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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_EXPL_Cleo_Exploitation_XML_Indicators_Dec24

Detects XML used during and after Cleo software exploitation (as reported by Huntress in December 2024)

ExploitSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
Florian Roth
Date
2024-12-10
Modified
2024-12-12
Score / Quality
70 / 85

What this rule detects

Detects XML used during and after Cleo software exploitation (as reported by Huntress in December 2024)

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

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
expl-cleo-exploitation-xml-indicators-dec24.yarDetection Rule License 1.1
rule SIGNATURE_BASE_EXPL_Cleo_Exploitation_XML_Indicators_Dec24 : FILE
{
	meta:
		description = "Detects XML used during and after Cleo software exploitation (as reported by Huntress in December 2024)"
		author = "Florian Roth"
		id = "622633af-aa7a-5bf9-a59c-6590535d86a4"
		date = "2024-12-10"
		modified = "2024-12-12"
		reference = "https://www.huntress.com/blog/threat-advisory-oh-no-cleo-cleo-software-actively-being-exploited-in-the-wild"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/expl_cleo_dec24.yar#L91-L109"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		logic_hash = "21c11c3e0c0ffea89e24b9c002b6112a46b4dc7c2c4f1f5dc9803758a68efc36"
		score = 70
		quality = 85
		tags = "FILE"

	strings:
		$x1 = "<Host alias=\"60282967-dc91-40ef-a34c-38e992509c2c\" application=\"\" " ascii
		$s1 = "<Commands>SYSTEM cmd.exe /c " ascii
		$a1 = "<Action actiontype=\"Commands\" " ascii

	condition:
		filesize < 50KB and ( 1 of ( $x* ) or 2 of them )
}

Strings (3 patterns)

IdentifierTypeValueModifiers
$x1text"<Host alias=\"60282967-dc91-40ef-a34c-38e992509c2c\" application=\"\" "ascii
$s1text"<Commands>SYSTEM cmd.exe /c "ascii
$a1text"<Action actiontype=\"Commands\" "ascii

Condition

filesize < 50KB and ( 1 of ( $x* ) or 2 of them )

In plain words (Heuristic)

  • The file must be smaller than 50KB (a cheap guard that skips large files).
  • At least 1 patterns in ( $x* ) must match.
  • At least 2 patterns in the rule must match.

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References

Licence & attribution

Author: Florian Roth

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: 622633af-aa7a-5bf9-a59c-6590535d86a4

Tags:FILE

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