{
  "family": "sharer",
  "sample_count": 1,
  "category": "trojan",
  "description": "<h3>Executive Summary</h3>\nSharer (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.\n\n<h3>Infection Vector and Technical Capabilities</h3>\nThe 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).\n\nUpon execution, Sharer focuses on rapid, automated propagation:\n<ul>\n<li><strong>P2P Client Hijacking:</strong> The worm actively searches the infected system for the installation directories and shared folders of popular P2P clients.</li>\n<li><strong>Automated Seeding:</strong> 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.</li>\n<li><strong>Secondary Payloads:</strong> 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).</li>\n</ul>\n\n<h3>Threat Assessment</h3>\nWhile 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.\n\n<h3>Remediation and Eradication</h3>\n<ul>\n<li><strong>Network Blocking (P2P):</strong> 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).</li>\n<li><strong>Application Control:</strong> Enforce strict application whitelisting to prevent standard users from installing unauthorized P2P client software on corporate assets.</li>\n<li><strong>Endpoint Cleanup:</strong> 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.</li>\n</ul>",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [
    "Worm.P2P.Sharer",
    "Trojan.P2P",
    "Win32/Sharer"
  ],
  "enrichment_level": "insufficient_information",
  "faq": [],
  "faq_count": 0,
  "mitre_attack": [
    "T1566",
    "T1059",
    "T1105"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-07-01T17:22:16Z",
  "type": "Worm / P2P",
  "target_industries": [
    "Global / Opportunistic"
  ],
  "motivation": "Opportunistic",
  "threat_actors": [
    "Unknown / Cybercriminal"
  ],
  "target_geographies": [
    "Global"
  ]
}