{
  "family": "27d3e5bc",
  "sample_count": 1,
  "category": "ransomware",
  "description": "<h3>Executive Summary</h3>\n\"27d3e5bc\" (and similar purely hexadecimal strings) represents a strict, static hash-based detection signature utilized by antivirus engines. It does not identify a named malware family, but rather acts as a direct blocklist entry for a specific, known malicious file whose cryptographic hash (such as MD5, SHA-1, or SHA-256) matches the identifier perfectly.\n\n<h3>Static Detection and Technical Context</h3>\nUnlike heuristic detections (which analyze behavior), a hash-based detection like \"27d3e5bc\" means the endpoint protection platform (EPP) has encountered a file that is an exact, byte-for-byte match with a piece of malware that has been previously analyzed and definitively classified as malicious by the security vendor.\n\nThe implications of a hash-based detection include:\n<ul>\n<li><strong>Absolute Confidence:</strong> Hash detections have a near-zero false-positive rate. If a file triggers this alert, it is definitively malicious (assuming no hash collisions).</li>\n<li><strong>Zero Behavioral Context:</strong> While the detection is highly accurate, the identifier itself provides no context about what the malware actually does (e.g., whether it is an info-stealer, ransomware, adware, or a simple dropper).</li>\n<li><strong>High Evasion Vulnerability:</strong> Hash-based detections are easily bypassed by malware authors. Changing a single byte of the malicious executable (e.g., recompiling it, changing a timestamp, or adding a null byte) completely alters the resulting hash, rendering the static signature useless.</li>\n</ul>\n\n<h3>Threat Impact and Response</h3>\nWhile the alert confirms the presence of known malware, responders must treat it as a critical indicator that perimeter defenses were bypassed. The primary concern is whether the file was blocked pre-execution or if the hash was only detected during a post-execution sweep (e.g., during a scheduled scan).\n\n<h3>Incident Mitigation Strategy</h3>\n<ul>\n<li><strong>Verify Execution Status:</strong> Check the EDR logs immediately to determine if the EPP successfully blocked the file from executing (quarantined on write), or if it was only flagged after the process was already running.</li>\n<li><strong>Hash Enrichment Lookups:</strong> Take the full file hash associated with the alert and query it against threat intelligence platforms (like VirusTotal or AlienVault OTX) to identify the true malware family and obtain actionable context on its capabilities.</li>\n<li><strong>Enterprise-Wide Sweeps:</strong> Utilize the identified hash as an Indicator of Compromise (IOC) to sweep the entire enterprise network, ensuring the specific malicious file has not been dropped on other hosts.</li>\n</ul>",
  "cta": "Published by the SystemHelpdesk team.",
  "aliases": [
    "Trojan.Hash",
    "Malware.27d3e5bc",
    "Win32/27d3e5bc"
  ],
  "enrichment_level": "insufficient_information",
  "faq": [],
  "faq_count": 0,
  "mitre_attack": [],
  "cisa_advisory": null,
  "last_updated": "2026-07-01T16:40:53Z",
  "type": "Generic",
  "target_industries": [
    "Global / Opportunistic"
  ],
  "motivation": "Opportunistic",
  "threat_actors": [
    "Unknown / Cybercriminal"
  ],
  "target_geographies": [
    "Global"
  ]
}