req_args) then
if(type(mod.req_args) == 'string') then
mod.req_args = {mod.req_args}
end
-- Keep a table of missing args so we can tell the user all the args they're missing at once
local missing_args = {}
for _, arg in ipairs(mod.req_args) do
if(nmap.registry.args[arg] == nil) then
table.insert(missing_args, arg)
end
end
if(#missing_args > 0) then
enabled = false
mod.disabled_message = {}
table.insert(mod.disabled_message, string.format("Configuration error: Required argument(s) ('%s') weren't given.", table.concat('", missing_args, "')))
table.insert(mod.disabled_message, "Please add --script-args=[arg]=[value] to your commandline to run this module")
if(#missing_args == 1) then
table.insert(mod.disabled_message, string.format("For example: --script-args=%s=123", missing_args[1]))
else
table.insert(mod.disabled_message, string.format("For example: --script-args=%s=123,%s=456...", missing_args[1], missing_args[2]))
end
end
end
-- Checks for the uploadable modules
if(mod.upload) then
-- Check if the module actually exists
stdnse.debug1("Looking for uploadable module: %s or %s.exe", mod.program, mod.program)
mod.filename = locate_file(mod.program, "exe")
if(mod.filename == nil) then
enabled = false
stdnse.debug1("Couldn't find uploadable module %s, disabling", mod.program)
mod.disabled_message = {string.format("Couldn't find uploadable module %s, disabling", mod.program)}
if(mod.url) then
stdnse.debug1("You can try getting it from: %s", mod.url)
table.insert(mod.disabled_message, string.format("You can try getting it from: %s", mod.url))
table.insert(mod.disabled_message, "And placing it in Nmap's nselib/data/psexec/ directory")
end
else
-- We found it
stdnse.debug1("Found: %s", mod.filename)
-- Generate a name to upload them as (we don't upload with the original names)
status, mod.upload_name = smb.get_uniqueish_name(host, "txt", mod.filename)
if(not(status)) then
return false, "Couldn't generate name for uploaded file: " .. mod.upload_name
end
stdnse.debug1("Will upload %s as %s", mod.filename, mod.upload_name)
end
end
-- Prepare extra files
if(enabled and mod.extrafiles) then
-- Make sure we have an array to help save on duplicate code
if(type(mod.extrafiles) == "string") then
mod.extrafiles = {mod.extrafiles}
end
-- Loop through all of the extra files
mod.extrafiles_paths = {}
for i, extrafile in ipairs(mod.extrafiles) do
stdnse.debug1("Looking for extra module: %s", extrafile)
mod.extrafiles_paths[i] = locate_file(extrafile)
if(mod.extrafiles_paths[i] == nil) then
return false, string.format("Couldn't find required file to upload: %s", extrafile)
end
stdnse.debug1("Found: %s", mod.extrafiles_paths[i])
end
end
-- Add the timeout to the total
config.timeout = config.timeout + mod.maxtime
-- Add the module to the appropriate list
if(enabled) then
table.insert(config.enabled_modules, mod)
else
table.insert(config.disabled_modules, mod)
end
end
-- Make a list of *all* files (used for cleaning up)
config.all_files = get_all_files(config)
-- Finalize the timeout
local max_timeout = nmap.registry.args.timeout or 15
config.timeout = math.max(config.timeout, max_timeout)
stdnse.debug1("Timeout waiting for a response is %d seconds", config.timeout)
-- Do config overrides
if(overrides) then
config = do_overrides(config, overrides)
end
-- Replace variable values in the configuration (this has to go last)
stdnse.debug1("Replacing variables in the modules' fields")
for i, mod in ipairs(config.enabled_modules) do
for k, v in pairs(mod) do
mod[k] = replace_variables(config, v)
end
end
return true, config
end
---Cipher (or uncipher) a string with a weak xor-based encryption.
--
--@args str The string go cipher/uncipher.
--@args config The config file for this host (stores the encryption key).
--@return The decrypted string.
local function cipher(str, config)
local result = {}
if(config.key == "") then
return str
end
for i = 1, #str, 1 do
local c = string.byte(str, i)
c = string.char(c ~ string.byte(config.key, config.key_index + 1))
config.key_index = config.key_index + 1
config.key_index = config.key_index % #config.key
result[i] = c
end
return table.concat(result)
end
local function get_overrides()
-- Create some overrides:
-- 0x00004000 = Encrypted
-- 0x00002000 = Don't index this file
-- 0x00000100 = Temporary file
-- 0x00000800 = Compressed file
-- 0x00000002 = Hidden file
-- 0x00000004 = System file
local attr = 0x00000004 | 0x00000002 | 0x00000800 | 0x00000100 | 0x00002000 | 0x00004000
-- Let the user override this behaviour
if(stdnse.get_script_args( "nohide" )) then
attr = 0
end
-- Create the overrides
return {file_create_attributes=attr}
end
--- Check if an nmap_service.exe file is the XOR-encoded version from the 5.21
-- release. It works by checking the first few bytes against a known pattern.
