Proxyweb

Overview

Trojan:Win32/Proxyweb is a type of malware that silently converts an infected endpoint into a proxy server or relay node for a larger botnet. Instead of stealing data or encrypting files, Proxyweb's primary goal is to monetize the victim's internet connection and IP address by selling it to other cybercriminals, who use it to hide the true origin of their malicious traffic (like credential stuffing, DDoS attacks, or spam campaigns).

Understanding Proxyweb (Proxy Botnets)
To an end-user, a Proxyweb infection might only manifest as a sluggish internet connection or unexplained bandwidth overage charges. For an enterprise security team, it represents a significant liability. If a corporate workstation is infected with Proxyweb, the company's IP address will be used to launch attacks against other organizations, potentially leading to the company's IP block being blacklisted by major threat intelligence feeds and service providers.

Execution and Relay Mechanics
Proxyweb is often distributed silently alongside bundled software, fake game cracks, or via drive-by downloads (`T1189`). Upon execution, it establishes persistence, often via Registry Run keys or Scheduled Tasks (`T1547.001`). The malware binds a local port on the infected machine and opens an encrypted connection to a Command and Control (C2) server, registering the machine's IP, geographic location, and bandwidth capacity with the botmaster (`T1071.001`). The C2 server then begins routing third-party traffic (often SOCKS4/SOCKS5 or HTTP proxy traffic) through the infected host (`T1090.003`). The infected machine receives requests from the attacker, forwards them to the target server, and sends the response back to the attacker, acting as a complete middleman.

Indicators of Compromise & Impact
The impact is network bandwidth exhaustion and severe reputational damage (IP blacklisting). Host-based IoCs include EDR alerts for anomalous processes binding listening ports, or unexpected modifications to the Windows Firewall to allow inbound connections. Network IoCs are highly visible: massive amounts of anomalous outbound traffic (often HTTP or HTTPS) to completely unrelated and diverse IP addresses, originating from a single workstation rather than a proxy server.

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:

• T1071.001: Implement web filtering and SSL/TLS inspection to detect malicious command and control (C2) traffic hiding in HTTP/HTTPS.

MITRE D3FEND™ Defensive Countermeasures

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

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_PROXYWEB_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Proxyweb"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "proxyweb" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Proxyweb (Trojan) Execution & Triage
id: 49877dcc-bd6c-5629-8e68-6dcbf19f2508
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Proxyweb 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/proxyweb
- 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.t1562_004
- attack.t1547_001
- attack.t1090_003
- 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_PROXYWEB_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Proxyweb 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 = "proxyweb" 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 network to immediately halt the illicit proxy traffic and stop the abuse of the corporate IP address.
2. Review firewall and network flow logs for the infected machine to determine the scope of the proxy activity (e.g., what external sites were being attacked through your network).
3. Run a full anti-malware scan to remove the Proxyweb executable and delete the associated persistence mechanisms and firewall rules.
4. Check major threat intelligence and spam blacklists (e.g., Spamhaus) to ensure the corporate external IP address has not been blacklisted, and request delisting if necessary.

What to Avoid

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

1. Do not ignore alerts from ISPs or external organizations claiming your IP address is attacking them; this is a classic symptom of a proxy botnet infection inside the perimeter.
2. Avoid allowing workstations to act as servers; enforce strict egress filtering at the firewall to block anomalous outbound ports commonly used by proxy malware.

References & External Analysis

• Search "proxyweb" on VirusTotal (External Analysis)
• Search "proxyweb" on Any.Run (Sandbox Sandbox)
• Search "proxyweb" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Trojan)

Explore other documented threats in the same operational category:

• Socks
• Alinaos
• Driverassist
• Confucius
• Aenjaris
• Ramnif
• Zboter
• Qqshou

Machine-readable

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