Race Condition in Argo CD SessionManager Enables Brute Force Attacks

Executive Summary

This vulnerability is a race condition in Argo CD's SessionManager that allows attackers to bypass rate limiting. Normally, the system limits failed login attempts to 5 in 5 minutes, but due to the race condition, multiple concurrent requests for the same username can all read the failure count before any updates it. This enables brute force attacks by processing more attempts than allowed.

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Detection Guidance

Monitor login attempts and rate limiting logs for Argo CD. Check for multiple concurrent failed login attempts from the same IP or username that exceed the configured limit of 5 failures in 5 minutes. Use Argo CD logs or Kubernetes audit logs to identify unusual patterns.

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Impact Analysis

Attackers can exploit this to bypass login rate limits and perform brute force attacks on local accounts, including the built-in admin account. This could lead to unauthorized access to Argo CD and potentially the Kubernetes cluster it manages.

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Compliance Impact

This vulnerability could lead to unauthorized access, potentially violating data protection requirements under GDPR or HIPAA. Unauthorized access may result in data breaches, requiring notifications and investigations under these regulations.

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Mitigation Strategies

• Upgrade Argo CD to patched versions v3.3.15, v3.4.10, v3.5.4, or v3.6.0-rc2 or later.
• Disable local accounts and enforce SSO or OIDC authentication if possible.
• Restrict network access to the Argo CD API to limit exposure.

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