27D3E5Bc

Category: ransomware · Aliases: Trojan.Hash, Malware.27d3e5bc, Win32/27d3e5bc · Sample count (EMBER 2018): 1 · Enrichment: insufficient_information · Updated: 2026-07-01T16:40:53Z

Category: RansomwareActor: Unknown / CybercriminalIndustry: Global / OpportunisticMotivation: Opportunistic

Overview

Executive Summary

"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.

Static Detection and Technical Context

Unlike 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. The implications of a hash-based detection include:

Absolute Confidence: Hash detections have a near-zero false-positive rate. If a file triggers this alert, it is definitively malicious (assuming no hash collisions).
Zero Behavioral Context: 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).
High Evasion Vulnerability: 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.

Threat Impact and Response

While 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).

Incident Mitigation Strategy

Verify Execution Status: 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.
Hash Enrichment Lookups: 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.
Enterprise-Wide Sweeps: 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.

Known aliases

Threat reports may refer to this family under multiple names:

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_27D3E5BC {
    meta:
        description = "Detects 27D3E5Bc (ransomware)"
        author = "SystemHelpdesk Boilerplate Generator"
        date = "2026-07-06"
    strings:
        $s1 = "27d3e5bc" ascii wide nocase
        $s2 = "trojan.hash" ascii wide nocase
        $s3 = "malware.27d3e5bc" ascii wide nocase
        $s4 = "win32/27d3e5bc" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

Sigma Rule

title: Suspicious 27D3E5Bc Activity
id: e313cd7b994f424906c220059e199fd4
status: experimental
description: Detects generic indicators of the 27d3e5bc malware family.
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains:
            - "*27d3e5bc*"
            - "*trojan.hash*"
            - "*malware.27d3e5bc*"
            - "*win32/27d3e5bc*"
    condition: selection
level: medium

References & External Analysis

Search "27d3e5bc" on VirusTotal (External Analysis)

Frequently Asked Questions

How do I remove the 27D3E5Bc Ransomware from Windows?

Manual removal of 27D3E5Bc 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 27D3E5Bc a virus or a Ransomware?

27D3E5Bc is classified as a Ransomware. Unlike traditional viruses that infect files, modern malware like 27D3E5Bc typically operates as a standalone payload designed to compromise systems, steal data, or deploy secondary stage implants.

What are the main symptoms of a 27D3E5Bc infection?

Symptoms of 27D3E5Bc 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: ransomware)

Explore other malware families in the same category:

Protect Your Network Against Ransomwares

Want to prevent 27D3E5Bc and similar threats from compromising your organization? Read our comprehensive defensive guide: Ransomware Protection Guide.

Need help with an active incident? Published by the SystemHelpdesk team.

Machine-readable

Get this profile as JSON: https://jordanricky1604-ship-it.github.io/malware-families-catalog/api/27d3e5bc.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.