Guagua

Overview

Guagua (classified in antimalware telemetry under signatures including Trojan:Win32/Guagua, Trojan:Win32/Guagua.A, and Backdoor:Win32/Guagua) is a modular Windows remote access trojan and backdoor. Infiltrating victim environments through malicious drive-by downloads, phishing lures, and software cracking utilities, Guagua implements defensive evasion mechanisms including API hooking detection and virtual sandbox bypasses. It establishes autostart persistence by creating registry entries under HKCU\Software\Microsoft\Windows\CurrentVersion\Run or registering background service components. Guagua connects to remote command-and-control servers via TCP sockets or HTTP sessions, allowing remote operators to perform keystroke logging, capture screen snapshots, execute command-line instructions, harvest stored credentials, and download secondary malware modules.

Known aliases

Threat reports may refer to this family under multiple names:

• Trojan:Win32/Guagua
• Trojan:Win32/Guagua.A
• Backdoor:Win32/Guagua
• Win32/Guagua
• Backdoor.Guagua

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:

• T1056.001: Implement Endpoint Detection and Response (EDR) to monitor for suspicious API calls related to keystroke interception. Enforce Multi-Factor Authentication (MFA) to render stolen passwords useless.
• T1059.003: Restrict execution of Windows Command Shell (cmd.exe) and block unauthorized batch scripts.
• T1071.001: Implement web filtering and SSL/TLS inspection to detect malicious command and control (C2) traffic hiding in HTTP/HTTPS.
• T1113: Monitor for frequent or unauthorized screen captures or clipboard reads. Restrict background applications from accessing desktop APIs.

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_GUAGUA_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Guagua"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "guagua" ascii wide nocase
        $s2 = "trojan:win32/guagua" ascii wide nocase
        $s3 = "trojan:win32/guagua.a" ascii wide nocase
        $s4 = "backdoor:win32/guagua" ascii wide nocase
        $s5 = "win32/guagua" ascii wide nocase
        $s6 = "backdoor.guagua" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Guagua (Trojan) Execution & Triage
id: ce9fa3ca-08f1-5aeb-870d-df7b04e812d0
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Guagua 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/guagua
- 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.t1059_003
- attack.t1056_001
- attack.t1113
- attack.t1547_001
- attack.t1071_001
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_GUAGUA_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Guagua 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 = "guagua" 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. Disconnect the affected host from network segments immediately to terminate active C2 control sessions.
2. Kill unauthorized processes executing from %APPDATA% or %TEMP% directories.
3. Inspect and delete startup values under HKCU\Software\Microsoft\Windows\CurrentVersion\Run.
4. Block outbound C2 IP addresses and domains across perimeter firewalls and web proxies.
5. Audit access logs for signs of lateral movement and force reset passwords for accounts logged in during the compromise.

What to Avoid

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

1. Do not allow the infected host to communicate outbound while conducting forensic analysis.
2. Do not assume removing the trojan binary revokes credentials that may have already been exfiltrated.

References & External Analysis

• Microsoft Defender Threat Encyclopedia - Trojan:Win32/Guagua
• Trend Micro Threat Encyclopedia - Backdoor.Win32.Guagua
• VirusTotal Threat Intelligence
• Search "guagua" on VirusTotal (External Analysis)
• Search "guagua" on Any.Run (Sandbox Sandbox)
• Search "guagua" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Trojan)

Explore other documented threats in the same operational category:

• Uk_Splitter
• Erazer
• Netdevil
• Hmgfa45Id4O
• Bayrob
• Gamaredon
• Scarcruft
• Zpevdo

Machine-readable

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