YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_APT_Sandworm_User_May20_1

Detects user added by Sandworm on compromised machines

APT / threat actorSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X

Author: Florian Roth (Nextron Systems)
Date: 2020-05-28
Modified: 2023-12-05
Score / Quality: 75 / 85

What this rule detects

Detects user added by Sandworm on compromised machines

It defines 3 patterns (3 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar

apt-sandworm-user-may20-1.yarDetection Rule License 1.1

rule SIGNATURE_BASE_APT_Sandworm_User_May20_1 : FILE
{
	meta:
		description = "Detects user added by Sandworm on compromised machines"
		author = "Florian Roth (Nextron Systems)"
		id = "ada549a4-abcc-5c0a-9601-75631e78c835"
		date = "2020-05-28"
		modified = "2023-12-05"
		reference = "https://media.defense.gov/2020/May/28/2002306626/-1/-1/0/CSA%20Sandworm%20Actors%20Exploiting%20Vulnerability%20in%20Exim%20Transfer%20Agent%2020200528.pdf"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/apt_sandworm_exim_expl.yar#L68-L84"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "dc074464e50502459038ac127b50b8c68ed52817a61c2f97f0add33447c8f730"
		hash = "538d713cb47a6b5ec6a3416404e0fc1ebcbc219a127315529f519f936420c80e"
		logic_hash = "d052792a674dfa2d93a048b550ea085c3b9225662fdb09bf4a602093b0527e38"
		score = 75
		quality = 85
		tags = "FILE"

	strings:
		$s1 = "mysql_db:x:" ascii
		$a1 = "root:x:"
		$a2 = "daemon:x:"

	condition:
		filesize < 4KB and all of them
}

Strings (3 patterns)

Identifier	Type	Value	Modifiers
$s1	text	"mysql_db:x:"	ascii
$a1	text	"root:x:"
$a2	text	"daemon:x:"

Condition

filesize < 4KB and all of them

In plain words (Heuristic)

The file must be smaller than 4KB (a cheap guard that skips large files).
All patterns in the rule must match.

Test this rule in your browser

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Drop a file here or click to chooseScanned locally with YARA-X. Files up to 200 MB.

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References

https://media.defense.gov/2020/May/28/2002306626/-1/-1/0/CSA%20Sandworm%20Actors%20Exploiting%20Vulnerability%20in%20Exim%20Transfer%20Agent%2020200528.pdf

Sample hashes

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

dc074464e50502459038ac127b50b8c68ed52817a61c2f97f0add33447c8f730
538d713cb47a6b5ec6a3416404e0fc1ebcbc219a127315529f519f936420c80e

Licence & attribution

Author: 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: ada549a4-abcc-5c0a-9601-75631e78c835

Tags:FILE

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