CVE-2024-21652: Bypassing Brute Force Protection via Application Crash and In-Memory Data Loss

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
• EPSS 0.8%, percentile 54: FIRST’s model estimates a 0.8% chance of exploitation activity in the next 30 days, higher than 54% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Only applies if your dependency tree includes github.com/argoproj/argo-cd/v2 (Go) < 2.8.13, fixed in 2.8.13; github.com/argoproj/argo-cd/v2 (Go) >= 2.9.0, < 2.9.9, fixed in 2.9.9; github.com/argoproj/argo-cd/v2 (Go) >= 2.10.0, < 2.10.4, fixed in 2.10.4. Check your lockfile, including transitive dependencies.

What it is

Argo CD is a declarative, GitOps continuous delivery tool for Kubernetes. Prior to versions 2.8.13, 2.9.9, and 2.10.4, an attacker can exploit a chain of vulnerabilities, including a Denial of Service (DoS) flaw and in-memory data storage weakness, to effectively bypass the application's brute force login protection. This is a critical security vulnerability that allows attackers to bypass the brute force login protection mechanism. Not only can they crash the service affecting all users, but they can also make unlimited login attempts, increasing the risk of account compromise. Versions 2.8.13, 2.9.9, and 2.10.4 contain a patch for this issue.

From the GitHub advisory

Summary An attacker can exploit a chain of vulnerabilities, including a Denial of Service (DoS) flaw and in-memory data storage weakness, to effectively bypass the application's brute force login protection. This makes the application susceptible to brute force attacks, compromising the security of all user accounts.

Details The issue arises from two main vulnerabilities:

1. The application crashes due to a previously described DoS vulnerability caused by unsafe array modifications in a multi-threaded environment. 2. The application saves the data of failed login attempts in-memory, without persistent storage. When the application crashes and restarts, this data is lost, resetting the brute force protections.

By chaining these vulnerabilities, an attacker can circumvent the limitations placed on the number of login attempts.

PoC 1. Run the provided PoC script. 2. Observe that the script makes 6 login attempts, one more than the set limit of 5 failed attempts. 3. This is made possible because the script triggers a server restart via the DoS vulnerability after 5 failed attempts, thus resetting the counter for failed login attempts.

Weakness type: CWE-307.

Product: github.com/argoproj/argo-cd/v2 (Go) · Assigned by: GitHub_M · Published: 2024-03-18

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: none (no login)
• User interaction: none
• Scope: unchanged

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation poc, automatable yes, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.75% probability of exploitation activity in the next 30 days; percentile 54.

Timeline

• 2024-03-18 — CVE record published by GitHub_M
• 2024-03-18 — GitHub-reviewed advisory GHSA-x32m-mvfj-52xv published (critical)
• 2024-08-01 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-x32m-mvfj-52xv github.com
2. CVE.org record CVE-2024-21652 cve.org
3. NVD entry CVE-2024-21652 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com
3. github.com github.com
4. github.com github.com
5. argo-cd.readthedocs.io argo-cd.readthedocs.io

Critical Go advisories · Today’s Security Digest