-- Returns <code>true</code> or <code>false</code>, or else <code>nil</code> and
-- an error message.
-- @param filename the name of the file to check.
-- @return status
-- @return error message
local function service_file_is_xor_encoded(filename)
local f, bytes, msg
f, msg = io.open(filename)
if not f then
return nil, msg
end
bytes = f:read(2)
f:close()
if not bytes or #bytes < 2 then
return nil, "Can't read from service file"
end
-- This is the XOR-inverse of "MZ".
return bytes == "\xb2\xa5"
end
---Upload all of the uploadable files to the remote system.
--
--@param host The host table.
--@param config The configuration table.
--@return status true or false
--@return err An error message if status is false.
local function upload_everything(host, config)
local is_xor_encoded, msg
local overrides = get_overrides()
-- In Nmap 5.20, it was discovered that nmap_service.exe file was
-- causing false positives in antivirus software. In an effort to avoid
-- this, in version 5.21 the file was obfuscated by XORing all its bytes
-- with 0xFF. That didn't work, so now the file is not included in the
-- distribution. But it means we must check if we are dealing with the
-- original or XOR-encoded version of the file.
is_xor_encoded, msg = service_file_is_xor_encoded(config.local_service_file)
if is_xor_encoded == nil then
return nil, msg
elseif is_xor_encoded then
stdnse.debug2("%s is the XOR-encoded version from the 5.21 release.", config.local_service_file)
end
-- Upload the service file
stdnse.debug1("Uploading: %s => \\\\%s\\%s", config.local_service_file, config.share, config.service_file)
local status, err
status, err = smb.file_upload(host, config.local_service_file, config.share, "\\" .. config.service_file, overrides, is_xor_encoded)
if(status == false) then
cleanup(host, config)
return false, string.format("Couldn't upload the service file: %s\n", err)
end
stdnse.debug1("Service file successfully uploaded!")
-- Upload the modules and all their extras
stdnse.debug1("Attempting to upload the modules")
for _, mod in ipairs(config.enabled_modules) do
-- If it's an uploadable module, upload it
if(mod.upload) then
stdnse.debug1("Uploading: %s => \\\\%s\\%s", mod.filename, config.share, mod.upload_name)
status, err = smb.file_upload(host, mod.filename, config.share, "\\" .. mod.upload_name, overrides)
if(status == false) then
cleanup(host, config)
return false, string.format("Couldn't upload module %s: %s\n", mod.program, err)
end
end
-- If it requires extra files, upload them, too
if(mod.extrafiles) then
-- Convert to a table, if it's a string
if(type(mod.extrafiles) == "string") then
mod.extrafiles = {mod.extrafiles}
end
-- Loop over the files and upload them
for i, extrafile in ipairs(mod.extrafiles) do
local extrafile_local = mod.extrafiles_paths[i]
stdnse.debug1("Uploading extra file: %s => \\\\%s\\%s", extrafile_local, config.share, extrafile)
status, err = smb.file_upload(host, extrafile_local, config.share, extrafile, overrides)
if(status == false) then
cleanup(host, config)
return false, string.format("Couldn't upload extra file %s: %s\n", extrafile_local, err)
end
end
end
end
stdnse.debug1("Modules successfully uploaded!")
return true
end
---Create the service on the remote system.
--@param host The host object.
--@param config The configuration table.
--@return status true or false
--@return err An error message if status is false.
local function create_service(host, config)
local status, err = msrpc.service_create(host, config.service_name, config.path .. "\\" .. config.service_file)
if(status == false) then
stdnse.debug1("Couldn't create the service: %s", err)
cleanup(host, config)
if(string.find(err, "MARKED_FOR_DELETE")) then
return false, "Service is stuck in 'being deleted' phase on remote machine; try setting script-args=randomseed=abc for now"
else
return false, string.format("Couldn't create the service on the remote machine: %s", err)
end
end
return true
end
---Create the list of parameters we're using to start the service. This consists
-- of a few global params, then a group of parameters with options for each process
-- that's going to be started.
--
--@param config The configuration table.
