GHSA-q4w5-4gq2-98vm CVE-2022-31036 GO-2022-0499
Symlink following allows leaking out-of-bounds YAML files from Argo CD repo-server
Medium
Go
- Severity
- 4.3 / 10
- Medium · CVSS 3.1
- Exploit chance (EPSS)
- 0.89%
- Chance of exploitation in the next 30 days. Higher than 59.41% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-20 Improper Input Validation
- CWE-59 Improper Link Resolution Before File Access ('Link Following')
- Fix
- Available
- 2 packages have a fixed version
Description
Impact
All unpatched versions of Argo CD starting with v1.3.0 are vulnerable to a symlink following bug allowing a malicious user with repository write access to leak sensitive YAML files from Argo CD's repo-server.
A malicious Argo CD user with write access for a repository which is (or may be) used in a Helm-type Application may commit a symlink which points to an out-of-bounds file. If the target file is a valid YAML file, the attacker can read the contents of that file.
Sensitive files which could be leaked include manifest files from other Applications' source repositories (potentially decrypted files, if you are using a decryption plugin) or any YAML-formatted secrets which have been mounted as files on the repo-server.
Patches
A patch for this vulnerability has been released in the following Argo CD versions:
- v2.4.1
- v2.3.5
- v2.2.10
- v2.1.16
Workarounds
- If you are using >=v2.3.0 and do not have any Helm-type Applications, disable the Helm config management tool.
Mitigations
- Avoid mounting YAML-formatted secrets as files on the repo-server.
- Upgrade to >=2.3.0 to significantly reduce the risk of leaking out-of-bounds manifest files. Starting with 2.3.0, repository paths are randomized, and read permissions are restricted when manifests are not being actively being generated. This makes it very difficult to craft and use a malicious symlink.
Best practices which can mitigate risk
- Limit who has push access to manifest repositories.
- Limit who is allowed to configure new source repositories.
Credits
Disclosed by ADA Logics in a security audit of the Argo project sponsored by CNCF and facilitated by OSTIF. Thanks to Adam Korczynski and David Korczynski for their work on the audit.
References
- List of types of Applications, including Helm-type
- RBAC documentation, showing how to limit repository permissions
For more information
- Open an issue in the Argo CD issue tracker or discussions
- Join us on Slack in channel #argo-cd
Affected versions
Go
| Package | Vulnerable | Fixed in |
|---|---|---|
| github.com/argoproj/argo-cd | >= 1.3.0, < 2.1.16 |
2.1.16 |
| github.com/argoproj/argo-cd | >= 1.3.0 |
No fix yet |
| github.com/argoproj/argo-cd/v2 | < 2.1.16 |
2.1.16 |
| github.com/argoproj/argo-cd/v2 | >= 2.2.0, < 2.2.10 |
2.2.10 |
| github.com/argoproj/argo-cd/v2 | >= 2.3.0, < 2.3.5 |
2.3.5 |
| github.com/argoproj/argo-cd/v2 | >= 2.4.0, < 2.4.1 |
2.4.1 |
| github.com/argoproj/argo-cd/v2 | < 2.1.16>= 2.2.0, < 2.2.10>= 2.3.0, < 2.3.5>= 2.4.0, < 2.4.1 |
2.1.162.2.102.3.52.4.1 |
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/argoproj/argo-cd Go → 2.1.16
- go
go get github.com/argoproj/argo-cd@v2.1.16 && go mod tidy
github.com/argoproj/argo-cd/v2 Go → 2.1.16
- go
go get github.com/argoproj/argo-cd/v2@v2.1.16 && go mod tidy
Severity breakdown
CVSS 3.1 4.3
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
Weakness
CWE-20: Improper Input Validation
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
How to prevent it
- Architecture and Design: Consider using language-theoretic security (LangSec) techniques that characterize inputs using a formal language and build "recognizers" for that language. This effectively requires parsing to be a distinct layer that effectively enforces a boundary between raw input and internal data representations, instead of allowing parser code to be scattered throughout the program, where it could be subject to errors or inconsistencies that create weaknesses. [REF-1109] [REF-1110] [REF-1111]
- Architecture and Design: Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
- Architecture and Design, Implementation: Understand all the potential areas where untrusted inputs can enter the product, including but not limited to: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls.
