Multibanker

Overview

Trojan:Win32/Multibanker represents a sophisticated class of financial malware designed to target multiple banking institutions simultaneously. Unlike older, single-target trojans, Multibanker utilizes dynamic configuration files pulled from a Command-and-Control (C2) server, allowing it to adapt its web injects and credential-stealing routines to intercept login attempts across dozens of different online banking portals (`T1185`).

Understanding Multibanker (Financial Fraud)
To an end-user, the infection is entirely invisible. They will navigate to their legitimate bank website, log in as usual, but the trojan silently intercepts and modifies the transaction in the background. For financial institutions, Multibanker represents a severe threat, as it frequently bypasses standard Two-Factor Authentication (2FA) by tricking the user into entering their OTP into a fake web form injected by the malware.

Execution and Web Injection Mechanics
Multibanker is typically distributed via malspam (weaponized Office documents) or exploit kits. Upon execution, it establishes persistence (often via Registry Run keys) and injects itself into browser processes (`chrome.exe`, `firefox.exe`, `iexplore.exe`) (`T1055`). It then intercepts API calls related to network traffic (like `HttpSendRequest`). When the user navigates to a targeted bank, Multibanker uses 'Web Injects' (`T1185`) to alter the HTML of the webpage in real-time, inserting extra fields asking for credit card numbers, ATM PINs, or OTPs, which are immediately exfiltrated to the attacker (`T1041`).

Indicators of Compromise & Impact
The impact is direct financial fraud and total credential compromise. Host-based IoCs include EDR alerts for process injection (specifically into browser processes), unexpected network connections from legitimate browsers to unknown IP addresses (the C2 server fetching the inject configurations), and the presence of hidden, encrypted configuration files in `%AppData%`. Network IoCs involve the browser making encrypted POST requests to the C2 server containing the stolen credentials.

MITRE ATT&CK Techniques

Observed techniques used by this family, mapped to the MITRE ATT&CK framework:

Tactical Mitigations

Based on the techniques used by this family, consider the following defensive strategies:

• T1185: Enforce strong MFA and use browser isolation or hardened browsers for sensitive financial or administrative portals to defeat session hijacking.

Generated Detections (Boilerplate)

These YARA and Sigma rules are auto-generated based on the family name and aliases. They must be heavily tuned before deployment in a production environment.

YARA Rule

rule MALWARE_WIN_MULTIBANKER {
    meta:
        description = "Detects Multibanker (trojan)"
        author = "SystemHelpdesk Boilerplate Generator"
        date = "2026-07-06"
    strings:
        $s1 = "multibanker" ascii wide nocase
    condition:
        uint16(0) == 0x5a4d and any of them
}

Sigma Rule

title: Suspicious Multibanker Activity
id: f1b5a3cfc9ad1bb1fb47fef3011d7212
status: experimental
description: Detects generic indicators of the multibanker malware family.
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains:
            - "*multibanker*"
    condition: selection
level: medium

Containment & Response Steps

Ordered checklist for responders. Adapt to your environment and engage professional support for active incidents.

1. Isolate the endpoint immediately to prevent further credential exfiltration and unauthorized transactions.
2. Assume all credentials stored in or used via web browsers on the infected machine have been compromised.
3. Contact financial institutions immediately to freeze accounts, report the compromise, and monitor for fraudulent transactions.
4. Capture a memory dump before remediation to extract the active web inject configurations and identify the targeted banks.

What to Avoid

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

1. Do not assume that changing the password will stop the fraud; if the malware is still active, it will simply steal the new password and any new OTPs.
2. Avoid logging into any secure portals (banks, email, corporate VPN) from the infected machine until it has been completely wiped.

References & External Analysis

• Search "multibanker" on VirusTotal (External Analysis)

Frequently Asked Questions

Related Families (Category: trojan)

Explore other malware families in the same category:

• Wfpdisabler
• Njlogger
• Pcreviver
• Skypespam
• Bebloh

Machine-readable

Get this profile as JSON: https://jordanricky1604-ship-it.github.io/malware-families-catalog/api/multibanker.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.