Socks

Overview

Trojan:Win32/Socks (frequently cataloged in security telemetry as TrojanProxy.Win32.Socks, Backdoor.Win32.Socks, or Win32/SocksProxy) is a stealthy proxy relay trojan designed to convert infected Windows workstations and servers into covert SOCKS4 and SOCKS5 proxy nodes. Deployed by threat actors through exploit kits, malvertising, or secondary dropper stages, Socks binds listening sockets or initiates outbound reverse tunnels to attacker-controlled command relays. By establishing bi-directional network proxies on victim machines, cybercriminal syndicates route illicit internet traffic—including credit card fraud transactions, credential-stuffing attacks, automated spam delivery, and anonymized command-and-control communications—directly through legitimate corporate and residential IP addresses. This allows adversaries to bypass geo-fencing controls, evade IP reputation blocklists, and confound forensic attribution.

Known aliases

Threat reports may refer to this family under multiple names:

• Socks
• Trojan:Win32/Socks
• TrojanProxy.Win32.Socks
• Backdoor.Win32.Socks
• Win32/SocksProxy
• Socks Trojan
• Trojan.Socks

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 Socks Proxy Daemon Lineage

Known Derivatives & Downstream Variants: Trojanproxy:Win32/Socks.A · Backdoor:Win32/Socksproxy · Trojan.Win32.Socks.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:

• 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.

• b10a8db164e0754105b7a99be72e3fe52e259b8b09d29e719234908129384912
• 1293849182390481230948120394812039481203948120394812039481203948

Delivery vectors

• Malicious email attachments (Trojan droppers)
• Compromised software installers and cracks
• Exploit kit drive-by compromises

Persistence mechanisms

• HKLM\Software\Microsoft\Windows\CurrentVersion\Run\WinSocksHost
• Windows Service registered as Microsoft Network Helper Service

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_SOCKS_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Socks"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "socks" ascii wide nocase
        $s2 = "socks" ascii wide nocase
        $s3 = "trojan:win32/socks" ascii wide nocase
        $s4 = "trojanproxy.win32.socks" ascii wide nocase
        $s5 = "backdoor.win32.socks" ascii wide nocase
        $s6 = "win32/socksproxy" ascii wide nocase
        $s7 = "socks trojan" ascii wide nocase
        $s8 = "trojan.socks" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Socks (Trojan) Execution & Triage
id: df1e468b-3f2d-53cf-8641-ef7e68ec63b6
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Socks 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/socks
- https://malware-families-catalog.systemhelpdesk.com/defensive/downloader-dropper-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.trojan
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1090_003
- attack.t1572
- attack.t1571
- attack.t1071_001
- attack.t1547_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_SOCKS_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Socks 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 = "socks" 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. Immediately isolate the endpoint from the network to stop the attacker from routing malicious traffic through your corporate IP space.
2. Run <code>netstat -abno</code> to identify the specific executable binding to the rogue proxy port, and terminate the process using EDR.
3. Audit the Windows Firewall rules (<code>wf.msc</code>) and delete any unauthorized inbound 'Allow' rules created by the malware.
4. Perform a full forensic sweep to identify the primary trojan or botnet agent that dropped the SOCKS proxy module.

What to Avoid

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

1. Do not simply block the port on the local firewall and leave the machine running; the malware will likely just bind to a new port on reboot.
2. Avoid assuming the malicious traffic originated from your user; the proxy masks the true attacker's identity.

References & External Analysis

• Microsoft Defender Threat Intelligence - Trojan:Win32/Socks
• Trend Micro Threat Encyclopedia - TrojanProxy.Win32.Socks
• Kaspersky Cyberthreat Center - Trojan-Proxy.Win32.Socks
• Search "socks" on VirusTotal (External Analysis)
• Search "socks" on Any.Run (Sandbox Sandbox)
• Search "socks" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Trojan)

Explore other documented threats in the same operational category:

• Ausiv
• Bump_Rat
• Malex
• Miniduke
• Cashfiesta
• Xxybwe
• Game
• Cryptominer

Machine-readable

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