Sharer
Overview
Executive Summary
Sharer (often detected as Worm.P2P.Sharer or Trojan.Sharer) represents a family of legacy worms specifically engineered to exploit the decentralized nature of Peer-to-Peer (P2P) file-sharing networks (such as eMule, Kazaa, Limewire, or BitTorrent). By masquerading as highly desirable, pirated content, Sharer tricks users into downloading and executing the malware, subsequently hijacking the user's P2P client to distribute itself to thousands of other victims.Infection Vector and Technical Capabilities
The primary infection vector is entirely reliant on user deception. The malware is uploaded to P2P networks with enticing, frequently changing filenames (e.g., "Windows_10_Crack.exe", "Photoshop_Keygen.exe", or titles of recently released movies/music). Upon execution, Sharer focuses on rapid, automated propagation:- P2P Client Hijacking: The worm actively searches the infected system for the installation directories and shared folders of popular P2P clients.
- Automated Seeding: Once the shared folders are located, the worm copies its executable into them, often generating hundreds of copies with dynamically generated, clickbait filenames. It then forces the P2P client to actively "seed" (upload) these malicious files to the broader network.
- Secondary Payloads: While the primary function is propagation, Sharer worms frequently act as loaders, downloading secondary payloads such as Adware (to generate pay-per-install revenue for the author) or Info-stealers (to harvest credentials).
Threat Assessment
While the prominence of traditional P2P networks has declined in favor of streaming services, the tactic remains viable on modern torrent networks. A Sharer infection exposes the corporate network to significant legal liability (due to the active distribution of pirated/malicious files) and serves as an open door for more severe, secondary malware infections.Remediation and Eradication
- Network Blocking (P2P): The most effective defense is perimeter-level blocking. Enterprise firewalls and web gateways must be configured to strictly block the protocols and ports associated with P2P file sharing (e.g., BitTorrent).
- Application Control: Enforce strict application whitelisting to prevent standard users from installing unauthorized P2P client software on corporate assets.
- Endpoint Cleanup: Utilize enterprise anti-malware solutions to scan for and remove the Sharer executables, paying special attention to user profile directories (like `%AppData%`) where the worm often hides its payload and generated copies.
Known aliases
Threat reports may refer to this family under multiple names:
MITRE ATT&CK Techniques
This family has been observed using the following ATT&CK techniques: T1566 T1059 T1105
Tactical Mitigations
Based on the techniques used by this family, consider the following defensive strategies:
- T1059: Restrict execution of scripting languages such as PowerShell, VBScript, or Python to authorized administrators. Enforce Script Block Logging.
- T1105: Implement network intrusion detection systems (NIDS) and host-based firewalls to block unauthorized inbound or outbound file transfers.
- T1566: Implement email filtering, Sender Policy Framework (SPF), DomainKeys Identified Mail (DKIM), and DMARC. Conduct user phishing awareness training.
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_SHARER {
meta:
description = "Detects Sharer (trojan)"
author = "SystemHelpdesk Boilerplate Generator"
date = "2026-07-06"
strings:
$s1 = "sharer" ascii wide nocase
$s2 = "worm.p2p.sharer" ascii wide nocase
$s3 = "trojan.p2p" ascii wide nocase
$s4 = "win32/sharer" ascii wide nocase
condition:
uint16(0) == 0x5a4d and any of them
}Sigma Rule
title: Suspicious Sharer Activity
id: 13db22299cf01774e4a9281808eab1d3
status: experimental
description: Detects generic indicators of the sharer malware family.
logsource:
category: process_creation
product: windows
detection:
selection:
Image|endswith:
- '\cmd.exe'
- '\powershell.exe'
CommandLine|contains:
- "*sharer*"
- "*worm.p2p.sharer*"
- "*trojan.p2p*"
- "*win32/sharer*"
condition: selection
level: mediumReferences & External Analysis
- Search "sharer" on VirusTotal (External Analysis)
Frequently Asked Questions
How do I remove the Sharer Trojan from Windows?
Manual removal of Sharer is highly discouraged as it may leave persistence mechanisms intact. We recommend disconnecting the device from the internet and utilizing a professional incident response service or enterprise-grade EDR software to conduct a full forensic sweep.
Is Sharer a virus or a Trojan?
Sharer is classified as a Trojan. Unlike traditional viruses that infect files, modern malware like Sharer typically operates as a standalone payload designed to compromise systems, steal data, or deploy secondary stage implants.
What are the main symptoms of a Sharer infection?
Symptoms of Sharer can include unexpected system slowness, unauthorized outbound network traffic to unknown IP addresses, disabled security software, and suspicious background processes running from AppData or Temp directories.
Related Families (Category: trojan)
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Protect Your Network Against Trojans
Want to prevent Sharer and similar threats from compromising your organization? Read our comprehensive defensive guide: Banking Trojan Protection.
Machine-readable
Get this profile as JSON: https://jordan123234-malware-families-explorer.static.hf.space/api/sharer.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.