Pikabot 20230525 Execs

KQL detection rule by reversinglabs · MIT

PikaBot process execution seen for week of 2023-05-25

// description: PikaBot process execution seen for week of 2023-05-25
let EncodedKeywords = dynamic(['-encodedcommand', '-enc']);
let DecodedCommands = dynamic([
  "start rundll32 $env:ProgramData\\neighbourer.OutmarchesBisinuate,vips;slack.com", 
  "start rundll32 $env:ProgramData\\trichoglossidae.Symphily,vips;MITLicense", 
  "start rundll32 $env:TEMP\\amphibolostylous.grommets,Test;Expressjs", 
  "start rundll32 C:\\ProgramData\\reknowMechant.montageFirring,DllRegisterServer;Angular"]);
SecurityEvent
  | where EventID == 4688
  | where Process == "wscript.exe" and CommandLine matches regex @"C:\\Users\\.*\\AppData\\Local\\Temp\\.*\.js"
| union (SecurityEvent
  | where EventID == 4688
    | where Process contains "powershell"
    | where CommandLine has_any (EncodedKeywords)
    | extend EncodedCommand = extract(@'\s+([A-Za-z0-9+/]{20}\S+$)', 1, CommandLine)
    | extend DecodedCommand = base64_decode_tostring(EncodedCommand)
    | where not(isempty(EncodedCommand) and isempty(DecodedCommand))
    | where DecodedCommand has_any (DecodedCommands)
), 
(DeviceProcessEvents
  | where FileName == "wscript.exe" and ProcessCommandLine matches regex @"C:\\Users\\.*\\AppData\\Local\\Temp\\.*\.js"
),
(DeviceProcessEvents
  | where ProcessCommandLine contains "powershell" or InitiatingProcessCommandLine contains "powershell"
  | where ProcessCommandLine has_any (EncodedKeywords) or InitiatingProcessCommandLine has_any (EncodedKeywords)
  | extend EncodedCommand = extract(@'\s+([A-Za-z0-9+/]{20}\S+$)', 1, ProcessCommandLine)
  | extend DecodedCommand = base64_decode_tostring(EncodedCommand)
  | where not(isempty(EncodedCommand) and isempty(DecodedCommand))
  | where DecodedCommand has_any (DecodedCommands)
)

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

a54ef5dd-09c6-4862-9ba0-9e865bfce6a0

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Executable code, not a declarative rule

This submission is arbitrary [[ currentRule.format ? currentRule.format.toUpperCase() : '' ]] code, not a declarative detection rule — review it as you would any script before running it, and note that it cannot be safely aggregated or auto-executed alongside YARA/Sigma/Suricata/CRS rules.

Rejected pattern present

[[ reason ]]

What does this mean?

Format & documentation suggestions

Not a security issue — this rule is valid and was accepted as-is. These are optional fields/conventions its own format recommends, mainly affecting its quality score and how well it documents itself for other reviewers.

[[ reason ]]

What do these messages mean?

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

[[ currentRule.title ]]

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