Mokssteal

Overview

PWS:Win32/Mokssteal is a highly specialized Password Stealer (PWS) and Information Stealer (Infostealer) trojan designed to silently harvest and exfiltrate credentials, cookies, and sensitive configuration files from infected endpoints. Unlike generic trojans, Mokssteal specifically targets web browser password stores, FTP clients, and email applications, packaging the stolen data for rapid sale on underground cybercriminal forums (like Genesis Market or Russian Market).

Understanding the Mokssteal Infostealer
To an end-user, a Mokssteal infection is entirely invisible. There are no pop-ups, no ransom notes, and the system continues to function normally. For a security analyst, a Mokssteal detection is a 'code red' credential compromise event. The malware is designed for rapid execution; it 'smash and grabs' the credentials and immediately exfiltrates them, often completing its objective within seconds of execution.

Execution and Exfiltration Mechanics
Mokssteal is typically distributed via weaponized phishing attachments (like macro-enabled Office documents or malicious PDFs) (`T1566.001`) or as a secondary payload dropped by an Initial Access Broker. Upon execution (`T1204.002`), it attempts to evade detection by disabling Windows Defender (`T1562.001`). It then systematically queries the SQLite databases used by Chromium-based and Firefox browsers to store saved passwords, cookies, and autofill data (`T1555.003`). It also targets the configuration files of FTP clients (like FileZilla) and email clients (like Outlook or Thunderbird) (`T1552.001`). The harvested data is compressed into a ZIP archive and exfiltrated via HTTP POST requests to a Command and Control (C2) server or dropped directly into a Telegram bot channel (`T1048.003`).

Indicators of Compromise & Impact
The primary impact is the catastrophic loss of user credentials and session cookies, which frequently leads to Account Takeover (ATO) and lateral movement into corporate networks. EDR logs will flag an anomalous process accessing multiple browser database files (`Login Data`, `Cookies`) in rapid succession. Network IoCs include a brief burst of outbound HTTP/HTTPS traffic or Telegram API connections containing an encrypted archive immediately following the execution of an unknown binary.

MITRE ATT&CK Techniques

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

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

Sigma Rule

title: Suspicious Mokssteal Activity
id: cf41c27de6dcb9ee744334fed672cf0c
status: experimental
description: Detects generic indicators of the mokssteal malware family.
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith:
            - '\cmd.exe'
            - '\powershell.exe'
        CommandLine|contains:
            - "*mokssteal*"
    condition: selection
level: medium

Containment & Response Steps

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

1. Instantly isolate the endpoint, though the exfiltration of credentials has likely already occurred within seconds of execution.
2. Enforce a mandatory, immediate password reset for *every* account the user has saved in their browser, prioritizing corporate email, VPN, and SSO credentials.
3. Revoke all active web session cookies for the user to prevent attackers from bypassing Multi-Factor Authentication (MFA) using stolen cookies.
4. Use EDR to locate and terminate the Mokssteal process and remove any dropped persistence mechanisms.

What to Avoid

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

1. Do not assume MFA will protect the compromised accounts; infostealers specifically target session cookies to perform 'Pass-the-Cookie' attacks, bypassing MFA entirely.
2. Avoid focusing solely on malware removal; the primary incident response must focus on credential revocation and monitoring for anomalous logins.

References & External Analysis

• Search "mokssteal" on VirusTotal (External Analysis)

Frequently Asked Questions

Related Families (Category: trojan)

Explore other malware families in the same category:

• Revenge
• Schoolgirl
• Onesystemcare
• Startp
• Qadars

Machine-readable

Get this profile as JSON: https://jordan123234-malware-families-explorer.static.hf.space/api/mokssteal.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.