APT_Dropper_Win64_TEARDROP_2

YARA detection rule by FireEye · NOASSERTION

This rule is intended match specific sequences of opcode found within TEARDROP, including those that decode the embedded payload. TEARDROP is a memory only dropper that can read files and registry keys, XOR decode an embedded payload, and load the payload into memory. TEARDROP persists as a Windows service and has been observed dropping Cobalt Strike BEACON into memory.

rule APT_Dropper_Win64_TEARDROP_2
{
    meta:
        author = "FireEye"
        description = "This rule is intended match specific sequences of opcode found within TEARDROP, including those that decode the embedded payload. TEARDROP is a memory only dropper that can read files and registry keys, XOR decode an embedded payload, and load the payload into memory. TEARDROP persists as a Windows service and has been observed dropping Cobalt Strike BEACON into memory."
        source = "https://github.com/fireeye/sunburst_countermeasures/blob/main/rules/TEARDROP/yara/APT_Dropper_Win64_TEARDROP_2.yar"
    
    strings:
        $loc_4218FE24A5 = { 48 89 C8 45 0F B6 4C 0A 30 }
        $loc_4218FE36CA = { 48 C1 E0 04 83 C3 01 48 01 E8 8B 48 28 8B 50 30 44 8B 40 2C 48 01 F1 4C 01 FA }
        $loc_4218FE2747 = { C6 05 ?? ?? ?? ?? 6A C6 05 ?? ?? ?? ?? 70 C6 05 ?? ?? ?? ?? 65 C6 05 ?? ?? ?? ?? 67 }
        $loc_5551D725A0 = { 48 89 C8 45 0F B6 4C 0A 30 48 89 CE 44 89 CF 48 F7 E3 48 C1 EA 05 48 8D 04 92 48 8D 04 42 48 C1 E0 04 48 29 C6 }
        $loc_5551D726F6 = { 53 4F 46 54 57 41 52 45 ?? ?? ?? ?? 66 74 5C 43 ?? ?? ?? ?? 00 }
    condition:
        (uint16(0) == 0x5A4D and uint32(uint32(0x3C)) == 0x00004550) and any of them
}

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

1fcf22c4-d287-4cc2-a76b-7544d8415146

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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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