EXE_Trojan_RomCom_Feb2024

YARA detection rule by Yashraj Solanki - Cyber Threat Intelligence Analyst at Bridewell · Unknown

Rule EXE_Trojan_RomCom_Feb2024 (No description metadata provided).

import "math"
import "pe"
rule EXE_Trojan_RomCom_Feb2024 {
    meta:
        Description = "Detects malware used by RomCom Threat Actor based on high resource entropy and other PE Import characteristics"
        author = "Yashraj Solanki - Cyber Threat Intelligence Analyst at Bridewell"
        Credits = "Is Now on VT for notificaiton on the availiblity of the malware sample on Twitter"
        Reference = "https://twitter.com/Now_on_VT/status/1752598052819415467"
        Hash = "1a7bb878c826fe0ca9a0677ed072ee9a57a228a09ee02b3c5bd00f54f354930f"
        date = "2024-02-01"
        yarahub_author_twitter = "@RustyNoob619"
        yarahub_reference_md5 = "f4959e947cee62a3fa34d9c191dd9351"
        yarahub_uuid = "23c18112-c9f3-427f-b479-056868c6a1f7"
        yarahub_license = "CC0 1.0"
        yarahub_rule_matching_tlp = "TLP:WHITE"
        yarahub_rule_sharing_tlp = "TLP:WHITE"
        malpedia_family = "win.romcom_rat"
    
    condition:
        pe.imphash() == "48b74a60787e54387294ac125b7ed128" 
        or (pe.number_of_resources == 3
        and pe.number_of_imported_functions > 100
        and for any resource in pe.resources:
        (math.entropy(resource.offset, resource.length) > 7.9 and resource.type == 3 )
        and pe.imports("KERNEL32.dll", "GetStartupInfoW")
        and pe.imports("KERNEL32.dll", "GetPhysicallyInstalledSystemMemory")
        and pe.imports("KERNEL32.dll", "InitializeCriticalSectionAndSpinCount")
        and pe.imports("NETAPI32.dll", "NetUserGetInfo")
        and pe.imports("ADVAPI32.dll", "LookupAccountNameW")
        and pe.imports("ADVAPI32.dll", "ChangeServiceConfig2W"))
             
 }

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

3d66199f-6bb0-47cb-baf0-be37953f9dce

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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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