PureZip

YARA detection rule by @bartblaze · MIT

Identifies ZIP files with a hidden file named '__.exe', as seen in a massive PureCrypt campaign in Q1 2024.

rule PureZip
{
    meta:
        id = "3irhYCOx5n1gPEoxWCpDiE"
        fingerprint = "c713faeaeb58701fd04353ef6fd17e4677da735318c43658d62242cd2ca3718d"
        version = "1.0"
        date = "2024-03-20"
        modified = "2024-03-20"
        status = "RELEASED"
        sharing = "TLP:CLEAR"
        source = "BARTBLAZE"
        author = "@bartblaze"
        description = "Identifies ZIP files with a hidden file named '__.exe', as seen in a massive PureCrypt campaign in Q1 2024."
        category = "MALWARE"
        malware = "Pure"
        malware_family= "INFOSTEALER"
        hash = "ff668ef41336749df82e897c36b1438da1a21b1816716b30183024a8b62342a2"

strings:
            $exe = {5F 5F 2E 65 78 65} 
condition:
    uint16(0) == 0x4b50 and $exe in (filesize-300..filesize)
}

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

963ddd01-9bd4-4e33-bfb7-00b61fe2bf6d

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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 ]]

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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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