Cloud Controller API: Improper Certificate Validation
CVE-2023-20881 is a high-severity improper certificate validation vulnerability in Cloud Controller API, with a CVSS 3.1 base score of 8.1 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. There is no confirmed exploitation so far. EPSS estimates a 0.36% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of Cloud Controller API you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on cloudfoundry.org for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Cloud Controller API | Cloud Controller API | Not specified in the record | Not stated |
| Cloudfoundry | Capi-release | 1.140 through 1.152.0 | Not stated |
| Cloudfoundry | Cf-deployment | 24.7.0 through 29.0.0 | Not stated |
| Cloudfoundry | Loggregator-agent | 7.0 through 7.2.1 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.1 | High | NVD |
| CVSS 3.1 | 8.1 | High | CISA (ADP) |
Official description
Cloud foundry instances having CAPI version between 1.140 and 1.152.0 along with loggregator-agent v7+ may override other users syslog drain credentials if they're aware of the client certificate used for that syslog drain. This applies even if the drain has zero certs. This would allow the user to override the private key and add or modify a certificate authority used for the connection.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Certificate Validation
The product does not validate, or incorrectly validates, a certificate.
How developers prevent this class of flaw
- Certificates should be carefully managed and checked to assure that data are encrypted with the intended owner's public key.
- If certificate pinning is being used, ensure that all relevant properties of the certificate are fully validated before the certificate is pinned, including the hostname.
More Improper Certificate Validation vulnerabilities (CWE-295)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Recent Improper Certificate Validation vulnerabilities
- 7.5 High severity
- 7.5 High severity
- 8.1 High severity
- 9.8 Critical severity
- 8.1 High severity
- 8.8 High severity
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