IIS_Group02

YARA detection rule by ESET Research · BSD 2-Clause

Detects Group 2 native IIS malware family

rule IIS_Group02 {

    meta:
        description = "Detects Group 2 native IIS malware family"
        author = "ESET Research"
        date = "2021-08-04"
        reference = "https://www.welivesecurity.com/"
        source = "https://github.com/eset/malware-ioc/"
        license = "BSD 2-Clause"
        version = "1"

    strings:
        $s1 = "HttpModule.pdb" ascii wide
        $s2 = "([\\w+%]+)=([^&]*)"
        $s3 = "([\\w+%]+)=([^!]*)"
        $s4 = "cmd.exe"
        $s5 = "C:\\Users\\Iso\\Documents\\Visual Studio 2013\\Projects\\IIS 5\\x64\\Release\\Vi.pdb" ascii wide
        $s6 = "AVRSAFunction"

    condition:
        IIS_Native_Module and 3 of ($s*)
}

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

e08b6ac5-6758-4a5d-ac08-cc97767da00f

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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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