November 21, 2024 at 09:39AM
A design flaw in Fortinet’s VPN logging mechanism allows successful credential verifications during brute-force attacks to go unlogged. Researchers from Pentera discovered that halting the login process post-authentication prevents successful attempts from being recorded, risking undetected breaches. Fortinet does not classify the issue as a vulnerability.
### Meeting Takeaways:
1. **Design Flaw Identified**: A vulnerability in the Fortinet VPN server’s logging mechanism has been discovered, enabling attackers to conceal successful credential verifications during brute-force attacks.
2. **Logging Mechanism Details**:
– The FortiClient VPN server employs a two-step process for logging: authentication and authorization.
– Successful logins are recorded only if both steps are passed; if the process stops after authentication, only failed attempts are logged.
3. **Research Findings**:
– Pentera, a cybersecurity firm, detailed a method to halt the login process post-authentication, preventing successful login attempts from being logged.
– Successful credentials can be identified without generating logs, creating a significant security risk.
4. **Security Implications**:
– This flaw allows attackers to execute brute-force attacks without detection of success, leading incident response teams to be unaware if attacks were successful.
– Failed attempts can still alert Fortinet administrators to potential attacks, but successful verifications remain undetected.
5. **Potential for Credential Theft**: Successfully verified credentials could be sold or used later for unauthorized access, especially when oversight decreases.
6. **Complications in Attacks**: Even with successful authentication, attackers face additional hurdles due to FortiClient VPN’s security compliance and access level checks before completing the authorization process.
7. **Response from Fortinet**: Pentera shared their research with Fortinet, which did not acknowledge the issue as a vulnerability. Future actions from Fortinet regarding this flaw remain uncertain, despite the fix not being complicated.
8. **Action Items**:
– Continue monitoring for updates from Fortinet regarding this issue.
– Consider additional security measures to safeguard against potential brute-force attacks exploiting this vulnerability.