Benjamin

Overview

Benjamin (cataloged across antivirus vendors as Worm:Win32/Benjamin.A, W32.Benjamin.Worm, and P2P-Worm.Win32.Benjamin) is an infamous legacy peer-to-peer (P2P) network worm first identified in 2002. Specifically engineered to exploit decentralized file-sharing ecosystems—most notably KaZaA, Grokster, and the FastTrack network—Benjamin propagates by turning infected endpoints into high-volume distribution hubs for the worm. Upon initial execution, typically disguised as a cracked software utility, popular game patch, or multimedia archive, Benjamin copies its core executable into the Windows System folder and secures persistence through the Windows Registry Run key. It then scans local storage for designated P2P shared folders (such as 'My Shared Folder'). Once identified, the worm duplicates itself thousands of times into the shared directory, dynamically forging enticing filenames that match the most frequently queried search terms across the P2P network, exhausting local disk storage and launching distributed denial-of-service (DoS) traffic against targeted Spanish commercial servers.

Known aliases

Threat reports may refer to this family under multiple names:

• Worm:Win32/Benjamin.A
• W32.Benjamin.Worm
• P2P-Worm.Win32.Benjamin
• I-Worm.Benjamin
• W32/Benjamin.worm

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: P2P Network Worm Architecture · Fasttrack Shared Folder Flooder

Known Derivatives & Downstream Variants: Benjamin.A · Benjamin.B · Benjamin!Rfn

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:

• T1036.004: Monitor for executable files running from unusual paths or with deceptive names. Use EDR to detect process masquerading.

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.

• c1a3e5b7d9f1a3c5e7b9d1f3a5c7e9b1d3f5a7c9e1b3d5f7a9c1e3b5d7f9a1c3
• d2b4f6a8c0e2b4d6f8a0c2e4b6d8f0a2c4e6b8d0f2a4c6e8b0d2f4a6c8e0b2d4

Delivery vectors

• Deceptive executable downloads on FastTrack and KaZaA P2P file-sharing networks
• Masqueraded media and game crack files

Persistence mechanisms

• HKCU\Software\Microsoft\Windows\CurrentVersion\Run\explorer32
• %WINDIR%\system\explorer32.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_BENJAMIN_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Benjamin"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "benjamin" ascii wide nocase
        $s2 = "worm:win32/benjamin.a" ascii wide nocase
        $s3 = "w32.benjamin.worm" ascii wide nocase
        $s4 = "p2p-worm.win32.benjamin" ascii wide nocase
        $s5 = "i-worm.benjamin" ascii wide nocase
        $s6 = "w32/benjamin.worm" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Benjamin (Worm) Execution & Triage
id: ba74af47-4fc7-515e-99a7-362f20ae25f9
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Benjamin 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/benjamin
- 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.t1204_002
- attack.t1547_001
- attack.t1036_004
- attack.t1083
- attack.t1498
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_BENJAMIN_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Benjamin 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 = "benjamin" 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. Terminate active P2P client software (KaZaA, eMule, torrent clients) immediately to halt worm distribution.
2. Inspect designated P2P shared folders and delete thousands of identically sized generated executable files.
3. Audit HKCU and HKLM Registry Run keys to remove unauthorized worm startup keys (e.g., explorer32).
4. Execute a full endpoint antivirus scan to detect and remove the root worm dropper from the Windows directory.

What to Avoid

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

1. Do not execute software setups, cracks, or media files downloaded from unverified peer-to-peer file-sharing networks.
2. Avoid sharing root directories or unmonitored folders on peer-to-peer file-sharing applications.

References & External Analysis

• Microsoft Defender Security Intelligence - Worm:Win32/Benjamin
• F-Secure Threat Description - W32/Benjamin.worm
• Kaspersky Threat Intelligence - P2P-Worm.Win32.Benjamin
• Search "benjamin" on VirusTotal (External Analysis)
• Search "benjamin" on Any.Run (Sandbox Sandbox)
• Search "benjamin" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Worm)

Explore other documented threats in the same operational category:

• Lolbot
• Brambul
• Vbs_Worm_Generator
• Conficker
• Blasterx
• Drolnux
• Mogoogwi
• Sasser

Machine-readable

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