Omyaamfbexii
Table of Contents
Overview
Executive Summary
"Omyaamfbexii" is a generic detection identifier rather than a distinct, named malware family. It is typically generated automatically by antivirus engines—often via machine learning or heuristic analysis—to flag highly obfuscated executables or domains generated by a Domain Generation Algorithm (DGA) that exhibit malicious characteristics.Behavioral Analysis and Heuristic Triggers
The seemingly random string "omyaamfbexii" is characteristic of automated naming conventions used by security vendors when a file matches a behavioral profile of a trojan, but lacks a specific signature tying it to a known family (like Emotet or Trickbot). Files flagged with this identifier frequently exhibit the following behaviors during dynamic analysis (sandboxing):- Heavy Obfuscation: The executable is often packed using custom or commercial packers (e.g., UPX, Themida) to thwart static analysis and reverse engineering.
- DGA Communications: The malware may attempt to resolve domain names consisting of pseudo-random character strings, indicating the use of a Domain Generation Algorithm to locate its command-and-control (C2) server.
- Process Injection: It frequently attempts to inject malicious code into legitimate system processes (`explorer.exe`, `svchost.exe`) to hide its execution and bypass local firewalls.
Security Implications
While a generic detection might seem less threatening than a named APT group, it often indicates the presence of a novel, zero-day threat, or a heavily mutated variant of existing malware. These files are typically downloaders or initial access trojans designed to pave the way for ransomware deployments.Investigation and Remediation
- File Isolation and Analysis: Immediately isolate the endpoint where the file was detected. Submit the flagged executable to an advanced malware sandbox or a malware analysis team to determine its true capabilities.
- Network Forensics: Analyze network logs for DNS queries matching random strings, which may indicate successful DGA communication and provide IOCs (Indicators of Compromise) for blocking.
- Comprehensive Sweeps: Utilize the IOCs gathered from dynamic analysis to sweep the entire enterprise network for lateral movement or secondary infections.
Known aliases
Threat reports may refer to this family under multiple names:
MITRE ATT&CK Techniques
Observed techniques used by this family, mapped to our technical analysis hubs and the official MITRE ATT&CK framework:
| Technique | Name | Tactic | Official Spec |
|---|---|---|---|
T1059 | Command and Scripting Interpreter | Execution | ATT&CK ↗ |
T1568.002 | Dynamic Resolution: Domain Generation Algorithms (DGA) (Evading C2 blacklisting) | Command and Control | ATT&CK ↗ |
T1027 | Obfuscated Files or Information | Defense Evasion | ATT&CK ↗ |
Tactical Mitigations
Based on the techniques used by this family, consider the following defensive strategies:
- T1059: Restrict execution of scripting languages such as PowerShell, VBScript, or Python to authorized administrators. Enforce Script Block Logging.
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-BDA | Binary De-obfuscation & Unpacking | Analyze | T1027 | Utilize memory dump scanners and entropy inspection to unpack encrypted stagers during process creation. |
D3-SEA | Script Execution Analysis | Detect | T1059 | Analyze script block syntax and command arguments at runtime to detect malicious automation. |
D3-DNSR | DNS Reputation Analysis | Detect | T1568.002 | Deploy recursive DNS security resolvers with algorithmic domain scoring (entropy and n-gram models) to automatically sinkhole DGA queries. |
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_OMYAAMFBEXII_T1_ARTIFACT {
meta:
description = "Tier 1 Primitive Artifact: Raw string matches for Omyaamfbexii"
tier = "T1 - Primitive Artifact"
confidence = "Low-Medium (Fast Triage)"
author = "SystemHelpdesk Threat Research Desk"
date = "2026-10-14"
strings:
$s1 = "omyaamfbexii" ascii wide nocase
$s2 = "generic.omyaamfbexii" ascii wide nocase
$s3 = "trojan.generic" ascii wide nocase
$s4 = "dga.generic" 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 - Omyaamfbexii (Ransomware) Execution & Triage
id: 2a15bf75-69f0-58ff-9961-91fce72ae161
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
with the Omyaamfbexii 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/omyaamfbexii
- 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.t1059
- attack.t1568_002
- attack.t1027
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_OMYAAMFBEXII_T3_ATTRIBUTION {
meta:
description = "Tier 3 Attribution Fingerprint: Heuristic detection for Omyaamfbexii 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 = "omyaamfbexii" 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.
