YARA · Signature Base (Florian Roth / Nextron)
SIGNATURE_BASE_MAL_CS_Loader_Feb24_1
Detects Cobalt Strike malware samples mentioned in a HuntressLabs report on the exploitation of ScreenConnect vulnerability CVE-2024-1708 and CVE-2024-1709
- Author
- Florian Roth
- Date
- 2024-02-23
- Modified
- 2024-04-24
- Score / Quality
- 75 / 85
What this rule detects
Detects Cobalt Strike 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 1 patterns (1 text, 0 hex, 0 regex). YARA modules used: pe.
Summary generated from the rule's metadata and condition.
Rule source
Includes the imports needed to compile it on its own.
import "pe"
rule SIGNATURE_BASE_MAL_CS_Loader_Feb24_1 : CVE_2024_1708 CVE_2024_1709 FILE
{
meta:
= "Detects Cobalt Strike malware samples mentioned in a HuntressLabs report on the exploitation of ScreenConnect vulnerability CVE-2024-1708 and CVE-2024-1709"
= "Florian Roth"
= "6c9914a4-b079-5a39-9d3b-7b9a2b54dc2b"
= "2024-02-23"
= "2024-04-24"
= "https://www.huntress.com/blog/slashandgrab-screen-connect-post-exploitation-in-the-wild-cve-2024-1709-cve-2024-1708"
= "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/expl_connectwise_screenconnect_vuln_feb24.yar#L186-L206"
= "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
= "0a492d89ea2c05b1724a58dd05b7c4751e1ffdd2eab3a2f6a7ebe65bf3fdd6fe"
= "ae0e25c2dda1b727978977c674e834cd659661c597d88395a6f46ad5a179e9f0"
= 75
= 85
= "CVE-2024-1708, CVE-2024-1709, FILE"
strings:
$s1 = "Dll_x86.dll" ascii fullword
condition:
uint16( 0 ) == 0x5a4d and filesize < 1000KB and ( pe.exports ( "UpdateSystem" ) and ( pe.imphash ( ) == "0dc05c4c21a86d29f1c3bf9cc5b712e0" or $s1 ) )
}
Strings (1 patterns)
| Identifier | Type | Value | Modifiers |
|---|---|---|---|
| $s1 | text | "Dll_x86.dll" | ascii fullword |
Condition
uint16( 0 ) == 0x5a4d and filesize < 1000KB and ( pe.exports ( "UpdateSystem" ) and ( pe.imphash ( ) == "0dc05c4c21a86d29f1c3bf9cc5b712e0" or $s1 ) )In plain words (Heuristic)
- The file must start with “MZ” — a Windows executable (PE).
- The file must be smaller than 1000KB (a cheap guard that skips large files).
- Uses the pe module.
- Pattern $s1 must be present.
- Checks the PE import hash (imphash).
- Checks exported functions or the DLL name.
Test this rule in your browser
Drop a file to scan it with this rule using YARA-X compiled to WebAssembly. Nothing is uploaded.
Sample hashes
Hashes of samples the author lists in the rule's meta (look them up in your threat-intelligence platform).
- 0a492d89ea2c05b1724a58dd05b7c4751e1ffdd2eab3a2f6a7ebe65bf3fdd6fe
Licence & attribution
Author: Florian Roth
Source repository: Signature Base (Florian Roth / Nextron) @ 94a1c48d7a
Licence: Detection Rule License 1.1 (repository licence)
Mirrored via YARA Forge 20260927, which prefixes rule names with the source and adds normalised meta fields.
Rule id: 6c9914a4-b079-5a39-9d3b-7b9a2b54dc2b
Tags:CVE_2024_1708CVE_2024_1709FILE
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