Fakeff

Overview

Executive Summary

Infection Vector and Technical Capabilities

• Deceptive Installation: The malware installer meticulously copies the icons, branding, and user interface of legitimate Mozilla Firefox software to lull the user into a false sense of security while they click "Next" through the wizard.
• Browser Hijacking: The malware often installs a malicious Browser Helper Object (BHO) or extension into the real browser, or it may entirely replace the Firefox shortcut on the desktop to point to a modified, attacker-controlled executable.
• Traffic Manipulation: Once integrated, FakeFF intercepts web traffic, forcefully redirecting the user's search queries to dubious affiliate marketing portals, injecting pop-up advertisements into legitimate sites, and silently tracking the user's browsing history.

Threat Assessment

Incident Response and Remediation

• Application Removal: The primary remediation step is to locate and uninstall the fake application. Check the Windows Control Panel for recently installed programs claiming to be "Firefox Updates" or bearing suspicious publisher names.
• Shortcut Verification: Right-click the browser shortcuts on the Desktop and Taskbar. Verify that the "Target" field points to the legitimate executable (e.g., `C:\Program Files\Mozilla Firefox\firefox.exe`) and not a malicious script or proxy application.
• Browser Reset and Sweeps: Perform a complete factory reset of the legitimate web browser to clear any malicious extensions. Run a comprehensive scan with a reputable enterprise anti-malware solution to remove lingering adware components.

Known aliases

Threat reports may refer to this family under multiple names:

• Adware.FakeFF
• PUP.FakeFirefox
• Trojan.FakeBrowser

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:

• T1036.005: Monitor for executable files running from unusual paths or with deceptive names. Use EDR to detect process masquerading.
• T1185: Enforce strong MFA and use browser isolation or hardened browsers for sensitive financial or administrative portals to defeat session hijacking.

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_FAKEFF_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Fakeff"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "fakeff" ascii wide nocase
        $s2 = "adware.fakeff" ascii wide nocase
        $s3 = "pup.fakefirefox" ascii wide nocase
        $s4 = "trojan.fakebrowser" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Fakeff (Trojan) Execution & Triage
id: aaed2ee2-c3b7-5305-a4a6-6969268c1219
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Fakeff 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/fakeff
- 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.t1036_005
- attack.t1185
- attack.t1176
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_FAKEFF_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Fakeff 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 = "fakeff" 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. Sever network connectivity for the flagged endpoint to terminate persistent command-and-control (C2) communication channels and stop Fakeff from retrieving secondary stage payloads.
2. Capture process memory triage to detect and terminate malicious threads injected by Fakeff into legitimate system processes such as explorer.exe or svchost.exe.
3. Audit Windows Registry Run keys (HKCU\Software\Microsoft\Windows\CurrentVersion\Run) and Task Scheduler entries to locate and purge Fakeff persistence hooks.
4. Deploy updated enterprise EDR detection signatures and conduct an out-of-band endpoint scan to isolate dropped binaries and staged payloads.
5. Rotate all credentials, domain user passwords, and session cookies active on the system during the Fakeff execution timeframe.

What to Avoid

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

1. Do not assume the incident is resolved simply because an antivirus tool removed the initial Fakeff dropper; always verify that secondary payloads and persistence hooks have been eradicated.
2. Avoid logging in with Domain Admin or privileged credentials on a machine suspected of running Fakeff until memory triage is complete.
3. Do not delay host isolation; automated lateral movement and credential dumping can occur within minutes of initial execution.

References & External Analysis

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

Frequently Asked Questions

Related Threats (Category: Trojan)

Explore other documented threats in the same operational category:

• Kura
• Cleanlog
• Favadd
• Zurgop
• Metel
• Hack_A_Tack
• Hotkeyshook
• Premium

Machine-readable

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