Stolen Credentials: The Rising Threat to Network Security and How to Defend Against It

Cybercriminals are increasingly bypassing complex exploits in favor of a simpler tactic: logging in with stolen credentials. According to IBM X-Force, attacks leveraging valid credentials surged by 71% year-over-year in 2024¹. This shift underscores a critical vulnerability in modern defenses—attackers no longer need zero-days when they can walk through the front door.

The Credential Threat Landscape

Stolen credentials have become a primary attack vector, with 50% of UK breaches originating from valid account exploitation¹. The underground market for credentials thrives, with infostealer malware like Lumma and RisePro selling logins for $1–$10 each. Attackers employ methods such as password spraying against Microsoft 365, adversary-in-the-middle (AiTM) phishing kits to bypass multi-factor authentication (MFA), and brute-forcing VPN portals linked to ransomware groups like Black Basta¹.

SaaS and Cloud Vulnerabilities

Cloud environments are particularly vulnerable. A review of 230 billion SaaS audit logs revealed attackers exfiltrate data within 30 minutes of compromise, often targeting Microsoft 365 via Chinese AS networks (AS 4134, AS 4837)². Despite this, 73% of companies lack effective Zero Trust implementations, leaving gaps in defense².

Defense Strategies

To counter credential-based threats, organizations must adopt layered defenses. Key recommendations include enforcing phishing-resistant MFA (FIDO2), screening passwords against breach databases, and monitoring SaaS logs for anomalous activity⁵. Zero Trust principles—such as “never trust, always verify”—are critical, especially in multi-cloud environments where 40% of breaches occur⁴.

Emerging Trends

AI-driven attacks are escalating, with groups like Hive0137 using large language models (LLMs) to craft convincing phishing emails⁴. Russian hackers have also bypassed Gmail MFA using app-specific passwords, highlighting evolving tactics⁶.

Conclusion

Stolen credentials represent a low-effort, high-reward attack method. Defenders must prioritize real-time credential screening, Zero Trust adoption, and staff training to mitigate risks. As attackers refine their techniques, proactive measures will be essential to secure networks.

References

1. [1] IBM X-Force, “Credential-Based Cyber Threats: Key Insights & Defenses,” 2024. [Online]. Available: https://www.ibm.com/reports/threat-intelligence.
2. [2] AppOmni, “SaaS Security Report,” 2024. [Online]. Available: https://www.appomni.com.
3. [3] Outpost24, “Credential Theft: The Business Impact,” 2024. [Online]. Available: https://outpost24.com/blog/credential-theft-the-business-impact-of-stolen-credentials.
4. [4] IBM X-Force, “Emerging Threats in 2024,” 2024. [Online]. Available: https://www.ibm.com/security.
5. [5] Osterman Research, “Zero Trust Implementation,” 2024. [Online]. Available: https://resources.enzoic.com/osterman-talk-about-mfa.
6. [6] SecurityWeek, “Russian Hackers Bypass Gmail MFA,” 2024. [Online]. Available: https://www.securityweek.com/russian-hackers-bypass-gmail-mfa-with-app-specific-password-ruse.