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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_MAL_Grace_Dec22

Detects Grace (aka FlawedGrace and GraceWire) RAT

MalwareFlawedgraceSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
X__Junior
Date
2022-12-13
Modified
2023-12-05
Score / Quality
70 / 85

What this rule detects

Detects Grace (aka FlawedGrace and GraceWire) RAT

Associated malware family: Flawedgrace.

It defines 6 patterns (6 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
mal-grace-dec22.yarDetection Rule License 1.1
rule SIGNATURE_BASE_MAL_Grace_Dec22
{
	meta:
		description = "Detects Grace (aka FlawedGrace and GraceWire) RAT"
		author = "X__Junior"
		id = "fc2214dc-f1e5-52d7-a9de-88709a03b04e"
		date = "2022-12-13"
		modified = "2023-12-05"
		reference = "https://blog.talosintelligence.com/breaking-the-silence-recent-truebot-activity/"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/expl_sysaid_cve_2023_47246.yar#L40-L59"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "a66df3454b8c13f1b92d8b2cf74f5bfcdedfbff41a5e4add62e15277d14dd169"
		hash = "e113a8df3c4845365f924bacf10c00bcc5e17587a204b640852dafca6db20404"
		logic_hash = "8276662dadfa2f8e07dd7882a60e55bd22ecf1f8f66a09940f16236598646560"
		score = 70
		quality = 85
		tags = ""

	strings:
		$sa1 = "Grace finalized, no more library calls allowed." ascii
		$sa2 = "Socket forcibly closed due to no response to DISCONNECT signal from other side, worker id(%d)" ascii
		$sa3 = "AVWireCleanupThread" ascii
		$sa4 = "AVTunnelClientDirectIO" ascii
		$sa5 = "AVGraceTunnelWriteThread" ascii
		$sa6 = "AVGraceTunnelClientDirectIO" ascii

	condition:
		2 of them
}

Strings (6 patterns)

IdentifierTypeValueModifiers
$sa1text"Grace finalized, no more library calls allowed."ascii
$sa2text"Socket forcibly closed due to no response to DISCONNECT signal from other side, worker id(%d)"ascii
$sa3text"AVWireCleanupThread"ascii
$sa4text"AVTunnelClientDirectIO"ascii
$sa5text"AVGraceTunnelWriteThread"ascii
$sa6text"AVGraceTunnelClientDirectIO"ascii

Condition

2 of them

In plain words (Heuristic)

  • At least 2 patterns in the rule must match.

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References

Sample hashes

Hashes of samples the author lists in the rule's meta (look them up in your threat-intelligence platform).

  • a66df3454b8c13f1b92d8b2cf74f5bfcdedfbff41a5e4add62e15277d14dd169
  • e113a8df3c4845365f924bacf10c00bcc5e17587a204b640852dafca6db20404

Licence & attribution

Author: X__Junior

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: fc2214dc-f1e5-52d7-a9de-88709a03b04e

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