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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.

APT / threat actorVolexity threat-intelBSD 2-Clause LicenseCompiles with YARA-X
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.

apt-malware-win-freshfire.yarBSD 2-Clause License
import "pe"

rule VOLEXITY_Apt_Malware_Win_Freshfire : COZYLARCH FILE
{
	meta:
		description = "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"
		id = "050b8e61-139a-5ff5-998a-7de67c9975bf"
		date = "2021-05-27"
		modified = "2025-05-21"
		reference = "https://www.volexity.com/blog/2021/05/27/suspected-apt29-operation-launches-election-fraud-themed-phishing-campaigns/"
		source_url = "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"
		license_url = "https://github.com/volexity/threat-intel/blob/3a9d0b52459877ee866a9a0ba06e60059b778c77/LICENSE.txt"
		hash = "ad67aaa50fd60d02f1378b4155f69cffa9591eaeb80523489a2355512cc30e8c"
		logic_hash = "69cd73f5812ba955c1352fb1552774d5cf49019d6b65a304fd1e33f852e678ba"
		score = 75
		quality = 80
		tags = "COZYLARCH, FILE"
		os = "win"
		os_arch = "all"
		scan_context = "file"
		severity = "critical"
		license = "See license at https://github.com/volexity/threat-intel/blob/main/LICENSE.txt"
		rule_id = 5459
		version = 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)

IdentifierTypeValueModifiers
$uniq1text"UlswcXJJWhtHIHrVqWJJ"
$uniq2text"gyibvmt\x00"
$path1text"root/time/%d/%s.json"
$path2text"C:\\dell.sdr"
$path3text"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.

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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).

  • 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.

Original rule

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

oswin
os_archall
scan_contextfile
severitycritical
rule_id5459
version9

Tags:COZYLARCHFILE