Sign0Fmisery

Overview

Executive Summary

Infection Vector and Technical Capabilities

• Destructive Payload: Depending on the specific variant, the primary payload may involve mass file deletion, overwriting the Master Boot Record (MBR) to prevent the OS from booting, or forcefully terminating critical Windows services (like the Print Spooler or Windows Defender).
• System Instability: The malware often induces severe system instability, triggering Blue Screens of Death (BSODs) or freezing the user interface by launching infinite loops or consuming all available CPU and RAM resources.
• Backdoor Functionality: Some variants classified under this name also open undocumented network ports, establishing a rudimentary backdoor that allows the attacker to execute remote command-line instructions.

Threat Assessment

Incident Response and Remediation

• Emergency Network Isolation: Isolate the machine immediately to prevent the malware from attempting to spread laterally via open network shares or exploiting vulnerabilities on adjacent systems.
• System Triage and Data Recovery: Because the primary intent is often destructive, attempting to "clean" the OS is not recommended. The system should be booted from an offline rescue environment to assess data damage and attempt file recovery before a complete wipe.
• Complete Re-imaging: The only secure remediation is a bare-metal wipe and re-image from a trusted backup. Thoroughly investigate the initial infection vector to patch the vulnerability or address the social engineering tactic that allowed the execution.

Known aliases

Threat reports may refer to this family under multiple names:

• Trojan.Sign0fmisery
• HackTool.Sign0fmisery
• Win32/Sign0fmisery

MITRE ATT&CK Techniques

Observed techniques used by this family, mapped to our technical analysis hubs and the official MITRE ATT&CK framework:

MITRE D3FEND™ Defensive Countermeasures

Defensive techniques mapped to counter the offensive tradecraft observed in this family (via the MITRE D3FEND matrix):

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:

rule MALWARE_WIN_SIGN0FMISERY_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Sign0Fmisery"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "sign0fmisery" ascii wide nocase
        $s2 = "trojan.sign0fmisery" ascii wide nocase
        $s3 = "hacktool.sign0fmisery" ascii wide nocase
        $s4 = "win32/sign0fmisery" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Sign0fmisery (Trojan) Execution & Triage
id: 828a3235-b8cf-543d-b06b-dbd55310b7e6
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Sign0fmisery malware family. Detects suspicious execution from temporary
  user directories with hidden window flags and background transfer utilities.
references:
- https://malware-families-catalog.systemhelpdesk.com/families/sign0fmisery
- https://malware-families-catalog.systemhelpdesk.com/defensive/downloader-dropper-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.trojan
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1485
- attack.t1489
- attack.t1490
logsource:
  category: process_creation
  product: windows
detection:
  selection_process:
    Image|endswith:
    - \cmd.exe
    - \powershell.exe
    - \cscript.exe
    - \wscript.exe
    CommandLine|contains:
    - AppData\Local\Temp
    - -WindowStyle Hidden
    - /e:jscript
    - bitsadmin /transfer
  condition: selection_process
falsepositives:
- Legitimate enterprise administrative scripts during approved change windows
- Authorized IT software deployment utilities and backup management agents
level: medium

rule MALWARE_WIN_SIGN0FMISERY_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Sign0Fmisery 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 = "sign0fmisery" 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
}

Containment & Response Steps

Ordered checklist for responders. Adapt to your environment and engage professional support for active incidents.

1. Sever network connectivity for the flagged endpoint to terminate persistent command-and-control (C2) communication channels and stop Sign0Fmisery from retrieving secondary stage payloads.
2. Capture process memory triage to detect and terminate malicious threads injected by Sign0Fmisery into legitimate system processes such as explorer.exe or svchost.exe.
3. Audit Windows Registry Run keys (HKCU\Software\Microsoft\Windows\CurrentVersion\Run) and Task Scheduler entries to locate and purge Sign0Fmisery persistence hooks.
4. Deploy updated enterprise EDR detection signatures and conduct an out-of-band endpoint scan to isolate dropped binaries and staged payloads.
5. Rotate all credentials, domain user passwords, and session cookies active on the system during the Sign0Fmisery execution timeframe.

What to Avoid

Common mistakes during response to this family that can destroy evidence, spread the infection, or worsen recovery.

1. Do not assume the incident is resolved simply because an antivirus tool removed the initial Sign0Fmisery dropper; always verify that secondary payloads and persistence hooks have been eradicated.
2. Avoid logging in with Domain Admin or privileged credentials on a machine suspected of running Sign0Fmisery until memory triage is complete.
3. Do not delay host isolation; automated lateral movement and credential dumping can occur within minutes of initial execution.

References & External Analysis

• Search "sign0fmisery" on VirusTotal (External Analysis)
• Search "sign0fmisery" on Any.Run (Sandbox Sandbox)
• Search "sign0fmisery" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Trojan)

Explore other documented threats in the same operational category:

• Hvnc
• Fakeinstaller
• Schoolbus
• Vanbot
• Spesr
• Virtu
• Pjzab0Jsupjb
• Retefe

Machine-readable

Get this profile as JSON: https://malware-families-catalog.systemhelpdesk.com/api/sign0fmisery.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.