YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_APT_Sandworm_SSH_Key_May20_1

Detects SSH key used by Sandworm on exploited 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 SSH key used by Sandworm on exploited machines

It defines 1 patterns (1 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar

apt-sandworm-ssh-key-may20-1.yarDetection Rule License 1.1

rule SIGNATURE_BASE_APT_Sandworm_SSH_Key_May20_1 : FILE
{
	meta:
		description = "Detects SSH key used by Sandworm on exploited machines"
		author = "Florian Roth (Nextron Systems)"
		id = "ea2968b8-7ae4-56b8-9547-816c5e37c50a"
		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#L17-L31"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "dc074464e50502459038ac127b50b8c68ed52817a61c2f97f0add33447c8f730"
		hash = "538d713cb47a6b5ec6a3416404e0fc1ebcbc219a127315529f519f936420c80e"
		logic_hash = "23a43849dfaa80bad2ca4f46b53181b3a4855ee89673ae9b658c854069b9aaa9"
		score = 75
		quality = 85
		tags = "FILE"

	strings:
		$x1 = "ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQC2q/NGN/brzNfJiIp2zswtL33tr74pIAjMeWtXN1p5Hqp5fTp058U1EN4NmgmjX0KzNjjV"

	condition:
		filesize < 1000KB and 1 of them
}

Strings (1 patterns)

Identifier	Type	Value	Modifiers
$x1	text	"ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQC2q/NGN/brzNfJiIp2zswtL33tr74pIAjMeWtXN1p5Hqp5fTp058U1EN4NmgmjX0KzNjjV"

Condition

filesize < 1000KB and 1 of them

In plain words (Heuristic)

The file must be smaller than 1000KB (a cheap guard that skips large files).
At least 1 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: ea2968b8-7ae4-56b8-9547-816c5e37c50a

Tags:FILE

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