--@return status true or false
--@return params A table of parameters if status is true, or an error message if status is false.
local function get_params(config)
local count = 0
-- Build the table of parameters to pass to the service
local params = {}
table.insert(params, config.path .. "\\" .. config.output_file)
table.insert(params, config.path .. "\\" .. config.temp_output_file)
table.insert(params, tostring(#config.enabled_modules))
table.insert(params, "0")
table.insert(params, config.key)
table.insert(params, config.path)
for _, mod in ipairs(config.enabled_modules) do
if(mod.upload) then
table.insert(params, config.path .. "\\" .. mod.upload_name .. " " .. (mod.args or ""))
else
table.insert(params, mod.program .. " " .. (mod.args or ""))
end
table.insert(params, (mod.env or ""))
table.insert(params, tostring(mod.headless))
table.insert(params, tostring(mod.include_stderr))
table.insert(params, mod.outfile or "")
end
return true, params
end
---Start the service on the remote machine.
--
--@param host The host object.
--@param config The configuration table.
--@param params The parameters to pass to the service, likely from the <code>get_params</code> function.
--@return status true or false
--@return err An error message if status is false.
local function start_service(host, config, params)
local status, err = msrpc.service_start(host, config.service_name, params)
if(status == false) then
stdnse.debug1("Couldn't start the service: %s", err)
return false, string.format("Couldn't start the service on the remote machine: %s", err)
end
return true
end
---Poll for the output file on the remote machine until either the file is created, or the timeout
-- expires.
--
--@param host The host object.
--@param config The configuration table.
--@return status true or false
--@return result The file if status is true, or an error message if status is false.
local function get_output_file(host, config)
stdnse.debug1("Waiting for output file to be created (timeout = %d seconds)", config.timeout)
local status, result
local i = config.timeout
while true do
status, result = smb.file_read(host, config.share, "\\" .. config.output_file, nil, {file_create_disposition=1})
if(not(status) and result ~= "NT_STATUS_OBJECT_NAME_NOT_FOUND") then
-- An unexpected error occurred
stdnse.debug1("Couldn't read the file: %s", result)
cleanup(host, config)
return false, string.format("Couldn't read the file from the remote machine: %s", result)
end
if(not(status) and result == "NT_STATUS_OBJECT_NAME_NOT_FOUND") then
-- An expected error occurred; if this happens, we just wait
if(i == 0) then
stdnse.debug1("Error in remote service: output file was never created!")
cleanup(host, config)
return false, "Error in remote service: output file was never created"
end
stdnse.debug1("Output file %s doesn't exist yet, waiting for %d more seconds", config.output_file, i)
stdnse.sleep(1)
i = i - 1
end
if(status) then
break
end
end
return true, result
end
---Decide whether or not a line should be included in the output file, based on the module's
-- find, remove, and noblank settings.
local function should_be_included(mod, line)
local removed, found
-- Remove lines from the output, if the module requested it
removed = false
if(mod.remove and #mod.remove > 0) then
-- Make a single string into a table to save code
if(type(mod.remove) ~= 'table') then
mod.remove = {mod.remove}
end
-- Loop through the module's find table to see if any of the lines match
for _, remove in ipairs(mod.remove) do
if(string.match(line, remove)) then
removed = true
break
end
end
end
-- Remove blank lines if we're supposed to
if(mod.noblank and line == "") then
removed = true
end
-- If the line wasn't removed, and we are searching for specific text, do the search
found = false
if(mod.find and #mod.find > 0 and not(removed)) then
-- Make a single string a table to save duplicate code
if(type(mod.find) ~= 'table') then
mod.find = {mod.find}
end
-- Loop through the module's find table to see if any of the lines match
for _, find in ipairs(mod.find) do
if(string.match(line, find)) then
found = true
break
end
end
else
found = true
end
-- Only display the line if it's found and not removed
return (found and not(removed))
end
---Alter a line based on the module's 'replace' setting.
local function do_replacements(mod, line)
if(mod.replace) then
for _, v in pairs(mod.replace) do
line = string.gsub(line, v[1], v[2])
end
end
return line
end
---Parse the output file into a neat array.
