Retefe

Overview

Retefe (historically documented as Trojan:Win32/Retefe and Trojan-Banker.Win32.Retefe) is a sophisticated banking trojan that actively targeted banking institutions across Switzerland, Austria, Sweden, and Japan from 2013 to 2019. Distributed via spear-phishing emails with malicious .zip or .js attachments, Retefe modifies system proxy settings and installs a rogue Certificate Authority (CA) root certificate directly into the Windows Certificate Store. It routes web traffic destined for targeted online banking domains through the Tor anonymity network or attacker-controlled proxy servers. This man-in-the-middle architecture allows Retefe to inject malicious web forms, harvest banking credentials, and intercept two-factor authentication tokens seamlessly without raising browser SSL/TLS certificate warnings.

Known aliases

Threat reports may refer to this family under multiple names:

• Trojan:Win32/Retefe
• Trojan-Banker.Win32.Retefe
• Win32/Retefe
• Retefe Banking Trojan
• Retefe Proxy Trojan

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:

• T1059.001: Restrict execution of PowerShell. Enforce PowerShell Constrained Language Mode and Script Block Logging.
• 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_RETEFE_T1_ARTIFACT {
    meta:
        description = "Tier 1 Primitive Artifact: Raw string matches for Retefe"
        tier = "T1 - Primitive Artifact"
        confidence = "Low-Medium (Fast Triage)"
        author = "SystemHelpdesk Threat Research Desk"
        date = "2026-10-14"
    strings:
        $s1 = "retefe" ascii wide nocase
        $s2 = "trojan:win32/retefe" ascii wide nocase
        $s3 = "trojan-banker.win32.retefe" ascii wide nocase
        $s4 = "win32/retefe" ascii wide nocase
        $s5 = "retefe banking trojan" ascii wide nocase
        $s6 = "retefe proxy trojan" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

title: SystemHelpDesk Detection - Retefe (Trojan) Execution & Triage
id: 7f9887cd-e222-55e7-a4df-d986d1229112
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
  with the Retefe 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/retefe
- 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.t1553_004
- attack.t1112
- attack.t1071_001
- attack.t1566_001
- attack.t1059_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_RETEFE_T3_ATTRIBUTION {
    meta:
        description = "Tier 3 Attribution Fingerprint: Heuristic detection for Retefe 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 = "retefe" 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 the endpoint; the attacker is actively performing Man-in-the-Middle attacks on the user's web traffic.
2. Remove the malicious Proxy Auto-Configuration (PAC) script from Windows Internet Options and Registry (`HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings`).
3. Audit the Windows Certificate Store (certmgr.msc) and remove any unauthorized Root CA certificates installed by the malware.
4. Enforce immediate enterprise-wide password resets for the affected user, assuming all typed credentials have been compromised.

What to Avoid

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

1. Do not assume changing passwords is sufficient; if the rogue Root CA and malicious PAC file are not removed, the attacker will immediately steal the new passwords.
2. Avoid relying solely on file-based antivirus, as Retefe's core logic often relies on native Windows scripting (PowerShell) and configuration changes.

References & External Analysis

• Trend Micro Security Research - Retefe Banking Trojan Technical Breakdown
• Microsoft Defender Threat Encyclopedia - Trojan:Win32/Retefe
• MITRE ATT&CK - Subvert Trust Controls: Install Root Certificate (T1553.004)
• Search "retefe" on VirusTotal (External Analysis)
• Search "retefe" on Any.Run (Sandbox Sandbox)
• Search "retefe" on MalwareBazaar (Malware Samples)

Frequently Asked Questions

Related Threats (Category: Trojan)

Explore other documented threats in the same operational category:

• Shelma
• Delf
• Polypatch
• Xxybyu
• Zepfod
• Siscos
• Bozok
• Mozla

Machine-readable

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