Full Report
2025-05-21 • Trendmicro • Junestherry Dela Cruz • win.stealc, win.vidar Open article on Malpedia
Analysis Summary
# Tool/Technique: Vidar and StealC Infostealers
## Overview
This summary covers the Vidar and StealC malware families which are being distributed via malicious entities posing as sources of pirated applications advertised through TikTok videos. These threats are primarily information stealers designed to exfiltrate sensitive data from infected systems.
## Technical Details
- Type: Malware family (Infostealer)
- Platform: Windows
- Capabilities: Stealing sensitive information such as credentials, cryptocurrency wallets, and cookies/session data from browsers, email clients, and FTP clients.
- First Seen: Not specified in the provided context, but used in recent campaigns.
## MITRE ATT&CK Mapping
Since the specific techniques aren't detailed in the context, the mapping below reflects the general actions of an information stealer:
- **TA0010 - Exfiltration**
- T1041 - Exfiltration Over C2 Channel
- **TA0005 - Defense Evasion**
- T1027 - Obfuscated Files or Information (Common for malware delivery)
- **TA0003 - Persistence**
- T1544.003 - Registry Run Keys / Startup Folder (Common persistence mechanism for stealers)
## Functionality
### Core Capabilities
- Theft of saved credentials from various applications (browsers, mail clients, FTP clients).
- Targeting of cryptocurrency wallet files and data.
- Collection of browser cookies and session information.
### Advanced Features
- **Vidar and StealC:** Both are known for their wide data collection scope, often employing encryption or obfuscation to hide communications and stolen data during exfiltration.
## Indicators of Compromise
- File Hashes: [Not provided in context]
- File Names: [Not provided in context]
- Registry Keys: [Not provided in context (Likely uses standard persistence locations)]
- Network Indicators: [C2 information is typically present but not provided in this summary context. Indicators would normally include C2 IP addresses or domains.]
- Behavioral Indicators: Abnormal outbound network traffic originating from newly dropped executables; querying browser credential stores; modification of startup locations.
## Associated Threat Actors
- Threat actors using social media platforms (specifically TikTok in this context) to rapidly distribute malware disguised as pirated software. Specific named groups are not mentioned in the provided text.
## Detection Methods
- Signature-based detection: Signatures for known Vidar and StealC binaries.
- Behavioral detection: Monitoring processes attempting to access credential stores (`logins.json`, SQLite databases, OS credential managers) or perform large unauthorized file uploads.
- YARA rules: Available for known file structures or embedded strings associated with these malware families.
## Mitigation Strategies
- **User Education:** Caution against downloading software from unofficial or untrusted sources advertised on social media platforms (e.g., TikTok).
- **Application Whitelisting:** Restrict execution of unauthorized applications.
- **Patching/Updating:** Ensure security software and operating systems are up-to-date.
- **Network Monitoring:** Monitor for unusual high-volume outbound connections, especially over non-standard ports or to suspicious IP ranges (C2 communication).
## Related Tools/Techniques
- **Vidar:** Successor or competitor to older stealers like IcedID or Vidar (itself evolving from other lines).
- **StealC:** Often seen alongside other commodity malware strains.
- **Campaign Vehicle:** Social engineering via TikTok videos promising pirated software or "cracks."