What Are Infostealers?
Infostealer malware, also known as information stealers, are a category of malicious software designed to harvest sensitive data from infected systems. Unlike ransomware that holds your data hostage, infostealers operate silently, exfiltrating credentials, cookies, cryptocurrency wallets, and other valuable information before victims even realize they've been compromised.
The Growing Threat Landscape
Over the past two years, we've witnessed an explosion in infostealer activity. Families like RedLine, Raccoon, Vidar, and the emerging Lumma stealer have become the weapons of choice for cybercriminals. According to our research at SocialEye, infostealer logs now account for a significant portion of compromised credentials appearing in underground markets.
Why Infostealers Are So Effective
- Low barrier to entry: Malware-as-a-Service (MaaS) models allow even novice attackers to deploy sophisticated stealers
- Stealth operations: Modern infostealers are designed to evade detection and operate without leaving obvious traces
- Comprehensive data theft: A single infection can yield browser passwords, session cookies, autofill data, and more
- Rapid monetization: Stolen data can be sold or exploited within hours of collection
Common Distribution Methods
Infostealers reach victims through various channels:
- Cracked software: Fake downloads of popular applications bundled with malware
- Phishing emails: Malicious attachments disguised as invoices, shipping notifications, or business documents
- Malvertising: Compromised ads leading to drive-by downloads
- Social engineering: Fake job offers, gaming cheats, or cryptocurrency tools
What Data Do They Steal?
Modern infostealers are comprehensive in their data collection:
Browser Data
- Saved passwords from Chrome, Firefox, Edge, and other browsers
- Session cookies that enable account takeover without knowing passwords
- Autofill information including addresses and credit cards
- Browsing history and bookmarks
System Information
- Hardware IDs and system specifications
- Installed software list
- Network configuration
- Screenshots of the desktop
Cryptocurrency
- Wallet files and private keys
- Browser extension data for hot wallets
- Exchange session tokens
Messaging & Social
- Discord tokens and session data
- Telegram session files
- Gaming platform credentials
Enterprise Impact
For organizations, a single employee infection can lead to:
- Credential compromise: VPN, email, and internal application access
- Session hijacking: Attackers bypass MFA using stolen cookies
- Data breaches: Access to sensitive corporate information
- Supply chain attacks: Compromised development environments
Detection and Prevention
For Individuals
- Use a reputable password manager instead of browser storage
- Enable MFA on all accounts (though be aware of cookie theft)
- Avoid downloading cracked software
- Keep antivirus updated and run regular scans
For Organizations
- Implement endpoint detection and response (EDR) solutions
- Monitor for credential exposure using services like SocialEye
- Enforce conditional access policies that detect anomalous sessions
- Regular security awareness training for employees
How SocialEye Helps
Our platform continuously monitors for credentials exposed through infostealer campaigns. When compromised data surfaces in stealer logs, we identify affected accounts and alert security teams, often before attackers can exploit the stolen information.
The stealer log database at SocialEye is updated in real-time, giving security professionals the earliest possible warning when their organization's credentials appear in the wild.
Conclusion
Infostealers represent a fundamental shift in the threat landscape. Their combination of stealth, comprehensive data collection, and ease of deployment makes them a persistent danger to both individuals and enterprises. Understanding how they work is the first step toward building effective defenses.
Stay vigilant, monitor for exposure, and remember that in today's threat environment, it's not a matter of if credentials will be compromised, but when—and how quickly you can respond.
Want to check if your organization has been affected by infostealer campaigns? Start a free trial of SocialEye to monitor your exposure.