MAL_PseudoManuscrypt_Dec_2021_1

YARA detection rule by Arkbird_SOLG

Detect PseudoManuscrypt loader dropped by the installer

rule MAL_PseudoManuscrypt_Dec_2021_1
{
    meta:
        description = "Detect PseudoManuscrypt loader dropped by the installer"
        author = "Arkbird_SOLG"
        date = "2021-12-16"
        reference = "https://ics-cert.kaspersky.com/media/Kaspersky-ICS-CERT-PseudoManuscrypt-a-mass-scale-spyware-attack-campaign-En.pdf"
        hash1 = "19627bcee38a4ca5ae9a60c71ee7a2e388ba99fb8b229700a964a084db236e1f"
        hash2 = "be94df270acfc8e5470fa161b808d0de1c9e85efeeff4a5d82f5fd09629afa8e"
        hash3 = "de965e33dff58cf011106feacef2f804d9e35d00b8b5ff7064e5b7afee46d72c"
        hash4 = "e32899bef78f6af4a155f738298e042f72fe5e643ec934f8778180f71e511727"
        tlp = "white"
        adversary = "-"
    strings:
        $s1 = { 53 4f 46 54 57 41 52 45 5c 4d 69 63 72 6f 73 6f 66 74 5c 43 72 79 70 74 6f 67 72 61 70 68 79 00 7b 47 36 35 37 59 53 30 36 2d 30 31 36 44 2d 34 43 30 52 2d 36 30 32 32 2d 46 47 45 32 43 33 32 32 36 36 37 46 7d 00 00 4d 61 63 68 69 6e 65 47 75 69 64 }
        $s2 = { 45 ?? 5c 43 4c 53 c7 45 ?? 49 44 5c 25 c7 45 ?? 73 00 00 00 c7 45 ?? 47 6c 6f 62 c7 45 ?? 61 6c }
        $s3 = { 56 69 72 74 c7 [2-4] 75 61 6c 41 c7 [2-4] 6c 6c 6f 63 ff 15 }
        $s4 = { 4c 6f 61 64 65 72 2e 64 6c 6c 00 53 65 72 76 69 63 65 4d 61 69 6e }
        $s5 = { 2e 72 73 72 63 24 30 31 00 00 00 00 a0 ?? 00 00 ?? 04 00 00 2e 72 73 72 63 24 30 32 }
    condition:
       uint16(0) == 0x5A4D and filesize > 3KB and filesize < 30KB and all of ($s*) 
}

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

ebf0dd6b-a9c0-4e87-b260-65c940d15002

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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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