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apt_malware_win_freshfire

YARA detection rule by threatintel@volexity.com · See license at https://github.com/volexity/threat-intel/blob/main/LICENSE.txt

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.

import "pe"
rule apt_malware_win_freshfire: CozyLarch
{
    meta:
        author = "threatintel@volexity.com"
        date = "2021-05-27"
        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."
        hash = "ad67aaa50fd60d02f1378b4155f69cffa9591eaeb80523489a2355512cc30e8c"
        os = "win"
        os_arch = "all"
        reference = "https://www.volexity.com/blog/2021/05/27/suspected-apt29-operation-launches-election-fraud-themed-phishing-campaigns/"
        scan_context = "file"
        severity = "critical"
        last_modified = "2025-05-21T15:28:46Z"
        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*)
}

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

d790e02b-c883-4505-856f-7b303dd780fa

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Executable code, not a declarative rule

This submission is arbitrary [[ currentRule.format ? currentRule.format.toUpperCase() : '' ]] code, not a declarative detection rule — review it as you would any script before running it, and note that it cannot be safely aggregated or auto-executed alongside YARA/Sigma/Suricata/CRS rules.

Rejected pattern present

[[ reason ]]

What does this mean?

Format & documentation suggestions

Not a security issue — this rule is valid and was accepted as-is. These are optional fields/conventions its own format recommends, mainly affecting its quality score and how well it documents itself for other reviewers.

[[ reason ]]

What do these messages mean?

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

[[ currentRule.title ]]

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