func: Exposure of Sensitive Information to an Unauthorized Actor
CVE-2022-41939 is a high-severity exposure of sensitive information to an unauthorized actor vulnerability in func from Knative, with a CVSS 3.1 base score of 7.4 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. Affected func versions: < 1.8.1. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.99% chance of exploitation within 30 days, higher than 63% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Knative Func to 1.8.1 or a later version.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Knative | func | < 1.8.1 | Not stated |
| Linux Foundation | Knative Func | before 1.8.1 | 1.8.1 |
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
- NoneNo account or login is needed.
- User interaction
- RequiredA user must take an action such as opening a file or link.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 6.1 | Medium | CNA (github.com) |
| CVSS 3.1 | 7.4 | High | NVD |
Official description
knative.dev/func is is a client library and CLI enabling the development and deployment of Kubernetes functions. Developers using a malicious or compromised third-party buildpack could expose their registry credentials or local docker socket to a malicious `lifecycle` container. This issues has been patched in PR #1442, and is part of release 1.8.1. This issue only affects users who are using function buildpacks from third-parties; pinning the builder image to a specific content-hash with a valid `lifecycle` image will also mitigate the attack.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Exposure of Sensitive Information to an Unauthorized Actor
The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
How developers prevent this class of flaw
- Compartmentalize the system to have safe areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
More Exposure of Sensitive Information to an Unauthorized Actor vulnerabilities (CWE-200)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
- github.com/knative/func/security/advisories/GHSA-5336-2g3f-9g3mExploit, Third Party Advisory
Patches and release notes
- github.com/knative/func/pull/1442Third Party Advisory
- github.com/knative/func/releases/tag/knative-v1.8.1Release Notes, Third Party Advisory
Third-party and government advisories
Recent Exposure of Sensitive Information to an Unauthorized Actor vulnerabilities
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.8 High severity
- 7.6 High severity
- 7.5 High severity
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