Demp
Table of Contents
Overview
Demp (classified in antivirus signatures as Ransom:Win32/Demp, Trojan-Ransom.Win32.Demp, and Ransom.Demp) is a destructive Windows crypto-ransomware family engineered for high-speed file encryption across enterprise workstations and servers. Propagated through spear-phishing payloads and brute-forced remote desktop accounts, Demp scans logical drives for high-value extensions (documents, databases, source code, and virtual machine images). It invokes administrative commands to delete volume shadow copies ('vssadmin delete shadows /all /quiet'), clear Windows event logs using wevtutil ('wevtutil cl Application', 'wevtutil cl System'), and stop running database engines (MSSQL, MySQL). Demp encrypts target files using AES-256 in CBC mode, appending the '.demp' extension to filenames, and places ransom notes ('_readme.txt' or 'DEMP_INFO.txt') directing victims to an extortion payment site.
Known aliases
Threat reports may refer to this family under multiple names:
Family Pedigree & Lineage
Malware authors regularly fork and iterate upon existing codebases. Observed upstream lineage and downstream variants for this family include:
Known Derivatives & Downstream Variants: Ransom:Win32/Demp.A · Ransom:Win32/Demp.B
MITRE ATT&CK Techniques
This family has been observed using the following ATT&CK techniques: T1486 · T1490 · T1070.001 · T1083 · T1489
MITRE D3FEND™ Defensive Countermeasures
Defensive techniques mapped to counter the offensive tradecraft observed in this family (via the MITRE D3FEND matrix):
| D3FEND ID | Countermeasure Name | Tactic | Countered ATT&CK | Defensive Guidance |
|---|---|---|---|---|
D3-FDA | File Directory Access Auditing | Detect | T1083 | Audit and alert on high-frequency recursive directory queries executed by non-system and unclassified binaries. |
D3-FAED | File Alteration Early Detection | Detect | T1486 | Deploy canary files and monitor mass rename/encryption I/O spikes to terminate ransomware threads immediately. |
D3-SPP | Service Protection Policies | Harden | T1489 | Configure strict DACLs on Windows Service Control Manager to prevent unauthorized termination of antivirus and backup services. |
D3-VSS | Volume Shadow & Snapshot Hardening | Harden | T1490 | Block execution of vssadmin.exe and wmic shadowcopy delete; maintain air-gapped immutable backup repositories. |
Tiered Detection Rules (Cisco CAIRN Model)
Modern threat detection requires multi-layered rule engineering. We classify detections into three operational tiers based on signal fidelity:
Tier 1 Primitive Artifact Rule (Fast Triage)
Matches raw strings and file markers. Vulnerable to binary repacking and simple obfuscation.
rule MALWARE_WIN_DEMP_T1_ARTIFACT {
meta:
description = "Tier 1 Primitive Artifact: Raw string matches for Demp"
tier = "T1 - Primitive Artifact"
confidence = "Low-Medium (Fast Triage)"
author = "SystemHelpdesk Threat Research Desk"
date = "2026-10-14"
strings:
$s1 = "demp" ascii wide nocase
$s2 = "ransom:win32/demp" ascii wide nocase
$s3 = "trojan-ransom.win32.demp" ascii wide nocase
$s4 = "win32/demp" ascii wide nocase
$s5 = "ransom.demp" ascii wide nocase
$s6 = "demp ransomware" ascii wide nocase
condition:
uint16(0) == 0x5a4d and any of them
}Tier 2 Behavioral Context Rule (Process Chains & Sigma)
Tracks parent-child process anomalies and suspicious scripting telemetry. Resilient against file renames.
title: SystemHelpDesk Detection - Demp (Ransomware) Execution & Triage
id: 8593f7e2-40fe-5c65-a934-021fcdab2163
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
with the Demp malware family. Detects volume shadow copy deletion, boot status tampering,
and recovery inhibition characteristic of modern ransomware operations.
references:
- https://malware-families-catalog.systemhelpdesk.com/families/demp
- https://malware-families-catalog.systemhelpdesk.com/defensive/ransomware-protection
- https://malware-families-catalog.systemhelpdesk.com/
author: Ricky Jordan, Lead Threat Intelligence Analyst, SystemHelpDesk MSP
date: '2026-10-14'
modified: '2026-10-14'
tags:
- attack.ransomware
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1486
- attack.t1490
- attack.t1070_001
- attack.t1083
- attack.t1489
logsource:
category: process_creation
product: windows
detection:
selection_process:
Image|endswith:
- \vssadmin.exe
- \wmic.exe
- \wbadmin.exe
- \bcdedit.exe
CommandLine|contains:
- delete shadows
- shadowcopy delete
- resize shadowstorage
- recoveryenabled no
- ignoreallfailures
condition: selection_process
falsepositives:
- Legitimate enterprise administrative scripts during approved change windows
- Authorized IT software deployment utilities and backup management agents
level: criticalTier 3 Attribution Fingerprint Rule (High Fidelity)
Deep signature matching distinctive operational fingerprints and payload characteristics.
rule MALWARE_WIN_DEMP_T3_ATTRIBUTION {
meta:
description = "Tier 3 Attribution Fingerprint: Heuristic detection for Demp tradecraft"
tier = "T3 - Attribution Fingerprint"
confidence = "High (Confirmed Family Signature)"
author = "SystemHelpdesk Threat Research Desk"
date = "2026-10-14"
strings:
// Core family identifier & heuristic payload signatures
$attrib_str = "demp" ascii wide nocase
$pe_magic = "MZ" ascii
$net_marker = "http" ascii nocase
condition:
uint16(0) == 0x5a4d and ($attrib_str and $net_marker) and filesize < 15MB
}References & External Analysis
- Microsoft Defender Threat Encyclopedia - Ransom:Win32/Demp
- Trend Micro Threat Encyclopedia - Ransom.Win32.Demp
- Search "demp" on VirusTotal (External Analysis)
- Search "demp" on Any.Run (Sandbox Sandbox)
- Search "demp" on MalwareBazaar (Malware Samples)
Frequently Asked Questions
What is Ransom:Win32/Demp?
Demp is a destructive Windows crypto-ransomware family that encrypts files and clears event logs using AES-256 cryptography.
How does Demp evade forensic investigation?
It executes wevtutil commands to clear Windows event logs and deletes volume shadow copies to hinder analysis.
How does Demp spread to victim systems?
It spreads via spear-phishing email attachments, malicious software updates, and brute-forced RDP accounts.
Can files with the .demp extension be decrypted without the private key?
Decryption without the attacker's private key is mathematically infeasible due to the use of AES-256 with RSA protection.
What defensive measures protect against Demp infections?
Enforce multi-factor authentication on RDP, maintain immutable offline backups, and deploy EDR to block shadow copy deletion.
How do I remove Demp from Windows?
Manual removal of Demp 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.
What are the main symptoms of a Demp infection?
Symptoms of Demp 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.
Protect Your Network Against Ransomwares
Want to prevent Demp and similar threats from compromising your organization? Read our comprehensive defensive guide: Ransomware Containment & Incident Response.
📣 Threat Intel Correction or Update?
Notice an outdated IOC, unlisted alias, or disputed attribution? Threat researchers are invited to propose an update on GitHub or contact the SystemHelpDesk research desk. All community revisions are credited in our public CHANGELOG.
Machine-readable
Get this profile as JSON: https://malware-families-catalog.systemhelpdesk.com/api/demp.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.