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 the 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.

Generated Detections (Boilerplate)

These YARA and Sigma rules are auto-generated based on the family name and aliases. They must be heavily tuned before deployment in a production environment.

YARA Rule

rule MALWARE_WIN_PROXYWEB {
    meta:
        description = "Detects Proxyweb (trojan)"
        author = "SystemHelpdesk Boilerplate Generator"
        date = "2026-07-06"
    strings:
        $s1 = "proxyweb" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

Sigma Rule

title: Suspicious Proxyweb Activity
id: 355a4d054d8b1e65628d8cf8c515a54d
status: experimental
description: Detects generic indicators of the proxyweb malware family.
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains:
            - "*proxyweb*"
    condition: selection
level: medium

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)

Frequently Asked Questions

Related Families (Category: trojan)

Explore other malware families in the same category:

• Perfectoptimizer
• Quasar
• Shiotob
• Shelma
• Mailspy

Machine-readable

Get this profile as JSON: https://jordanricky1604-ship-it.github.io/malware-families-catalog/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.