local function parse_output(config, data)
-- Allow 'data' to be nil. This lets us skip most of the effort when all mods are disabled
data = data or ""
-- Split the result at newlines
local lines = stringaux.strsplit("\n", data)
local module_num = -1
local mod = nil
local result = nil
-- Loop through the lines and parse them into the results table
local results = {}
for _, line in ipairs(lines) do
if(line ~= "") then
local this_module_num = tonumber(string.sub(line, 1, 1))
-- Get the important part of the line
line = string.sub(line, 2)
-- Remove the Windows endline (0x0a) from the string (these are left in up to this point to maintain
-- the ability to download binary files, if that ever comes up
line = string.gsub(line, "\r", "")
-- If the module_number has changed, increment to the next module
if(this_module_num ~= (module_num % 10)) then
-- Increment our module number
if(module_num < 0) then
module_num = 0
else
module_num = module_num + 1
end
-- Go to the next module, and make sure it exists
mod = config.enabled_modules[module_num + 1]
if(mod == nil) then
stdnse.debug1("Server's response wasn't formatted properly (mod %d); if you can reproduce, place report to dev@nmap.org", module_num)
stdnse.debug1("--\n" .. string.gsub("%%", "%%", data) .. "\n--")
return false, "Server's response wasn't formatted properly; if you can reproduce, place report to dev@nmap.org"
end
-- Save this result
if(result ~= nil) then
table.insert(results, result)
end
result = {}
result['name'] = "<no name>"
result['lines'] = {}
if(mod.name) then
result['name'] = mod.name
else
result['name'] = string.format("'%s %s;", mod.program, (mod.args or ""))
end
end
local include = should_be_included(mod, line)
-- If we're including it, do the replacements
if(include) then
line = do_replacements(mod, line)
table.insert(result, line)
end
end
end
table.insert(results, result)
-- Loop through the disabled modules and print them out
for _, mod in ipairs(config.disabled_modules) do
local result = {}
result['name'] = mod.name
if(mod.disabled_message == nil) then
mod.disabled_message = {"No reason for disabling the module was found"}
end
if(type(mod.disabled_message) == 'string') then
mod.disabled_message = {mod.disabled_message}
end
for _, message in ipairs(mod.disabled_message) do
table.insert(result, "WARNING: " .. message)
end
table.insert(results, result)
end
return true, results
end
action = function(host)
local status, result, err
local key
local i
local params
local config = {}
local files
-- First check for nmap_service.exe; we can't do anything without it.
stdnse.debug1("Looking for the service file: nmap_service or nmap_service.exe")
config.local_service_file = locate_file("nmap_service", "exe")
if (config.local_service_file == nil) then
if nmap.verbosity() > 0 then
return string.format([[
Can't find the service file: nmap_service.exe (or nmap_service).
Due to false positives in antivirus software, this module is no
longer included by default. Please download it from
%s
and place it in nselib/data/psexec/ under the Nmap DATADIR.
]], NMAP_SERVICE_EXE_DOWNLOAD)
else
return
end
end
-- Parse the configuration file
status, config = get_config(host, config)
if(not(status)) then
return stdnse.format_output(false, config)
end
if(#config.enabled_modules > 0) then
-- Start by cleaning up, just in case.
cleanup(host, config)
-- If the user just wanted a cleanup, do it
if(stdnse.get_script_args( "cleanup" )) then
return stdnse.format_output(true, "Cleanup complete.")
end
-- Check if any of the files exist
status, result, files = smb.files_exist(host, config.share, config.all_files, {})
if(not(status)) then
return stdnse.format_output(false, "Couldn't log in to check for remote files: " .. result)
end
if(result > 0) then
local response = {}
table.insert(response, "One or more output files already exist on the host, and couldn't be removed. Try:")
table.insert(response, "* Running the script with --script-args=cleanup=1 to force a cleanup (passing -d and looking for error messages might help),")
table.insert(response, "* Running the script with --script-args=randomseed=ABCD (or something) to change the name of the uploaded files,")
table.insert(response, "* Changing the share and path using, for example, --script-args=share=C$,sharepath=C:, or")
table.insert(response, "* Deleting the affected file(s) off the server manually (\\\\" .. config.share .. "\\" .. table.concat(files, ", \\\\" .. config.share .. "\\") .. ")")
return stdnse.format_output(false, response)
end
-- Upload the modules
status, err = upload_everything(host, config)
if(not(status)) then
cleanup(host, config)
return stdnse.format_output(false, err)
end
-- Create the service
status, err = create_service(host, config)
if(not(status)) then
cleanup(host, config)
return stdnse.format_output(false, err)
end
-- Get the table of parameters to pass to the service when we start it
status, params = get_params(config)
if(not(status)) then
cleanup(host, config)
return stdnse.format_output(false, params)
end
-- Start the service
status, params = start_service(host, config, params)
if(not(status)) then
cleanup(host, config)
return stdnse.format_output(false, params)
end
-- Get the result
status, result = get_output_file(host, config, config.share)
if(not(status)) then
cleanup(host, config)
return stdnse.format_output(false, result)
end
-- Do a final cleanup
cleanup(host, config)
-- Uncipher the file
result = cipher(result, config)
end
-- Build the output into a nice table
local response
status, response = parse_output(config, result)
if(status == false) then
return stdnse.format_output(false, "Couldn't parse output: " .. response)
end
-- Add a warning if nothing was enabled
if(#config.enabled_modules == 0) then
if(#response == 0) then
response = {"No modules were enabled! Please check your configuration file."}
else
table.insert(response, "No modules were enabled! Please fix any errors displayed above, or check your configuration file.")
end
end
-- Return the string
return stdnse.format_output(true, response)
end