SUSP_OBF_NET_ConfuserEx_Packer_Jan24

YARA detection rule by Jonathan Peters · Unknown

Detects binaries packed with ConfuserEx compression packer. This feature compresses and encrypts the actual image into a stub that unpacks and loads the original image on runtime.

rule SUSP_OBF_NET_ConfuserEx_Packer_Jan24 {
    meta:
        description = "Detects binaries packed with ConfuserEx compression packer. This feature compresses and encrypts the actual image into a stub that unpacks and loads the original image on runtime."
        author = "Jonathan Peters"
        date = "2024-01-09"
        reference = "https://github.com/yck1509/ConfuserEx/tree/master"
        hash = "2570bd4c3f564a61d6b3d589126e0940af27715e1e8d95de7863579fbe25f86f"
        score = 70
        yarahub_uuid = "a001daa4-f4d4-4059-92c9-7f4c5e2670df"
        yarahub_license = "CC BY 4.0"
        yarahub_rule_matching_tlp = "TLP:WHITE"
        yarahub_rule_sharing_tlp = "TLP:WHITE"
        yarahub_reference_md5 = "124e4c576f65f69021d23534b5d19d95"
    strings:
        $s1 = "GCHandle" ascii
        $s2 = "GCHandleType" ascii
        $op1 = "{ 5A 20 89 C0 3F 14 6A 5E [8-20] 5A 20 FB 56 4D 44 6A 5E 6D 9E }"
        $op2 = "{ 20 61 FF 6F 00 13 ?? 06 13 ?? 16 13 [10-20] 20 1F 3F 5E 00 5A}"
        $op3 = "{ 16 91 7E [3] 04 17 91 1E 62 60 7E [3] 04 18 91 1F 10 62 60 7E [3] 04 19 91 1F 18 62 }"
    condition:
        uint16 ( 0 ) == 0x5a4d and all of ( $s* ) and 2 of ( $op* )
}

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

fa8d3a46-b345-4a69-9c73-1e4f0ffebe59

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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

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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.

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

[[ currentRule.title ]]

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