YARA · SEKOIA.IO Community
SEKOIA_Loader_Win_Jennlog
Jennlog loader used to deliver the Apostle ransomware
- Author
- Sekoia.io
- Date
- 2021-10-04
- Modified
- 2024-12-19
- Score / Quality
- 75 / 80
What this rule detects
Jennlog loader used to deliver the Apostle ransomware
Associated malware family: Jennlog.
Targets: Windows PE.
It has no patterns: the condition alone decides (modules, file properties or other rules). YARA modules used: pe, hash.
YARA-X says: warning[deprecated_field]: field `number_of_sections` is deprecated
Summary generated from the rule's metadata and condition.
Rule source
Includes the imports needed to compile it on its own.
import "pe"
import "hash"
rule SEKOIA_Loader_Win_Jennlog
{
meta:
= "Jennlog loader used to deliver the Apostle ransomware"
= "Sekoia.io"
= "a69088e5-207f-494f-876b-766b8050e8c2"
= "2021-10-04"
= "2024-12-19"
= "https://www.sentinelone.com/labs/new-version-of-apostle-ransomware-reemerges-in-targeted-attack-on-higher-education/"
= "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/yara_rules/loader_win_jennlog.yar#L4-L24"
= "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/LICENSE.md"
= "0ffcd1f35570b28a1bd6f9a0361f8f921942f7345dcb2896fc092bb92f7d4d6d"
= 75
= 80
= ""
= "1.0"
= "TLP:CLEAR"
condition:
pe.timestamp== 3140259112 or for any i in ( 0 .. pe.number_of_sections -1 ) : ( hash.md5 ( pe.sections [ i ] . raw_data_offset , pe.sections [ i ] . raw_data_size ) == "4c4577276ff0323d9aedcc39ecf2c964" ) or for any i in ( 0 .. pe.number_of_resources -1 ) : ( hash.sha256 ( pe.resources [ i ] . offset , pe.resources [ i ] . length ) == "8476a7fca587f1e5d3ae076293b9fbcccbebc4bd4f7b783228ad5da39305a3d9" )
}
Condition
pe.timestamp== 3140259112 or for any i in ( 0 .. pe.number_of_sections -1 ) : ( hash.md5 ( pe.sections [ i ] . raw_data_offset , pe.sections [ i ] . raw_data_size ) == "4c4577276ff0323d9aedcc39ecf2c964" ) or for any i in ( 0 .. pe.number_of_resources -1 ) : ( hash.sha256 ( pe.resources [ i ] . offset , pe.resources [ i ] . length ) == "8476a7fca587f1e5d3ae076293b9fbcccbebc4bd4f7b783228ad5da39305a3d9" )In plain words (Heuristic)
- A for-loop checks a property over several matches or items.
- Uses the pe module.
- Uses the hash module.
- Compares a hash of the file or a part of it.
- Checks PE sections (names, count or properties).
Test this rule in your browser
Drop a file to scan it with this rule using YARA-X compiled to WebAssembly. Nothing is uploaded.
Licence & attribution
Author: Sekoia.io
Source repository: SEKOIA.IO Community @ a438a5901a
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: a69088e5-207f-494f-876b-766b8050e8c2
Metadata
| version | 1.0 |
|---|---|
| classification | TLP:CLEAR |
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