- Immediately isolate affected host(s) from the internal network (disconnect physical Ethernet and disable Wi-Fi/Bluetooth) to prevent Omyaamfbexii from spreading laterally or encrypting network-attached storage (NAS) and shared SMB volumes.
- Preserve volatile system memory (RAM capture) on a representative endpoint before attempting a reboot or power-down, as Omyaamfbexii symmetric encryption keys or uncompiled payload components may still reside in memory.
- Audit process execution logs and terminate active scripting interpreters (e.g. PowerShell, CMD, WScript) or commands executing 'vssadmin.exe delete shadows' or 'wbadmin' used by Omyaamfbexii to inhibit recovery.
- Investigate the initial compromise vector (such as exposed RDP instances, spearphishing attachments, or vulnerable edge gateways) and enforce an immediate credential reset for all compromised Active Directory accounts.
- Restore critical assets and databases exclusively from verified, air-gapped, or immutable offline backups once the Omyaamfbexii binary and related persistence hooks are eradicated.
What to Avoid
Common mistakes during response to this family that can destroy evidence, spread the infection, or worsen recovery.
- Do not restart or power cycle infected systems prematurely; doing so destroys volatile RAM encryption keys and may trigger bootloader locking logic embedded in Omyaamfbexii.
- Avoid negotiating or paying the extortion demand without prior forensic evaluation and consultation with incident response specialists, as payment does not guarantee data recovery.
- Do not connect clean backup drives or external storage to the affected network until Omyaamfbexii eradication is completely verified.
References & External Analysis
- Search "omyaamfbexii" on VirusTotal (External Analysis)
- Search "omyaamfbexii" on Any.Run (Sandbox Sandbox)
- Search "omyaamfbexii" on MalwareBazaar (Malware Samples)
Frequently Asked Questions
What is Omyaamfbexii and what threat category does it belong to?
Omyaamfbexii is classified as a Ransomware. Documented across security telemetry, it is engineered to execute unauthorized operations, establish persistent footholds on target endpoints, and facilitate malicious campaigns targeting enterprise and individual environments.
How does Omyaamfbexii establish persistence and evade defensive controls?
Omyaamfbexii typically establishes persistence through registry run keys, scheduled tasks, or service installations, while evading signature-based antivirus solutions through code obfuscation, memory injection, or anti-analysis sandbox checks.
What are the essential incident response steps for mitigating a Omyaamfbexii compromise?
Security teams responding to Omyaamfbexii should immediately isolate affected endpoints from the network, perform memory triage to capture volatile forensic artifacts, audit registry and startup persistence mechanisms, revoke exposed user credentials, and restore systems from verified, clean backups.
What cryptographic algorithms and file targeting techniques does Generic.Omyaamfbexii employ during execution?
Generic.Omyaamfbexii typically leverages hybrid cryptographic architectures combining symmetric stream or block ciphers (such as AES-256 or ChaCha20) for rapid file encryption with asymmetric algorithms (such as RSA-2048 or Curve25519) to securely protect the session keys. It aggressively targets sensitive file extensions including corporate documents, databases, virtual disks, and backups while systematically executing commands to delete Volume Shadow Copies (vssadmin delete shadows /all /quiet) and disable system recovery options.
Are decryptors available for Generic.Omyaamfbexii, and what is the recommended recovery procedure?
Decryption availability for Generic.Omyaamfbexii depends on whether security researchers or law enforcement (such as the No More Ransom initiative) have recovered the master private keys or discovered flaws in its key generation routines. Victims should never pay the extortion demand, as payment fuels criminal operations without guaranteeing file restoration. The recommended recovery procedure entails isolating infected hosts, conducting forensic disk imaging, identifying the root access vector, and restoring validated systems from immutable offline backups.
How do I remove the Omyaamfbexii Ransomware from Windows?
Manual removal of Omyaamfbexii 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 Omyaamfbexii a virus or a Ransomware?
Omyaamfbexii is classified as a Ransomware. Unlike traditional viruses that infect files, modern malware like Omyaamfbexii typically operates as a standalone payload designed to compromise systems, steal data, or deploy secondary stage implants.
What are the main symptoms of a Omyaamfbexii infection?
Symptoms of Omyaamfbexii 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 Omyaamfbexii 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/omyaamfbexii.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.