This article was written by Greg Linares, principal threat intelligence analyst at Huntress.
Cybercriminals have found their new weapon of choice: infostealers. These stealthy malware strains are rapidly becoming the go-to tool for credential theft, data exfiltration, and network infiltration. Make no mistake, they pose a direct threat to you and your clients. Infostealers like Lumma, StealC, Redline, and Chromeloader are wreaking havoc by harvesting passwords, session tokens, and sensitive business data at an alarming scale. Notably, they accounted for nearly a quarter of all cyberthreats tracked by Huntress last year,
For MSPs, the stakes couldn’t be higher. A single stolen credential can grant cybercriminals access to entire networks, bypassing MFA protections and security controls. Worse yet, infostealers don’t just steal login information—they replicate user identities, allowing attackers to move laterally across systems undetected.
Recent events, such as infostealer source code leaks, misconfigured log files, and exposed command-and-control (C2) infrastructure, have shed light on the true scale of this threat. These incidents have provided defenders with invaluable intelligence but also underscore the increasing sophistication and widespread deployment of these tools.
We’ll break down how infostealers operate, why they’re so dangerous, and the critical steps you must take to safeguard your clients against this rising cyberthreat.
How Infostealers Work: The Stealthy Identity Theft Tool
Infostealers are lightweight, highly evasive malware that can operate as standalone applications or as part of larger malware families. Often disguised as legitimate software or executed in the background, their primary function is to harvest, decrypt, and exfiltrate sensitive user data. Key targets include:
- Browser-stored credentials and password managers. Advanced bypass techniques allow malware to extract passwords from memory or during the moment they are decrypted, such as when a user logs in.
- Session tokens and cookies. By stealing active sessions, attackers can hijack user accounts without requiring passwords or MFA, mimicking legitimate device-to-device authentication.
- Geolocation evasion tactics. Cybercriminals leverage VPNs, cloud-based systems, and geo-spoofing techniques to bypass security measures that rely on geographic-based restrictions.
- Registry keys, network shares, and sensitive files. Infostealers scour systems for additional credentials, configuration files, and network access points, often providing attackers with persistent access to broader infrastructure.
With these capabilities, attackers don’t just steal login credentials. They replicate user identities to evade security controls and infiltrate deeper into corporate networks.
Mitigating Infostealer Threats: A Multilayered Defense Approach
To defend against infostealers, MSPs and businesses must prioritize early detection, layered security, and credential hygiene. Key strategies include:
- Proactive credential monitoring. Implement credential canaries (decoy credentials strategically placed within an IT environment) to detect unauthorized access attempts in real time. Traditional breach monitoring services like Have I Been Pwned (HIBP) can help track exposed credentials. However, they often lag behind real-time theft events by months.
- Enforcing MFA and secure authentication. Prioritize hardware-based security keys and password managers with mobile-based authentication to reduce the effectiveness of stolen credentials.
- Detecting unauthorized access to protected storage. Enable security controls within EDR and XDR solutions to detect unauthorized access attempts on credential vaults, encrypted files, and session tokens.
- Securing MSP and tech support accounts. Attackers increasingly target MSPs, IT providers, and remote management platforms to exploit one-to-many access relationships. Compromising a single provider often leads to mass breaches across multiple businesses and clients.
Stay Ahead of Evolving Threats
When you have your clients adopt proactive detection, strong authentication, and strategic credential compartmentalization, you can minimize the damage inflicted by infostealers and reduce their attack surface against modern credential-theft campaigns.
Infostealers represent one of the most effective tools in a cybercriminal’s arsenal, and their impact is only growing. For MSPs and IT security professionals, the challenge is twofold. First, you must detect and mitigate infostealers before credentials are stolen. Second, you must ensure that one compromised account doesn’t lead to widespread network infiltration. With the right preventative strategies and security controls, you can stay ahead of this evolving threat landscape and protect your clients from large-scale identity compromise.
Related: 3 Security Conversations Every MSP Needs to Have with Clients
