5 Medium
CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
PARTIAL
Availability Impact
NONE
AV:N/AC:L/Au:N/C:N/I:P/A:N
9.8 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5 High
AI Score
Confidence
Low
0.002 Low
EPSS
Percentile
52.7%
An attacker can effectively bypass the rate limit and brute force protections by exploiting the application’s weak cache-based mechanism. This loophole in security can be combined with other vulnerabilities to attack the default admin account. This flaw undermines a previously patched CVE intended to protect against brute-force attacks.
The application’s brute force protection relies on a cache mechanism that tracks login attempts for each user. This cache is limited to a defaultMaxCacheSize
of 1000 entries. An attacker can overflow this cache by bombarding it with login attempts for different users, thereby pushing out the admin account’s failed attempts and effectively resetting the rate limit for that account.
The brute force protection mechanism’s code:
if failed && len(failures) >= getMaximumCacheSize() {
log.Warnf("Session cache size exceeds %d entries, removing random entry",
getMaximumCacheSize())
idx := rand.Intn(len(failures) - 1)
var rmUser string
i := 0
for key := range failures {
if i == idx {
rmUser = key
delete(failures, key)
break
}
i++ }
log.Infof("Deleted entry for user %s from cache", rmUser)
}
In just 15 minutes, the PoC was able to perform 230 brute force attempts on the admin account. This rate allows for approximately 1000 requests per hour, effectively rendering the older CVE rate limit patches useless.
This is a severe vulnerability that enables attackers to perform brute force attacks at an accelerated rate, especially targeting the default admin account.
argo-cd.readthedocs.io/en/stable/security_considerations/#cve-2020-8827-insufficient-anti-automationanti-brute-force
github.com/argoproj/argo-cd
github.com/argoproj/argo-cd/commit/17b0df1168a4c535f6f37e95f25ed7cd81e1fa4d
github.com/argoproj/argo-cd/commit/6e181d72b31522f886a2afa029d5b26d7912ec7b
github.com/argoproj/argo-cd/commit/cebb6538f7944c87ca2fecb5d17f8baacc431456
github.com/argoproj/argo-cd/security/advisories/GHSA-2vgg-9h6w-m454
nvd.nist.gov/vuln/detail/CVE-2024-21662
5 Medium
CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
PARTIAL
Availability Impact
NONE
AV:N/AC:L/Au:N/C:N/I:P/A:N
9.8 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5 High
AI Score
Confidence
Low
0.002 Low
EPSS
Percentile
52.7%