talos: Incorrect Authorization
CVE-2022-36103 is a high-severity incorrect authorization vulnerability in talos from Siderolabs, 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 talos versions: < 1.2.2. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.71% chance of exploitation within 30 days, higher than 54% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Talos Linux to 1.2.2 or a later version.
- Read the advisory on github.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Siderolabs | talos | < 1.2.2 | Not stated |
| Siderolabs | Talos Linux | before 1.2.2 | 1.2.2 |
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 | 7.2 | High | CNA (github.com) |
| CVSS 3.1 | 8.8 | High | NVD |
Official description
Talos Linux is a Linux distribution built for Kubernetes deployments. Talos worker nodes use a join token to get accepted into the Talos cluster. Due to improper validation of the request while signing a worker node CSR (certificate signing request) Talos control plane node might issue Talos API certificate which allows full access to Talos API on a control plane node. Accessing Talos API with full level access on a control plane node might reveal sensitive information which allows full level access to the cluster (Kubernetes and Talos PKI, etc.). Talos API join token is stored in the machine configuration on the worker node. When configured correctly, Kubernetes workloads don't have access to the machine configuration, but due to a misconfiguration workload might access the machine configuration and reveal the join token. This problem has been fixed in Talos 1.2.2. Enabling the Pod Security Standards mitigates the vulnerability by denying hostPath mounts and host networking by default in the baseline policy. Clusters that don't run untrusted workloads are not affected. Clusters with correct Pod Security configurations which don't allow hostPath mounts, and secure access to cloud metadata server (or machine configuration is not supplied via cloud metadata server) are not affected.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Incorrect Authorization
The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.
How developers prevent this class of flaw
- Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) to enforce the roles at the appropriate boundaries. Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
- Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records. For example, a database may restrict access for medical records to a specific database user, but each record might only be intended to be accessible to the patient and the patient's doctor.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using authorization frameworks such as the JAAS Authorization Framework and the OWASP ESAPI Access Control feature.
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
- github.com/siderolabs/talos/security/advisories/GHSA-7hgc-php5-77qqMitigation, Third Party Advisory
Patches and release notes
- github.com/siderolabs/talos/commit/9eaf33f3f274e746ca1b442c0a1a0dae0cec088fThird Party Advisory
- github.com/siderolabs/talos/releases/tag/v1.2.2Release Notes, Third Party Advisory
Recent Incorrect Authorization vulnerabilities
- 7.1 High severity
- 7.1 High severity
- 9.8 Critical severity
- 8.1 High severity
- 8.8 High severity
- 8.8 High severity
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