Mokssteal
Table of Contents
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 our technical analysis hubs and the official MITRE ATT&CK framework:
| Technique | Name | Tactic | Official Spec |
|---|---|---|---|
T1555.003 | Credentials from Password Stores: Credentials from Web Browsers | Credential Access | ATT&CK ↗ |
T1539 | Steal Web Session Cookie | Credential Access | ATT&CK ↗ |
T1048.003 | Exfiltration Over Alternative Protocol (Telegram API / HTTP POST) | Exfiltration | ATT&CK ↗ |
T1562.001 | Impair Defenses: Disable or Modify Tools | Defense Evasion | ATT&CK ↗ |
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-NDF | Network Data Filtering | Isolate | T1048.003 | Inspect non-standard port traffic and block unauthorized ICMP or DNS tunneling protocols at the network perimeter. |
D3-CVH | Credential Vault Hardening | Harden | T1555.003 | Enable DPAPI master key audit logging and isolate browser SQLite database files within virtualization-based security containers. |
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_MOKSSTEAL_T1_ARTIFACT {
meta:
description = "Tier 1 Primitive Artifact: Raw string matches for Mokssteal"
tier = "T1 - Primitive Artifact"
confidence = "Low-Medium (Fast Triage)"
author = "SystemHelpdesk Threat Research Desk"
date = "2026-10-14"
strings:
$s1 = "mokssteal" 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 - Mokssteal (Trojan) Execution & Triage
id: b2e8871e-13af-5fd6-9ec5-560d4e18264e
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
with the Mokssteal 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/mokssteal
- 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.t1562_001
- attack.t1539
- attack.t1048_003
- attack.t1555_003
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_MOKSSTEAL_T3_ATTRIBUTION {
meta:
description = "Tier 3 Attribution Fingerprint: Heuristic detection for Mokssteal 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 = "mokssteal" 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.
- Instantly isolate the endpoint, though the exfiltration of credentials has likely already occurred within seconds of execution.
- Enforce a mandatory, immediate password reset for *every* account the user has saved in their browser, prioritizing corporate email, VPN, and SSO credentials.
- Revoke all active web session cookies for the user to prevent attackers from bypassing Multi-Factor Authentication (MFA) using stolen cookies.
- 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.
- Do not assume MFA will protect the compromised accounts; infostealers specifically target session cookies to perform 'Pass-the-Cookie' attacks, bypassing MFA entirely.
- 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)
- Search "mokssteal" on Any.Run (Sandbox Sandbox)
- Search "mokssteal" on MalwareBazaar (Malware Samples)
Frequently Asked Questions
What is Mokssteal and what threat category does it belong to?
Mokssteal is classified as a Trojan. Documented across security telemetry, it is engineered to execute unauthorized operations, establish persistent footholds on target endpoints, and facilitate malicious campaigns targeting enterprise and individual environments.
How does Mokssteal establish persistence and evade defensive controls?
Mokssteal typically establishes persistence through registry run keys, scheduled tasks, or service installations, while evading signature-based antivirus solutions through code obfuscation, memory injection, or anti-analysis sandbox checks.
What are the essential incident response steps for mitigating a Mokssteal compromise?
Security teams responding to Mokssteal should immediately isolate affected endpoints from the network, perform memory triage to capture volatile forensic artifacts, audit registry and startup persistence mechanisms, revoke exposed user credentials, and restore systems from verified, clean backups.
What secondary payloads and staging behaviors are commonly associated with Mokssteal?
Mokssteal frequently operates as a loader or dropper designed to establish a foothold before downloading and executing secondary high-impact malware payloads. Depending on the threat actor's objectives, these dropped modules can range from ransomware and banking injects to modular infostealers and remote management backdoors.
How can security operations teams effectively detect and hunt for Mokssteal across enterprise endpoints?
Defenders should hunt for Mokssteal by deploying behavioral endpoint detection and response (EDR) rules that monitor suspicious process spawning (such as cmd.exe or powershell.exe spawned from office documents or temporary directories), anomalous outbound network connections from non-browser binaries, and unauthorized modifications to Windows Run keys and scheduled task registries.
How do I remove the Mokssteal Trojan from Windows?
Manual removal of Mokssteal 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.
Is Mokssteal a virus or a Trojan?
Mokssteal is classified as a Trojan. Unlike traditional viruses that infect files, modern malware like Mokssteal typically operates as a standalone payload designed to compromise systems, steal data, or deploy secondary stage implants.
What are the main symptoms of a Mokssteal infection?
Symptoms of Mokssteal 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 Trojans
Want to prevent Mokssteal and similar threats from compromising your organization? Read our comprehensive defensive guide: Banking Trojan Protection for Businesses.
📣 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
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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.