Summary Points
- Threat actors in early 2025 shifted from malware-based attacks to using stolen credentials and legitimate access to infiltrate networks across various industries.
- The primary attack vectors include exploiting VPNs, public-facing applications with vulnerabilities, and purchasing compromised credentials from underground markets.
- Once inside, attackers use manual lateral movement techniques (RDP, SMB, WinRM) and privilege escalation tools like Mimikatz and Zerologon to maintain persistence and evade detection.
- Data exfiltration is carried out via covert file transfers through remote tools, while the lack of multi-factor authentication on VPNs accelerates rapid ransomware deployment, making detection more challenging.
Key Challenge
In the first half of 2025, financially driven cybercriminals significantly shifted their tactics, moving away from deploying complex malware to using stolen credentials for network infiltration. These threat actors primarily gain access through compromised VPN accounts, obtained either via phishing, underground credential markets, or reuse of passwords, with stolen credentials costing anywhere from $100 to $20,000 depending on the target’s size and location. Once inside, they execute manual lateral movements utilizing legitimate tools like RDP, SMB, and WinRM, which makes detection difficult as their activities mimic legitimate administrator actions. They maintain persistence by installing remote management tools and exploiting account privileges through methods such as Mimikatz and Zerologon, then transfer data through direct file transfers, often bypassing traditional detection mechanisms. This approach, characterized by its low cost and high success rate, enables attackers to remain undetected longer, covertly exfiltrating data and conducting ransomware operations, according to the FortiGuard Incident Response team, which observed these patterns across multiple industries.
What’s at Stake?
Stolen credentials and the hijacking of legitimate accounts are powerful tools used by cybercriminals to launch financially motivated attacks that can devastate any business. When hackers successfully obtain login details, they can infiltrate systems, siphon funds, commit fraud, or manipulate sensitive data, all while masquerading as trusted employees or customers. The repercussions are severe: financial losses, reputational damage, operational disruptions, and erosion of customer trust. Small businesses are as vulnerable as large corporations, often lacking the robust security measures necessary to defend against such threats. Ultimately, unchecked credential theft can lead to a cycle of ongoing attacks and financial drain, highlighting the urgent need for strong authentication practices and vigilant monitoring to safeguard your business’s assets and credibility.
Possible Actions
Early and effective response to stolen credentials and valid account abuse is essential to minimizing financial damage, preventing further unauthorized access, and maintaining organizational trust. Rapid remediation helps contain breaches quickly, reducing the window of opportunity for attackers and limiting overall impact.
Mitigation Strategies
- Implement multi-factor authentication (MFA) to add an extra layer of security.
- Employ strong, unique password policies combined with regular rotation.
- Monitor for suspicious login activity and abnormal account behavior.
- Enforce account lockout policies after failed login attempts.
Remediation Actions
- Immediately disable compromised accounts to prevent further misuse.
- Conduct password resets for affected accounts.
- Perform comprehensive user activity audits to identify scope of access.
- Deploy targeted user awareness training regarding credential security.
- Enhance threat detection mechanisms to identify credential-related attacks early.
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Disclaimer: The information provided may not always be accurate or up to date. Please do your own research, as the cybersecurity landscape evolves rapidly. Intended for secondary references purposes only.
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