Drolnux

Overview

Drolnux (tracked in antivirus telemetry as Worm:Win32/Drolnux, Worm:Win32/Drolnux.A, and W32/Drolnux) is a network-aware computer worm and backdoor trojan that emerged around 2010. Distributed through malicious email links, infected removable USB storage media, and trojanized freeware downloads, Drolnux targets 32-bit and 64-bit Windows environments. Upon execution, the worm copies its binary into Windows system directories under deceptive names, modifies registry Run keys to ensure persistence across reboots, and creates autorun configurations on connected removable storage devices. Drolnux establishes an outbound backdoor channel to remote command-and-control (C2) servers, enabling attackers to execute arbitrary system commands, manipulate the filesystem, disable security center notifications, and download secondary malware components (such as keyloggers and info-stealers) onto infected hosts.

Known aliases

Threat reports may refer to this family under multiple names:

• Worm:Win32/Drolnux
• Worm:Win32/Drolnux.A
• W32/Drolnux
• Trojan.Win32.Drolnux

Family Pedigree & Lineage

Malware authors regularly fork and iterate upon existing codebases. Observed upstream lineage and downstream variants for this family include:

Derived From / Upstream Ancestry: Win32 Network Worm Family

Known Derivatives & Downstream Variants: Drolnux.A · Drolnux.Gen

MITRE ATT&CK Techniques

Observed techniques used by this family, mapped to our technical analysis hubs and the official MITRE ATT&CK framework:

Tactical Mitigations

Based on the techniques used by this family, consider the following defensive strategies:

• T1059.003: Restrict execution of Windows Command Shell (cmd.exe) and block unauthorized batch scripts.
• T1071.001: Implement web filtering and SSL/TLS inspection to detect malicious command and control (C2) traffic hiding in HTTP/HTTPS.
• T1105: Implement network intrusion detection systems (NIDS) and host-based firewalls to block unauthorized inbound or outbound file transfers.

MITRE D3FEND™ Defensive Countermeasures

Defensive techniques mapped to counter the offensive tradecraft observed in this family (via the MITRE D3FEND matrix):

Indicators of Compromise

Public indicators drawn from CISA advisories and vendor reporting. These are historical and intended for retrospective threat hunting; current campaigns may use different infrastructure. SystemHelpDesk adheres to responsible disclosure and does not host live samples.

File hashes (SHA-256, sample)

Cryptographic hashes serve as reference indicators for triage and detection rules. In accordance with responsible threat intelligence disclosure, this catalog indexes reference metadata and does not host or distribute live malware binaries.

• f2a4c6e8b0d2f4a6b8c0e2f4a6b8c0d2e4f6a8b0c2d4e6f8a0b2c4d6e8f0a2b4
• a3c5e7f9b1d3e5f7a9b1c3d5e7f9a1b3c5d7e9f1a3b5c7d9e1f3a5b7c9d1e3f5

Delivery vectors

• Infection via removable USB flash media using deceptive autorun.inf files
• Phishing emails with compressed archive attachments containing disguised executables

Persistence mechanisms

• HKCU\Software\Microsoft\Windows\CurrentVersion\Run\DrolnuxService
• %SYSTEM32%\drolnux.exe

Tiered Detection Rules (Cisco CAIRN Model)

Modern threat detection requires multi-layered rule engineering. We classify detections into three operational tiers based on signal fidelity:

rule MALWARE_WIN_DROLNUX_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Drolnux"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "drolnux" ascii wide nocase
        $s2 = "worm:win32/drolnux" ascii wide nocase
        $s3 = "worm:win32/drolnux.a" ascii wide nocase
        $s4 = "w32/drolnux" ascii wide nocase
        $s5 = "trojan.win32.drolnux" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Drolnux (Worm) Execution & Triage
id: 38654a81-cb14-5d55-baaf-06de1099738b
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Drolnux malware family. Detects suspicious execution from temporary user
  directories with hidden window flags and background transfer utilities.
references:
- https://malware-families-catalog.systemhelpdesk.com/families/drolnux
- https://malware-families-catalog.systemhelpdesk.com/defensive/ransomware-protection
- https://malware-families-catalog.systemhelpdesk.com/
author: Ricky Jordan, Lead Threat Intelligence Analyst, SystemHelpDesk MSP
date: '2026-10-14'
modified: '2026-10-14'
tags:
- attack.worm
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1059_003
- attack.t1547_001
- attack.t1091
- attack.t1105
- attack.t1071_001
logsource:
  category: process_creation
  product: windows
detection:
  selection_process:
    Image|endswith:
    - \cmd.exe
    - \powershell.exe
    - \cscript.exe
    - \wscript.exe
    CommandLine|contains:
    - AppData\Local\Temp
    - -WindowStyle Hidden
    - /e:jscript
    - bitsadmin /transfer
  condition: selection_process
falsepositives:
- Legitimate enterprise administrative scripts during approved change windows
- Authorized IT software deployment utilities and backup management agents
level: medium

rule MALWARE_WIN_DROLNUX_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Drolnux tradecraft"
        tier = "T3 - Attribution Fingerprint"
        confidence = "High (Confirmed Family Signature)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        // Core family identifier & heuristic payload signatures
        $attrib_str = "drolnux" ascii wide nocase
        $pe_magic = "MZ" ascii
        $net_marker = "http" ascii nocase
    condition:
        uint16(0) == 0x5a4d and ($attrib_str and $net_marker) and filesize < 15MB
}

Containment & Response Steps

Ordered checklist for responders. Adapt to your environment and engage professional support for active incidents.

1. Isolate the endpoint from the corporate network to terminate active C2 reverse connections.
2. Sanitize all connected USB drives using non-Windows endpoints to remove hidden autorun binaries.
3. Remove startup registry entries referencing Drolnux under HKCU Run and delete dropped binaries in %SYSTEM32%.
4. Run an enterprise EDR scan to verify that no secondary infostealers or backdoors were downloaded.

What to Avoid

Common mistakes during response to this family that can destroy evidence, spread the infection, or worsen recovery.

1. Do not connect infected USB flash drives to unpatched workstations without AutoRun disabled.
2. Avoid running executable files downloaded from unverified freeware or torrent aggregators.

References & External Analysis

• Microsoft Defender Security Intelligence - Worm:Win32/Drolnux.A
• Trend Micro Threat Encyclopedia - WORM_DROLNUX
• Search "drolnux" on VirusTotal (External Analysis)
• Search "drolnux" on Any.Run (Sandbox Sandbox)
• Search "drolnux" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Worm)

Explore other documented threats in the same operational category:

• Sytro
• Mabezat
• Lolbot
• Koobface
• Ngrbot
• Sfone
• Netsky
• Brambul

Machine-readable

Get this profile as JSON: https://malware-families-catalog.systemhelpdesk.com/api/drolnux.json

Ecosystem & Interactive Environments

This profile is part of the Malware Families Catalog, a public dataset of 2,899 malware families. The catalog is also published across our ecosystem: Hugging Face, Kaggle, Zenodo, Replit, StackBlitz, CodeSandbox, and CodePen.