{
  "family": "pyme",
  "sample_count": 1,
  "category": "ransomware",
  "description": "<h3>Executive Summary</h3>\nPyme is a malicious program that exhibits characteristics of both a Trojan and a Worm. It is designed to covertly infiltrate Windows systems, establish a persistent backdoor, and then aggressively attempt to propagate itself across local networks or via removable media, creating a disruptive and potentially widespread security incident.\n\n<h3>Infection Vector and Technical Capabilities</h3>\nPyme often infiltrates networks initially through malicious email attachments or when a user connects an already infected USB drive to a corporate workstation.\n\nUpon execution, Pyme focuses on persistence and propagation:\n<ul>\n<li><strong>Worm-like Propagation:</strong> Pyme actively scans the local subnet for open, unauthenticated file shares (SMB) or exploits legacy vulnerabilities to copy its executable laterally. It will also aggressively infect any connected removable media (USB drives), hiding legitimate files and replacing them with malicious shortcuts to facilitate further spread.</li>\n<li><strong>System Modification and Persistence:</strong> To ensure it runs every time the system boots, Pyme modifies the Windows Registry (e.g., adding entries to `HKCU\\Software\\Microsoft\\Windows\\CurrentVersion\\Run`). It may also disable built-in security features like Windows Defender or the Task Manager to protect itself from termination.</li>\n<li><strong>Backdoor Functionality:</strong> While spreading, Pyme often opens a covert backdoor, allowing remote attackers to issue commands, download secondary malware, or exfiltrate basic system data.</li>\n</ul>\n\n<h3>Threat Assessment</h3>\nA Pyme infection is highly disruptive. Its worm-like propagation capabilities can rapidly saturate a local network, causing significant downtime and overwhelming IT helpdesks. The backdoor functionality also presents a serious risk of data theft or the deployment of secondary, more destructive payloads like ransomware.\n\n<h3>Incident Response and Remediation</h3>\n<ul>\n<li><strong>Immediate Network Segmentation:</strong> Isolate infected subnets immediately to halt the worm's lateral movement and prevent the infection of mapped network drives.</li>\n<li><strong>Comprehensive Antivirus Sweep:</strong> Deploy an enterprise-grade anti-malware solution across the affected subnets to identify, quarantine, and remove the Pyme executable and its associated registry keys.</li>\n<li><strong>Removable Media Policy Review:</strong> Pyme's reliance on USB propagation strongly suggests that the organization's policies regarding removable media are either lacking or unenforced. Consider disabling USB storage access via Group Policy to prevent future outbreaks.</li>\n</ul>",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [
    "Worm.Pyme",
    "Trojan.Pyme",
    "Win32/Pyme"
  ],
  "enrichment_level": "insufficient_information",
  "faq": [],
  "faq_count": 0,
  "mitre_attack": [
    "T1059",
    "T1091",
    "T1547.001",
    "T1562.001"
  ],
  "cisa_advisory": null,
  "last_updated": "2026-07-02T07:20:09Z",
  "type": "Trojan / Worm",
  "target_industries": [
    "Global / Opportunistic"
  ],
  "motivation": "Opportunistic",
  "threat_actors": [
    "Unknown / Cybercriminal"
  ],
  "target_geographies": [
    "Global"
  ]
}