GHSA-4fc7-hc63-7fjg CVE-2021-36778
Exposure of repository credentials to external third-party sources in Rancher
- Severity
- 8.3 / 10
- High · CVSS 3.1
- Exploit chance (EPSS)
- 0.76%
- Chance of exploitation in the next 30 days. Higher than 55.18% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
- CWE-522 Insufficiently Protected Credentials
- CWE-863 Incorrect Authorization
- Fix
2.6.3- Upgrade github.com/rancher/rancher to this version or later
Description
Impact
This issue only happens when the user configures access credentials to a private repository in Rancher inside Apps & Marketplace > Repositories. It affects Rancher versions 2.5.0 up to and including 2.5.11 and from 2.6.0 up to and including 2.6.2.
An insufficient check of the same-origin policy when downloading Helm charts from a configured private repository can lead to exposure of the repository credentials to a third-party provider. This exposure happens when the private repository:
- Does an HTTP redirect to a third-party repository or external storage provider.
- Downloads an icon resource for the chart hosted on a third-party provider.
The address of the private repository is not leaked, only the credentials are leaked in the HTTP Authorization header in base64 format.
With the patched versions, the default behavior now is to only send the private repository credentials when subdomain or domain hostname match when following the redirect or downloading external resources.
Patches
Patched versions include releases 2.5.12, 2.6.3 and later versions.
Workarounds
- Update Rancher to a patched version.
- Check the Helm charts in your configured private repository for possible redirects to third-party storage, and for Helm chart icons from third-party sources.
- Evaluate any Helm chart that might lead to the mentioned scenario and change affected credentials if deemed necessary.
References
Information about the same-origin check and how to disable it is available in Rancher documentation.
For more information
If you have any questions or comments about this advisory:
- Reach out to SUSE Rancher Security team for security related inquiries.
- Open an issue in Rancher repository.
- Verify our support matrix and product support lifecycle.
Affected versions
Go
| Package | Vulnerable | Fixed in |
|---|---|---|
| github.com/rancher/rancher | >= 2.6.0, < 2.6.3 |
2.6.3 |
| github.com/rancher/rancher | >= 2.5.0, < 2.5.12 |
2.5.12 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
github.com/rancher/rancher Go → 2.6.3
- go
go get github.com/rancher/rancher@v2.6.3 && go mod tidy
Severity breakdown
CVSS 3.1 8.3
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:L
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- Low
Weakness
CWE-200: 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 to prevent it
- Architecture and Design: 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.
CWE-522: Insufficiently Protected Credentials
The product transmits or stores authentication credentials, but it uses an insecure method that is susceptible to unauthorized interception and/or retrieval.
How to prevent it
- Architecture and Design: Use an appropriate security mechanism to protect the credentials.
- Architecture and Design: Make appropriate use of cryptography to protect the credentials.
- Implementation: Use industry standards to protect the credentials (e.g. LDAP, keystore, etc.).
CWE-863: 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 to prevent it
- Architecture and Design: 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) [REF-229] 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.
- Architecture and Design: 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 [REF-7].
- Architecture and Design: 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 [REF-233] and the OWASP ESAPI Access Control feature [REF-45].
- Architecture and Design: For web applications, make sure that the access control mechanism is enforced correctly at the server side on every page. Users should not be able to access any unauthorized functionality or information by simply requesting direct access to that page. One way to do this is to ensure that all pages containing sensitive information are not cached, and that all such pages restrict access to requests that are accompanied by an active and authenticated session token associated with a user who has the required permissions to access that page.
- System Configuration, Installation: Use the access control capabilities of your operating system and server environment and define your access control lists accordingly. Use a "default deny" policy when defining these ACLs.
References
Advisories
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-4j6x-2764-m8gh Rancher has over-inclusive team membership expansion in GitHub App authentication provider | High | Also affects github.com/rancher/rancher |
| GHSA-vx8h-4prv-g744 Rancher has Privilege Escalation from Project Owner to Host | High | Also affects github.com/rancher/rancher |
| GHSA-mhc6-2gfq-xx62 Rancher vulnerable to command injection through unsanitized YAML parameter | Critical | Also affects github.com/rancher/rancher |
| GHSA-5v3h-x4wf-5c35 Rancher Extensions have arbitrary file access via path traversal | High | Also affects github.com/rancher/rancher |
| GHSA-gqf8-rvrh-g7w6 Rancher cloud credentials can be used through proxy API by users without access | Critical | Also affects github.com/rancher/rancher |
| GHSA-hwm2-4ph6-w6m5 Rancher's restricted PodSecurityPolicy does not prevent containers from running as a privileged user | High | Also affects github.com/rancher/rancher |
| GHSA-mc24-7m59-4q5p Rancher CLI skips TLS verification on Rancher CLI login command | Medium | Also affects github.com/rancher/rancher |
| GHSA-mw39-9qc2-f7mg Rancher exposes sensitive information through audit logs | Medium | Also affects github.com/rancher/rancher |
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