Fujacks
Table of Contents
Overview
Fujacks (cataloged across security vendors and threat intelligence databases under signatures including Virus:Win32/Fujacks, Worm.WhBoy, and famously known as the 'Panda Burning Joss Sticks' virus) is a legendary, highly destructive Windows PE file infector and worm created in 2006 by Chinese programmer Li Jun. Propagating aggressively across local drives, network SMB shares, and removable USB storage devices, Fujacks infects Windows executable (.exe, .scr, .pif) files by prepending its malicious viral code. Most notoriously, Fujacks modifies the resource sections of infected executables, replacing original application icons with a cartoon panda holding three burning sticks of incense (joss sticks). Fujacks terminates antivirus processes, deletes system ghost backups, steals gaming and messaging credentials, and downloads secondary malware from remote servers.
Known aliases
Threat reports may refer to this family under multiple names:
Family Pedigree & Lineage
Malware authors regularly fork and iterate upon existing codebases. Observed upstream lineage and downstream variants for this family include:
Known Derivatives & Downstream Variants: Virus:Win32/Fujacks.A · Worm.Whboy.2006
MITRE ATT&CK Techniques
This family has been observed using the following ATT&CK techniques: T1027 · T1091 · T1021.002 · T1562.001 · T1547.001 · T1105 · T1082
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):
| D3FEND ID | Countermeasure Name | Tactic | Countered ATT&CK | Defensive Guidance |
|---|---|---|---|---|
D3-NBA | Network Behavioral Analysis | Detect | T1021.002 | Enforce SMB message signing, disable legacy SMBv1, and restrict administrative share access (C$, ADMIN$) to dedicated PAM bastion hosts. |
D3-BDA | Binary De-obfuscation & Unpacking | Analyze | T1027 | Utilize memory dump scanners and entropy inspection to unpack encrypted stagers during process creation. |
D3-SDA | System Discovery Analysis | Detect | T1082 | Alert on rapid enumerations of systeminfo, hostname, and registry hardware trees in short intervals. |
D3-RMC | Removable Media Access Control | Harden | T1091 | Enforce Group Policy settings disabling Windows autorun and block execution permissions on removable USB storage media. |
D3-NTI | Network Traffic Inspection | Detect | T1105 | Inspect deep packet payloads for anomalous staging binaries and unauthorized egress protocols. |
D3-RPM | Registry Persistence Monitoring | Detect | T1547.001 | Audit and restrict write privileges to user and machine-level Registry Run/RunOnce keys using Endpoint Privilege Management. |
D3-STA | Security Tool Anti-Tamper Enforcement | Harden | T1562.001 | Block unauthorized modification of antivirus registry flags and prevent stopping security agent services. |
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_FUJACKS_T1_ARTIFACT {
meta:
description = "Tier 1 Primitive Artifact: Raw string matches for Fujacks"
tier = "T1 - Primitive Artifact"
confidence = "Low-Medium (Fast Triage)"
author = "SystemHelpdesk Threat Research Desk"
date = "2026-10-14"
strings:
$s1 = "fujacks" ascii wide nocase
$s2 = "virus:win32/fujacks" ascii wide nocase
$s3 = "worm.whboy" ascii wide nocase
$s4 = "panda burning joss sticks" ascii wide nocase
$s5 = "w32/fujacks" ascii wide nocase
$s6 = "virus.win32.fujacks" 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 - Fujacks (File Infector) Execution & Triage
id: f267e8f9-72fa-5916-b1ed-2a713d108d0c
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
with the Fujacks 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/fujacks
- 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.file-infector
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1027
- attack.t1091
- attack.t1021_002
- attack.t1562_001
- attack.t1547_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: mediumTier 3 Attribution Fingerprint Rule (High Fidelity)
Deep signature matching distinctive operational fingerprints and payload characteristics.
rule MALWARE_WIN_FUJACKS_T3_ATTRIBUTION {
meta:
description = "Tier 3 Attribution Fingerprint: Heuristic detection for Fujacks 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 = "fujacks" 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
}References & External Analysis
- Microsoft Defender Threat Encyclopedia - Virus:Win32/Fujacks
- Search "fujacks" on VirusTotal (External Analysis)
- Search "fujacks" on Any.Run (Sandbox Sandbox)
- Search "fujacks" on MalwareBazaar (Malware Samples)
Frequently Asked Questions
What is Virus:Win32/Fujacks (Panda Burning Incense)?
Fujacks is a legendary Windows file-infecting worm that replaces executable icons with a panda holding burning joss sticks.
Who created the Fujacks virus and when?
It was created in late 2006 by Chinese programmer Li Jun, who was later arrested and sentenced by authorities in 2007.
How does Fujacks infect executable files on Windows?
It prepends its viral code to .exe, .scr, and .pif files and overwrites their embedded icon resources with the panda graphic.
How did Fujacks spread across enterprise networks?
It spread via writable SMB network shares, infected USB flash drives with autorun.inf files, and compromised web downloads.
How can systems infected with Fujacks be disinfected?
Boot from clean rescue media, run dedicated antivirus disinfection tools to extract viral prepends, and repair core Windows binaries.
How do I remove Fujacks from Windows?
Manual removal of Fujacks 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.
What are the main symptoms of a Fujacks infection?
Symptoms of Fujacks 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 File_Infectors
Want to prevent Fujacks and similar threats from compromising your organization? Read our comprehensive defensive guide: Think You've Been Hacked? What To Do First.
📣 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/fujacks.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.