YARA · Signature Base (Florian Roth / Nextron)
SIGNATURE_BASE_EXPL_Cleo_Exploitation_JAVA_Payloads_Dec24_2
Detects characteristics of JAVA files used during Cleo software exploitation (as reported by Huntress in December 2024) - file Proc
- Author
- Florian Roth
- Date
- 2024-12-10
- Modified
- 2024-12-12
- Score / Quality
- 75 / 85
What this rule detects
Detects characteristics of JAVA files used during Cleo software exploitation (as reported by Huntress in December 2024) - file Proc
It defines 4 patterns (4 text, 0 hex, 0 regex).
Summary generated from the rule's metadata and condition.
Rule source
rule SIGNATURE_BASE_EXPL_Cleo_Exploitation_JAVA_Payloads_Dec24_2 : FILE
{
meta:
= "Detects characteristics of JAVA files used during Cleo software exploitation (as reported by Huntress in December 2024) - file Proc"
= "Florian Roth"
= "bd575454-7fd0-566d-94e5-ec1368675108"
= "2024-12-10"
= "2024-12-12"
= "https://www.huntress.com/blog/threat-advisory-oh-no-cleo-cleo-software-actively-being-exploited-in-the-wild"
= "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/expl_cleo_dec24.yar#L247-L265"
= "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
= "1ba95af21bac45db43ebf02f87ecedde802c7de4d472f33e74ee0a5b5015a726"
= "2bb5eace09b832bf3ce296484f473c9c56f97b881ea17838408be6000cc6fcb1"
= 75
= 85
= "FILE"
strings:
$s1 = "Timeout getting pipe-data" ascii fullword
$s2 = "Ftprootpath" ascii fullword
$s3 = "Rest cmd=" ascii fullword
$s4 = "writeToProc" ascii fullword
condition:
uint16( 0 ) == 0xfeca and filesize < 30KB and 3 of them
}
Strings (4 patterns)
| Identifier | Type | Value | Modifiers |
|---|---|---|---|
| $s1 | text | "Timeout getting pipe-data" | ascii fullword |
| $s2 | text | "Ftprootpath" | ascii fullword |
| $s3 | text | "Rest cmd=" | ascii fullword |
| $s4 | text | "writeToProc" | ascii fullword |
Condition
uint16( 0 ) == 0xfeca and filesize < 30KB and 3 of themIn plain words (Heuristic)
- The file must be smaller than 30KB (a cheap guard that skips large files).
- At least 3 patterns in the rule must match.
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).
- 1ba95af21bac45db43ebf02f87ecedde802c7de4d472f33e74ee0a5b5015a726
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: bd575454-7fd0-566d-94e5-ec1368675108
Tags:FILE
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