DevilsTongue_HijackDll

YARA detection rule by Microsoft Threat Intelligence Center (MSTIC) · GPL-2.0

Detects SOURGUM's DevilsTongue hijack DLL

import "pe"
rule DevilsTongue_HijackDll {
  meta:
    description = "Detects SOURGUM's DevilsTongue hijack DLL"
    reference   = "https://www.microsoft.com/security/blog/2021/07/15/protecting-customers-from-a-private-sector-offensive-actor-using-0-day-exploits-and-devilstongue-malware/"
    author      = "Microsoft Threat Intelligence Center (MSTIC)"
    date        = "2021-07-15"

  strings:
    $str1  = "windows.old\\windows" wide
    $str2  = "NtQueryInformationThread"
    $str3  = "dbgHelp.dll" wide
    $str4  = "StackWalk64"
    $str5  = "ConvertSidToStringSidW"
    $str6  = "S-1-5-18" wide
    $str7  = "SMNew.dll"                          $code1 = { B8 FF 15 00 00 66 39 41 FA 74 06 80 79 FB E8 }
                                                    $code2 = { 44 8B C0 B8 B5 81 4E 1B 41 F7 E8 C1 FA 05 8B CA C1 E9 1F 03 D1 69 CA 2C 01 00 00 44 2B C1 45 85 C0 7E 19 }

  condition:
    filesize < 800KB and
    uint16(0) == 0x5A4D and
    (pe.characteristics & pe.DLL) and
    (
      4 of them or
      ($code1 and $code2) or
      (pe.imphash() == "9a964e810949704ff7b4a393d9adda60")
    )
}

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

930f01d8-246b-4b1c-b8f4-b06e225abdf0

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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 ]]

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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 ]]

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

[[ currentRule.title ]]

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