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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_SUSP_MAL_Signingcert_Feb24_1

Detects PE files signed with a certificate used to sign malware samples mentioned in a HuntressLabs report on the exploitation of ScreenConnect vulnerability CVE-2024-1708 and CVE-2024-1709

Suspicious / huntingSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
Florian Roth
Date
2024-02-23
Modified
2024-04-24
Score / Quality
75 / 85

What this rule detects

Detects PE files signed with a certificate used to sign malware samples mentioned in a HuntressLabs report on the exploitation of ScreenConnect vulnerability CVE-2024-1708 and CVE-2024-1709

Targets: Windows PE.

It defines 3 patterns (2 text, 1 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

susp-mal-signingcert-feb24-1.yarDetection Rule License 1.1
rule SIGNATURE_BASE_SUSP_MAL_Signingcert_Feb24_1 : CVE_2024_1708 CVE_2024_1709 FILE
{
	meta:
		description = "Detects PE files signed with a certificate used to sign malware samples mentioned in a HuntressLabs report on the exploitation of ScreenConnect vulnerability CVE-2024-1708 and CVE-2024-1709"
		author = "Florian Roth"
		id = "f25ea77a-1b4e-5c13-9117-eedf0c20335a"
		date = "2024-02-23"
		modified = "2024-04-24"
		reference = "https://www.huntress.com/blog/slashandgrab-screen-connect-post-exploitation-in-the-wild-cve-2024-1709-cve-2024-1708"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/expl_connectwise_screenconnect_vuln_feb24.yar#L166-L184"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "37a39fc1feb4b14354c4d4b279ba77ba51e0d413f88e6ab991aad5dd6a9c231b"
		hash = "e8c48250cf7293c95d9af1fb830bb8a5aaf9cfb192d8697d2da729867935c793"
		logic_hash = "824efe1fa441322d891805df9a1637ebb44d18889572604acc125bf79a2d1083"
		score = 75
		quality = 85
		tags = "CVE-2024-1708, CVE-2024-1709, FILE"

	strings:
		$s1 = "Wisdom Promise Security Technology Co." ascii
		$s2 = "Globalsign TSA for CodeSign1" ascii
		$s3 = { 5D AC 0B 6C 02 5A 4B 21 89 4B A3 C2 }

	condition:
		uint16( 0 ) == 0x5a4d and filesize < 70000KB and all of them
}

Strings (3 patterns)

IdentifierTypeValueModifiers
$s1text"Wisdom Promise Security Technology Co."ascii
$s2text"Globalsign TSA for CodeSign1"ascii
$s3hex{ 5D AC 0B 6C 02 5A 4B 21 89 4B A3 C2 }

Condition

uint16( 0 ) == 0x5a4d and filesize < 70000KB and all of them

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • The file must be smaller than 70000KB (a cheap guard that skips large files).
  • All 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).

  • 37a39fc1feb4b14354c4d4b279ba77ba51e0d413f88e6ab991aad5dd6a9c231b
  • e8c48250cf7293c95d9af1fb830bb8a5aaf9cfb192d8697d2da729867935c793

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: f25ea77a-1b4e-5c13-9117-eedf0c20335a

Tags:CVE_2024_1708CVE_2024_1709FILE