Lynx
Table of Contents
Overview
Lynx (classified across antimalware engines under designations including Trojan:Win32/Lynx, Spyware:Win32/Lynx, and Trojan.Lynx) is a modular Windows infostealer and credential harvesting trojan active since 2017. Distributed primarily through spear-phishing campaigns with weaponized document attachments, deceptive cracking tools, and drive-by download vectors, Lynx specializes in extracting sensitive user authentication data from infected endpoints. Upon execution, Lynx conducts comprehensive system profiling, checking for virtualized analysis sandboxes and debuggers. It inspects local AppData paths of major Chromium- and Gecko-based browsers (including Google Chrome, Mozilla Firefox, Microsoft Edge, and Brave) to decrypt stored login passwords, cookies, credit card numbers, and autofill entries using the Windows CryptUnprotectData DPAPI function. In addition to web browsers, Lynx targets cryptocurrency wallet directories (such as Electrum, Exodus, and MetaMask extension storage), VPN configurations, and FTP client credentials (FileZilla). Collected credentials and system telemetry are bundled into a password-protected zip file and exfiltrated over HTTP POST or encrypted HTTPS to remote command-and-control servers.
Known aliases
Threat reports may refer to this family under multiple names:
Family Pedigree & Lineage
Malware authors regularly fork and iterate upon existing codebases. Observed upstream lineage and downstream variants for this family include:
Known Derivatives & Downstream Variants: Trojan:Win32/Lynx.A · Spyware:Win32/Lynx.B
MITRE ATT&CK Techniques
This family has been observed using the following ATT&CK techniques: T1555.003 · T1552.001 · T1082 · T1057 · T1041
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-EAF | Egress Analysis and Filtering | Isolate | T1041 | Enforce perimeter TLS inspection and alert on anomalous outbound data volume ratios transmitting over active C2 channels. |
D3-SDA | System Discovery Analysis | Detect | T1082 | Alert on rapid enumerations of systeminfo, hostname, and registry hardware trees in short intervals. |
D3-FPA | File Permission Auditing | Harden | T1552.001 | Scan filesystem repositories for plaintext configuration files and restrict access via Least Privilege RBAC controls. |
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. |
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_LYNX_T1_ARTIFACT {
meta:
description = "Tier 1 Primitive Artifact: Raw string matches for Lynx"
tier = "T1 - Primitive Artifact"
confidence = "Low-Medium (Fast Triage)"
author = "SystemHelpdesk Threat Research Desk"
date = "2026-10-14"
strings:
$s1 = "lynx" ascii wide nocase
$s2 = "trojan:win32/lynx" ascii wide nocase
$s3 = "spyware:win32/lynx" ascii wide nocase
$s4 = "trojan.lynx" ascii wide nocase
$s5 = "win32/lynx" ascii wide nocase
$s6 = "infostealer.lynx" 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 - Lynx (Infostealer) Execution & Triage
id: 725971ce-ab31-59df-bef6-00badfbf3441
status: production
description: Detects execution, defense evasion, and persistence behaviors associated
with the Lynx malware family. Detects browser credential database harvesting, master
key queries, and DPAPI extraction routines typical of modern infostealers.
references:
- https://malware-families-catalog.systemhelpdesk.com/families/lynx
- https://malware-families-catalog.systemhelpdesk.com/defensive/infostealer-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.infostealer
- author.ricky-jordan
- source.systemhelpdesk-mfc
- attack.t1555_003
- attack.t1552_001
- attack.t1082
- attack.t1057
- attack.t1041
logsource:
category: process_creation
product: windows
detection:
selection_process:
Image|endswith:
- \cmd.exe
- \powershell.exe
- \rundll32.exe
CommandLine|contains:
- \Google\Chrome\User Data\Default\Login Data
- \AppData\Roaming\Mozilla\Firefox\Profiles
- \AppData\Local\Microsoft\Edge\User Data
- vaultcmd.exe /list
- dpapi
condition: selection_process
falsepositives:
- Legitimate enterprise administrative scripts during approved change windows
- Authorized IT software deployment utilities and backup management agents
level: highTier 3 Attribution Fingerprint Rule (High Fidelity)
Deep signature matching distinctive operational fingerprints and payload characteristics.
rule MALWARE_WIN_LYNX_T3_ATTRIBUTION {
meta:
description = "Tier 3 Attribution Fingerprint: Heuristic detection for Lynx 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 = "lynx" 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
}References & External Analysis
- Microsoft Defender Threat Encyclopedia - Trojan:Win32/Lynx
- Trend Micro Threat Encyclopedia - Infostealer.Win32.Lynx
- Search "lynx" on VirusTotal (External Analysis)
- Search "lynx" on Any.Run (Sandbox Sandbox)
- Search "lynx" on MalwareBazaar (Malware Samples)
Frequently Asked Questions
What is Trojan:Win32/Lynx?
Lynx is a modular Windows information-stealing trojan designed to harvest web browser credentials, crypto wallets, and VPN tokens.
How does Lynx extract passwords stored in web browsers?
It parses SQLite databases within Chrome and Firefox AppData directories and decrypts Master Keys using Windows DPAPI (CryptUnprotectData).
What other sensitive information does Lynx steal?
It targets cryptocurrency wallet data (Electrum, MetaMask), FileZilla FTP credentials, OpenVPN profiles, and system hardware specifications.
How is Lynx delivered to victim endpoints?
It spreads via phishing emails with malicious document loaders, Trojanized freeware archives, and software crack utilities.
What are the recommended remediation actions for a Lynx infection?
Isolate the compromised computer, immediately revoke and reset all browser and corporate credentials from a secure device, and invalidate active session tokens.
How do I remove the Lynx Infostealer from Windows?
Manual removal of Lynx 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 Lynx a virus or a Infostealer?
Lynx is classified as a Infostealer. Unlike traditional viruses that infect files, modern malware like Lynx typically operates as a standalone payload designed to compromise systems, steal data, or deploy secondary stage implants.
What are the main symptoms of a Lynx infection?
Symptoms of Lynx 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 Infostealers
Want to prevent Lynx and similar threats from compromising your organization? Read our comprehensive defensive guide: InfoStealer Protection & Remediation.
📣 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
Get this profile as JSON: https://malware-families-catalog.systemhelpdesk.com/api/lynx.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.