Zs0Bbeypkrh

Overview

Trojan:Win32/Zs0bbeypkrh (or similar auto-generated strings) represents the antivirus industry's response to highly polymorphic malware or Domain Generation Algorithms (DGA). Instead of a named family, this string is a generic, randomized identifier assigned by an AV engine to a threat that is rapidly shifting its signature to evade detection (`T1027`). This indicates the presence of a sophisticated dropper or a botnet agent actively communicating with shifting C2 infrastructure.

Understanding Polymorphic/DGA Identifiers
To an end-user, the file is simply blocked. For a SOC analyst, a detection with a randomized name like 'Zs0bbeypkrh' is a signal that static IOCs (like file hashes) will be nearly useless for hunting. The attacker is using automated tools to recompile the malware for every victim, or using DGA to contact thousands of different domains a day.

Execution and Polymorphic Mechanics
When executed, polymorphic threats unpack themselves dynamically in memory (`T1027.002`). They often inject their code into legitimate processes (like `svchost.exe`) (`T1055`) to hide their activity. If the threat utilizes DGA (`T1568.002`), it uses a mathematical algorithm to generate hundreds of potential C2 domain names (e.g., `ajkf83nd.com`, `93kmdla.net`). The malware attempts to connect to these domains until it finds one that the attacker has actually registered and activated for that day's operations, making IP/Domain blacklisting highly ineffective.

Indicators of Compromise & Impact
The impact depends entirely on the payload the polymorphic dropper intends to deliver (ransomware, infostealers, etc.). Host-based IoCs must focus on behavior: EDR alerts for process injection, anomalous child process spawning, or rapid creation/deletion of temporary files. Network IoCs are characterized by the malware generating a massive volume of DNS requests for non-existent, randomly generated domains (NXDOMAIN responses), mixed with a few successful connections.

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_ZS0BBEYPKRH_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Zs0Bbeypkrh"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "zs0bbeypkrh" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Zs0bbeypkrh (Ransomware) Execution & Triage
id: 30cd2cc3-87aa-5785-80aa-66a7c06512c8
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Zs0bbeypkrh 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/zs0bbeypkrh
- 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.t1055
- attack.t1027
- attack.t1568_002
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: critical

rule MALWARE_WIN_ZS0BBEYPKRH_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Zs0Bbeypkrh 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 = "zs0bbeypkrh" 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. Isolate the endpoint immediately; polymorphic droppers are typically the first stage of a much larger attack sequence.
2. Rely on EDR behavioral rules (e.g., blocking suspicious process injections) rather than relying on the AV signature that caught this specific variant.
3. Analyze DNS logs for the infected host to identify the algorithm used by the DGA, and block the successful connections.
4. Submit the memory dump or the quarantined file to a dynamic sandbox to identify the *actual* payload it was attempting to deploy.

What to Avoid

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

1. Do not waste time searching the enterprise for the specific file hash associated with 'Zs0bbeypkrh'; it is likely unique to that single machine.
2. Avoid trying to manually block every domain generated by a DGA; the attacker can generate them faster than you can block them.

References & External Analysis

• Search "zs0bbeypkrh" on VirusTotal (External Analysis)
• Search "zs0bbeypkrh" on Any.Run (Sandbox Sandbox)
• Search "zs0bbeypkrh" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Ransomware)

Explore other documented threats in the same operational category:

• Quant
• Vbcode
• Utoti
• Tnega
• Sinresby
• Zbiw
• Genericrxew
• Vbmod

Machine-readable

Get this profile as JSON: https://malware-families-catalog.systemhelpdesk.com/api/zs0bbeypkrh.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.