- Implementation: Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does. When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue." Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
- Architecture and Design: For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server. Even though client-side checks provide minimal benefits with respect to server-side security, they are still useful. First, they can support intrusion detection. If the server receives input that should have been rejected by the client, then it may be an indication of an attack. Second, client-side error-checking can provide helpful feedback to the user about the expectations for valid input. Third, there may be a reduction in server-side processing time for accidental input errors, although this is typically a small savings.
- Implementation: When your application combines data from multiple sources, perform the validation after the sources have been combined. The individual data elements may pass the validation step but violate the intended restrictions after they have been combined.
- Implementation: Be especially careful to validate all input when invoking code that crosses language boundaries, such as from an interpreted language to native code. This could create an unexpected interaction between the language boundaries. Ensure that you are not violating any of the expectations of the language with which you are interfacing. For example, even though Java may not be susceptible to buffer overflows, providing a large argument in a call to native code might trigger an overflow.
- Implementation: Directly convert your input type into the expected data type, such as using a conversion function that translates a string into a number. After converting to the expected data type, ensure that the input's values fall within the expected range of allowable values and that multi-field consistencies are maintained.
- Implementation: Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180, CWE-181). Make sure that your application does not inadvertently decode the same input twice (CWE-174). Such errors could be used to bypass allowlist schemes by introducing dangerous inputs after they have been checked. Use libraries such as the OWASP ESAPI Canonicalization control. Consider performing repeated canonicalization until your input does not change any more. This will avoid double-decoding and similar scenarios, but it might inadvertently modify inputs that are allowed to contain properly-encoded dangerous content.
- Implementation: When exchanging data between components, ensure that both components are using the same character encoding. Ensure that the proper encoding is applied at each interface. Explicitly set the encoding you are using whenever the protocol allows you to do so.
CWE-59: Improper Link Resolution Before File Access ('Link Following')
The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.
How to prevent it
- Architecture and Design: Follow the principle of least privilege when assigning access rights to entities in a software system. Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.
References
Advisories
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-fmxq-cgp8-87wp Argo CD: AppProject destination-namespace and resource restrictions bypassed by PreDelete/PostDelete resource hooks | Critical | Also affects github.com/argoproj/argo-cd |
| GHSA-j6cw-g6p4-7hch Argo CD repo-server command injection via crafted SSH repository SOCKS5 proxy URL | High | Also affects github.com/argoproj/argo-cd |
| GHSA-h98r-wv3h-fr38 Argo CD: Stored XSS in application link annotations enables developer-to-admin privilege escalation | High | Also affects github.com/argoproj/argo-cd |
| GO-2026-5618 Argo CD: Kubernetes Secret Extraction via ArgoCD ServerSideDiff via sensitive annotations | Medium | Also affects github.com/argoproj/argo-cd |
| GO-2026-5099 ArgoCD ServerSideDiff is vulnerable to Kubernetes Secret Extraction | Critical | Also affects github.com/argoproj/argo-cd |
| GHSA-gpx4-37g2-c8pv Argo CD Unauthenticated Remote DoS via malformed Azure DevOps git.push webhook | High | Also affects github.com/argoproj/argo-cd |
| GHSA-wp4p-9pxh-cgx2 argo-cd vulnerable unauthenticated DoS via malformed Gogs webhook payload | High | Also affects github.com/argoproj/argo-cd |
| GHSA-f9gq-prrc-hrhc Unauthenticated argocd-server panic via a malicious Bitbucket-Server webhook payload | High | Also affects github.com/argoproj/argo-cd |
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