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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_MAL_APT_NK_Andariel_Tigerrat_Crowdsourced_Rule

Detects the Tiger RAT variant used by Andariel

MalwareTiger RatSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
CISA.gov (modified by Florian Roth, Nextron Systems)
Date
2024-07-25
Modified
2024-07-26
Score / Quality
75 / 85

What this rule detects

Detects the Tiger RAT variant used by Andariel

Associated malware family: Tiger Rat.

Targets: Windows PE.

It defines 8 patterns (8 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
mal-apt-nk-andariel-tigerrat-crowdsourced-rule.yarDetection Rule License 1.1
rule SIGNATURE_BASE_MAL_APT_NK_Andariel_Tigerrat_Crowdsourced_Rule : FILE
{
	meta:
		description = "Detects the Tiger RAT variant used by Andariel"
		author = "CISA.gov (modified by Florian Roth, Nextron Systems)"
		id = "6be65222-7d3c-5ff5-a9c7-d91dcf1deaa6"
		date = "2024-07-25"
		modified = "2024-07-26"
		reference = "https://www.cisa.gov/news-events/cybersecurity-advisories/aa24-207a"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/apt_nk_andariel_jul24.yar#L395-L424"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		logic_hash = "5d203d8c7e624796571f4597f70be0b8303f21c096640f25018cad29d4abc05b"
		score = 75
		quality = 85
		tags = "FILE"

	strings:
		$m1 = ".?AVModuleKeyLogger@@" fullword ascii
		$m2 = ".?AVModulePortForwarder@@" fullword ascii
		$m3 = ".?AVModuleScreenCapture@@" fullword ascii
		$m4 = ".?AVModuleShell@@" fullword ascii
		$s1 = "\\x9891-009942-xnopcopie.dat" fullword wide
		$s2 = "(%02d : %02d-%02d %02d:%02d:%02d)--- %s[Clipboard]" fullword ascii
		$s3 = "[%02d : %02d-%02d %02d:%02d:%02d]--- %s[Title]" fullword ascii
		$s4 = "del \"%s\"%s \"%s\" goto " ascii

	condition:
		uint16( 0 ) == 0x5a4d and ( all of ( $s* ) or ( all of ( $m* ) and 1 of ( $s* ) ) or ( 2 of ( $m* ) and 2 of ( $s* ) ) )
}

Strings (8 patterns)

IdentifierTypeValueModifiers
$m1text".?AVModuleKeyLogger@@"fullword ascii
$m2text".?AVModulePortForwarder@@"fullword ascii
$m3text".?AVModuleScreenCapture@@"fullword ascii
$m4text".?AVModuleShell@@"fullword ascii
$s1text"\\x9891-009942-xnopcopie.dat"fullword wide
$s2text"(%02d : %02d-%02d %02d:%02d:%02d)--- %s[Clipboard]"fullword ascii
$s3text"[%02d : %02d-%02d %02d:%02d:%02d]--- %s[Title]"fullword ascii
$s4text"del \"%s\"%s \"%s\" goto "ascii

Condition

uint16( 0 ) == 0x5a4d and ( all of ( $s* ) or ( all of ( $m* ) and 1 of ( $s* ) ) or ( 2 of ( $m* ) and 2 of ( $s* ) ) )

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • All patterns in ( $s* ) must match.
  • All patterns in ( $m* ) must match.
  • At least 1 patterns in ( $s* ) must match.
  • At least 2 patterns in ( $m* ) must match.
  • At least 2 patterns in ( $s* ) must match.

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References

Licence & attribution

Author: CISA.gov (modified by Florian Roth, Nextron Systems)

Source repository: Signature Base (Florian Roth / Nextron) @ 94a1c48d7a

Licence: Detection Rule License 1.1 (repository licence)

Original rule

Mirrored via YARA Forge 20260927, which prefixes rule names with the source and adds normalised meta fields.

Rule id: 6be65222-7d3c-5ff5-a9c7-d91dcf1deaa6

Tags:FILE

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