capsule-proxy: Improper Authentication
CVE-2022-23652 is a high-severity improper authentication vulnerability in capsule-proxy from Clastix, with a CVSS 3.1 base score of 8.8 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. Affected capsule-proxy versions: < 0.2.1. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.4% chance of exploitation within 30 days, higher than 73% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of capsule-proxy you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Clastix | capsule-proxy | < 0.2.1 | 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
- HighAll data handled by the component can be read.
- 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:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.8 | High | CNA (github.com) |
| CVSS 3.1 | 8.8 | High | NVD |
| CVSS 2.0 | 6.5 | Medium | NVD |
Official description
capsule-proxy is a reverse proxy for Capsule Operator which provides multi-tenancy in Kubernetes. In versions prior to 0.2.1 an attacker with a proper authentication mechanism may use a malicious `Connection` header to start a privilege escalation attack towards the Kubernetes API Server. This vulnerability allows for an exploit of the `cluster-admin` Role bound to `capsule-proxy`. There are no known workarounds for this issue.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Authentication
When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.
How developers prevent this class of flaw
- Use an authentication framework or library such as the OWASP ESAPI Authentication feature.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
- github.com/clastix/capsule-proxy/security/advisories/GHSA-9cwv-cppx-mqjmThird Party Advisory
Patches and release notes
- github.com/clastix/capsule-proxy/commit/efe91f68ebf8a9e3d21491dc57da7b8a746415d8Third Party Advisory
Technical write-ups (may include proof of concept)
- github.com/clastix/capsule-proxy/issues/188Exploit, Issue Tracking, Third Party Advisory
Recent Improper Authentication vulnerabilities
- 9.8 Critical severity
- 9.8 Critical severity
- 7.5 High severity
- 9.1 Critical severity
- 7.5 High severity
- 8.8 High severity
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