YARA · Volexity threat-intel
VOLEXITY_Apt_Malware_Win_Freshfire
The FRESHFIRE malware family. The malware acts as a downloader, pulling down an encrypted snippet of code from a remote source, executing it, and deleting it from the remote server.
- Author
- threatintel@volexity.com
- Date
- 2021-05-27
- Modified
- 2025-05-21
- Score / Quality
- 75 / 80
What this rule detects
The FRESHFIRE malware family. The malware acts as a downloader, pulling down an encrypted snippet of code from a remote source, executing it, and deleting it from the remote server.
Targets: Windows PE.
It defines 5 patterns (5 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 VOLEXITY_Apt_Malware_Win_Freshfire : COZYLARCH FILE
{
meta:
= "The FRESHFIRE malware family. The malware acts as a downloader, pulling down an encrypted snippet of code from a remote source, executing it, and deleting it from the remote server."
= "threatintel@volexity.com"
= "050b8e61-139a-5ff5-998a-7de67c9975bf"
= "2021-05-27"
= "2025-05-21"
= "https://www.volexity.com/blog/2021/05/27/suspected-apt29-operation-launches-election-fraud-themed-phishing-campaigns/"
= "https://github.com/volexity/threat-intel/blob/3a9d0b52459877ee866a9a0ba06e60059b778c77/2021/2021-05-27 - Suspected APT29 Operation Launches Election Fraud Themed Phishing Campaigns/indicators/yara.yar#L55-L87"
= "https://github.com/volexity/threat-intel/blob/3a9d0b52459877ee866a9a0ba06e60059b778c77/LICENSE.txt"
= "ad67aaa50fd60d02f1378b4155f69cffa9591eaeb80523489a2355512cc30e8c"
= "69cd73f5812ba955c1352fb1552774d5cf49019d6b65a304fd1e33f852e678ba"
= 75
= 80
= "COZYLARCH, FILE"
= "win"
= "all"
= "file"
= "critical"
= "See license at https://github.com/volexity/threat-intel/blob/main/LICENSE.txt"
= 5459
= 9
strings:
$uniq1 = "UlswcXJJWhtHIHrVqWJJ"
$uniq2 = "gyibvmt\x00"
$path1 = "root/time/%d/%s.json"
$path2 = "C:\\dell.sdr"
$path3 = "root/data/%d/%s.json"
condition:
(pe.number_of_exports == 1 and pe.exports ( "WaitPrompt" ) ) or any of ( $uniq* ) or 2 of ( $path* )
}
Strings (5 patterns)
| Identifier | Type | Value | Modifiers |
|---|---|---|---|
| $uniq1 | text | "UlswcXJJWhtHIHrVqWJJ" | |
| $uniq2 | text | "gyibvmt\x00" | |
| $path1 | text | "root/time/%d/%s.json" | |
| $path2 | text | "C:\\dell.sdr" | |
| $path3 | text | "root/data/%d/%s.json" |
Condition
(pe.number_of_exports == 1 and pe.exports ( "WaitPrompt" ) ) or any of ( $uniq* ) or 2 of ( $path* )In plain words (Heuristic)
- At least one pattern in ( $uniq* ) must match.
- At least 2 patterns in ( $path* ) must match.
- Uses the pe module.
- 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).
- ad67aaa50fd60d02f1378b4155f69cffa9591eaeb80523489a2355512cc30e8c
Licence & attribution
Author: threatintel@volexity.com
Source repository: Volexity threat-intel @ 3a9d0b5245
Licence: BSD 2-Clause License (stated in the rule's own meta)
“See license at https://github.com/volexity/threat-intel/blob/main/LICENSE.txt”
Copyright notice: Copyright 2022 by Volexity, Inc.
Mirrored via YARA Forge 20260927, which prefixes rule names with the source and adds normalised meta fields.
Rule id: 050b8e61-139a-5ff5-998a-7de67c9975bf
Metadata
| os | win |
|---|---|
| os_arch | all |
| scan_context | file |
| severity | critical |
| rule_id | 5459 |
| version | 9 |
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