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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_APT_Sandworm_Keywords_May20_1

Detects commands used by Sandworm group to exploit critical vulernability CVE-2019-10149 in Exim

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 commands used by Sandworm group to exploit critical vulernability CVE-2019-10149 in Exim

It defines 2 patterns (2 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
apt-sandworm-keywords-may20-1.yarDetection Rule License 1.1
rule SIGNATURE_BASE_APT_Sandworm_Keywords_May20_1 : CVE_2019_10149 FILE
{
	meta:
		description = "Detects commands used by Sandworm group to exploit critical vulernability CVE-2019-10149 in Exim"
		author = "Florian Roth (Nextron Systems)"
		id = "e0d4e90e-5547-5487-8d0c-a141d88fff7c"
		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#L2-L15"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		logic_hash = "9f9a81ff0c576f05ac063eaca7a5882dbdb09c9a0778610cca2864636a00efce"
		score = 75
		quality = 85
		tags = "CVE-2019-10149, FILE"

	strings:
		$x1 = "MAIL FROM:<$(run("
		$x2 = "exec\\x20\\x2Fusr\\x2Fbin\\x2Fwget\\x20\\x2DO\\x20\\x2D\\x20http"

	condition:
		filesize < 8000KB and 1 of them
}

Strings (2 patterns)

IdentifierTypeValueModifiers
$x1text"MAIL FROM:<$(run("
$x2text"exec\\x20\\x2Fusr\\x2Fbin\\x2Fwget\\x20\\x2DO\\x20\\x2D\\x20http"

Condition

filesize < 8000KB and 1 of them

In plain words (Heuristic)

  • The file must be smaller than 8000KB (a cheap guard that skips large files).
  • At least 1 patterns in the rule must match.

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References

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: e0d4e90e-5547-5487-8d0c-a141d88fff7c

Tags:CVE_2019_10149FILE

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