CVE-2024-21662: 
Argo CD vulnerability analysis and mitigation

CVE-2024-21662 affects Argo CD, a declarative GitOps continuous delivery tool for Kubernetes. The vulnerability was discovered in March 2024 and allows attackers to bypass rate limit and brute force protections by exploiting the application's weak cache-based mechanism. This vulnerability affects versions prior to 2.8.13, 2.9.9, and 2.10.4 (GitHub Advisory).

The vulnerability exploits Argo CD's brute force protection mechanism which relies on a cache system that tracks login attempts for each user. The cache has a default maximum size of 1000 entries. An attacker can overflow this cache by bombarding it with login attempts for different users, effectively pushing out the admin account's failed attempts and resetting the rate limit for that account. The vulnerability has received a CVSS v3.1 base score of 9.1 CRITICAL from NIST NVD and 7.5 HIGH from GitHub (NVD).

This vulnerability enables attackers to perform brute force attacks at an accelerated rate, particularly targeting the default admin account. In proof-of-concept testing, attackers were able to perform approximately 230 brute force attempts on the admin account in just 15 minutes, allowing for roughly 1000 requests per hour and effectively bypassing previous rate limit protections (GitHub Advisory).

Users should upgrade to Argo CD version 2.8.13, 2.9.9, or 2.10.4 which contain patches for this vulnerability. The patch includes improvements to the cache mechanism and protection of the admin user from login attempt resets. For systems that cannot be immediately updated, implementing additional security measures such as using SSO integration instead of local users and ensuring Argo CD is not accessible from the public internet can help mitigate the risk (GitHub Advisory).

Security researchers and industry experts have expressed varying views about the seriousness of the vulnerability. While some consider it a major concern, particularly for SaaS services using Argo CD, others argue that the real-world risk is lower when standard security practices are followed. The disclosure process for this vulnerability took longer than the standard 90-day timeline, leading to discussions about improving the coordination of vulnerability disclosures and fixes for the project (TechTarget).