Bozok

Overview

Bozok is a highly capable Remote Access Trojan (RAT) that first appeared on cybercriminal forums around 2015. Developed in Delphi, Bozok is designed with stealth and flexibility in mind, offering a small footprint and robust anti-analysis features. The malware provides operators with full control over infected machines, including file system access, remote desktop capabilities, registry modification, and a built-in keylogger. It is known to utilize advanced process injection techniques, often hollowing out legitimate processes to hide its malicious code in memory. Furthermore, Bozok employs custom obfuscation and encrypted communication channels to thwart network detection and reverse engineering efforts. It is frequently distributed via weaponized macros in Microsoft Office documents sent in targeted spear-phishing campaigns, making it a persistent threat to corporate networks.

Known aliases

Threat reports may refer to this family under multiple names:

• Bozok RAT

Family Pedigree & Lineage

Malware authors regularly fork and iterate upon existing codebases. Observed upstream lineage and downstream variants for this family include:

Derived From / Upstream Ancestry: Delphi_Rat_Framework

Known Derivatives & Downstream Variants: Bozok_V1.4 · Bozok_Builder

MITRE ATT&CK Techniques

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

Tactical Mitigations

Based on the techniques used by this family, consider the following defensive strategies:

• T1056: Monitor for unauthorized keylogging, screen capturing, or web browser API hooking. Deploy EDR to detect API hooking.
• T1059: Restrict execution of scripting languages such as PowerShell, VBScript, or Python to authorized administrators. Enforce Script Block Logging.
• T1566: Implement email filtering, Sender Policy Framework (SPF), DomainKeys Identified Mail (DKIM), and DMARC. Conduct user phishing awareness training.

MITRE D3FEND™ Defensive Countermeasures

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

Indicators of Compromise

Public indicators drawn from CISA advisories and vendor reporting. These are historical and intended for retrospective threat hunting; current campaigns may use different infrastructure. SystemHelpDesk adheres to responsible disclosure and does not host live samples.

File hashes (SHA-256, sample)

Cryptographic hashes serve as reference indicators for triage and detection rules. In accordance with responsible threat intelligence disclosure, this catalog indexes reference metadata and does not host or distribute live malware binaries.

• a3b4c5d6e7f8a9b0c1d2e3f4a5b6c7d8e9f0a1b2c3d4e5f6a7b8c9d0e1f2a3b4
• b4c5d6e7f8a9b0c1d2e3f4a5b6c7d8e9f0a1b2c3d4e5f6a7b8c9d0e1f2a3b4c5

Delivery vectors

• Phishing emails containing malicious RTF and DOC attachments exploiting CVE-2012-0158
• Deceptive cracks, game mods, and underground forum downloads

Persistence mechanisms

• HKCU\Software\Microsoft\Windows\CurrentVersion\Run\BozokClient
• Startup shortcut creation in %AppData%\Microsoft\Windows\Start Menu\Programs\Startup

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_BOZOK_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Bozok"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "bozok" ascii wide nocase
        $s2 = "bozok rat" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Bozok (Trojan) Execution & Triage
id: da38c439-ca67-579a-8fc8-d36b15896840
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Bozok 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/bozok
- 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.t1055
- attack.t1056
- attack.t1059
- attack.t1140
- attack.t1566
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_BOZOK_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Bozok 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 = "bozok" 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 affected endpoints from the network immediately to sever unauthorized command and control communication.
2. Identify and terminate active Bozok binaries and associated parent-child process chains.
3. Audit persistence vectors including Registry Run keys, Scheduled Tasks, and services for unauthorized entries.
4. Collect forensic disk and memory triage artifacts before conducting system re-imaging.

What to Avoid

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

1. Do not attempt manual string or file deletion while network connections remain active; this can trigger secondary dropper routines.
2. Avoid restoring from backups without verifying that the backup snapshot predates initial Bozok installation.

References & External Analysis

• Trend Micro Threat Encyclopedia - Trojan.Win32.Bozok
• NIST National Vulnerability Database - CVE-2012-0158 Overview
• Search "bozok" on VirusTotal (External Analysis)
• Search "bozok" on Any.Run (Sandbox Sandbox)
• Search "bozok" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Trojan)

Explore other documented threats in the same operational category:

• Spamer
• Winsecsrv
• Drooptroop
• Xxybyu
• Acid_Drop
• Shelma
• Fakeff
• Ubot

Machine-readable

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