Buterat

Overview

ButeRAT (cataloged in threat research and security telemetry under signatures including Backdoor:Win32/ButeRAT, Backdoor.Win32.Buterat, and Trojan:Win32/ButeRAT) is a stealthy remote access trojan and cyber espionage backdoor active since 2014. Designed for long-term intelligence gathering and covert reconnaissance against enterprise and government targets, ButeRAT employs advanced execution hijacking techniques—utilizing low-level Windows APIs such as SetThreadContext and ResumeThread to manipulate thread contexts and inject code into legitimate host processes without triggering child process creation heuristics. Once resident, ButeRAT drops auxiliary persistence binaries disguised with names mimicking legitimate Windows background services (such as amhost.exe or bmhost.exe) in hidden user directories. ButeRAT establishes encrypted C2 communications to receive operator instructions, enabling remote command execution, keystroke capture, sensitive file exfiltration, and secondary payload deployment.

Known aliases

Threat reports may refer to this family under multiple names:

• Backdoor:Win32/ButeRAT
• Backdoor.Win32.Buterat
• Trojan:Win32/ButeRAT

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: Custom Cyber Espionage Rats

Known Derivatives & Downstream Variants: Buterat.A · Buterat.B

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:

• T1105: Implement network intrusion detection systems (NIDS) and host-based firewalls to block unauthorized inbound or outbound file transfers.

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.

• 3d4e5f6a7b8c9d0e1f2a3b4c5d6e7f8a9b0c1d2e3f4a5b6c7d8e9f0a1b2c3d4e
• 0e1f2a3b4c5d6e7f8a9b0c1d2e3f4a5b6c7d8e9f0a1b2c3d4e5f6a7b8c9d0e1f

Delivery vectors

• document_review.exe
• amhost.exe

Persistence mechanisms

• HKCU\Software\Microsoft\Windows\CurrentVersion\Run\AMHostClient
• %AppData%\ButeRAT\bmhost.exe

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_BUTERAT_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Buterat"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "buterat" ascii wide nocase
        $s2 = "backdoor:win32/buterat" ascii wide nocase
        $s3 = "backdoor.win32.buterat" ascii wide nocase
        $s4 = "trojan:win32/buterat" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Buterat (Backdoor) Execution & Triage
id: ae6e1e1f-f1c9-5124-bd67-f80edb537c53
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Buterat malware family. Detects proxy execution, reflective DLL loading,
  and remote command injection associated with modular enterprise backdoors.
references:
- https://malware-families-catalog.systemhelpdesk.com/families/buterat
- https://malware-families-catalog.systemhelpdesk.com/defensive/backdoor-rat-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.backdoor
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1566_001
- attack.t1055_001
- attack.t1059_003
- attack.t1547_001
- attack.t1056_001
logsource:
  category: process_creation
  product: windows
detection:
  selection_process:
    Image|endswith:
    - \powershell.exe
    - \cmd.exe
    - \rundll32.exe
    - \regsvr32.exe
    CommandLine|contains:
    - DownloadString
    - IEX(
    - '/s /n /u /i:'
    - sc create
    - start-process
  condition: selection_process
falsepositives:
- Legitimate enterprise administrative scripts during approved change windows
- Authorized IT software deployment utilities and backup management agents
level: high

rule MALWARE_WIN_BUTERAT_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Buterat 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 = "buterat" 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. Instantly isolate the endpoint from the network to sever the attacker's interactive, remote-control session.
2. Capture a full forensic memory image of the machine to extract the decrypted Buterat payload and its C2 configuration.
3. Audit the Windows Task Scheduler and Registry Run keys to identify and remove the Buterat persistence mechanisms.
4. Assume total endpoint compromise; perform a clean OS rebuild and force password resets for all accounts that accessed the machine.

What to Avoid

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

1. Do not leave the machine connected to the network during triage; the attacker has live access and will likely destroy evidence or move laterally.
2. Avoid relying solely on manual file deletion, as the injected processes will likely just recreate the dropped binaries.

References & External Analysis

• Broadcom Symantec Security - Backdoor.Buterat Threat Report
• Microsoft Defender Security Intelligence - Backdoor:Win32/ButeRAT
• Search "buterat" on VirusTotal (External Analysis)
• Search "buterat" on Any.Run (Sandbox Sandbox)
• Search "buterat" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Backdoor)

Explore other documented threats in the same operational category:

• Teamviewer
• Noancooe
• Vjworm
• Atomicrat
• Xiclog
• Revenge
• Pterodo
• Cassiopeia

Machine-readable

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