GHSA-vm62-9jw3-c8w3 CVE-2024-39930 GHSA-p69r-v3h4-rj4f GO-2024-2969
Gogs has an argument Injection in the built-in SSH server
Critical
Go
- Severity
- 0.0 / 10
- Critical · CVSS 4.0
- Exploit chance (EPSS)
- 7.74%
- Chance of exploitation in the next 30 days. Higher than 94.63% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-88 Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')
- Fix
0.13.1- Upgrade gogs.io/gogs to this version or later
Description
Impact
When the built-in SSH server is enabled ([server] START_SSH_SERVER = true), unprivileged user accounts with at least one SSH key can execute arbitrary commands on the Gogs instance with the privileges of the user specified by RUN_USER in the configuration. It allows attackers to access and alter any users' code hosted on the same instance.
Patches
The env command sent to the internal SSH server has been changed to be a passthrough (https://github.com/gogs/gogs/pull/7868), i.e. the feature is effectively removed. Users should upgrade to 0.13.1 or the latest 0.14.0+dev.
Workarounds
Disable the use of built-in SSH server on operating systems other than Windows.
References
Affected versions
Go
| Package | Vulnerable | Fixed in |
|---|---|---|
| github.com/gogs/gogs | <= 0.13.0 |
No fix yet |
| github.com/gogs/gogs | all versions |
No fix yet |
| gogs.io/gogs | < 0.13.1 |
0.13.1 |
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.
gogs.io/gogs Go → 0.13.1
- go
go get gogs.io/gogs@v0.13.1 && go mod tidy
Severity breakdown
CVSS 4.0 0.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- None
- Privileges required
- Low
- User interaction
- None
- Confidentiality (vulnerable system)
- High
- Integrity (vulnerable system)
- High
- Availability (vulnerable system)
- High
- Confidentiality (subsequent systems)
- High
- Integrity (subsequent systems)
- High
- Availability (subsequent systems)
- High
CVSS 3.1 9.9
CVSS:3.1/AC:L/AV:N/A:H/C:H/I:H/PR:L/S:C/UI:N
- Attack complexity
- Low
- Attack vector
- Network
- Availability
- High
- Confidentiality
- High
- Integrity
- High
- Privileges required
- Low
- Scope
- Changed
- User interaction
- None
Weakness
CWE-88: Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')
The product constructs a string for a command to be executed by a separate component in another control sphere, but it does not properly delimit the intended arguments, options, or switches within that command string.
How to prevent it
- Implementation: Where possible, avoid building a single string that contains the command and its arguments. Some languages or frameworks have functions that support specifying independent arguments, e.g. as an array, which is used to automatically perform the appropriate quoting or escaping while building the command. For example, in PHP, escapeshellarg() can be used to escape a single argument to system(), or exec() can be called with an array of arguments. In C, code can often be refactored from using system() - which accepts a single string - to using exec(), which requires separate function arguments for each parameter.
- Architecture and Design: Understand all the potential areas where untrusted inputs can enter your product: parameters or arguments, cookies, anything read from the network, environment variables, request headers as well as content, URL components, e-mail, files, databases, and any external systems that provide data to the application. Perform input validation at well-defined interfaces.
- 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.
- 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.
- 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.
- Testing: Use dynamic tools and techniques that interact with the product using large test suites with many diverse inputs, such as fuzz testing (fuzzing), robustness testing, and fault injection. The product's operation may slow down, but it should not become unstable, crash, or generate incorrect results.
References
Advisories
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-mq8m-42gh-wq7r Gogs vulnerable to a bypass of CVE-2024-55947 | High Known exploited | Also affects gogs.io/gogs |
| GHSA-3w28-36p9-w929 Gogs's Unauthenticated Jupyter Notebook (ipynb) Sanitizer allows arbitrary data: URIs leading to XSS | Medium | Also affects gogs.io/gogs |
| GHSA-744x-3838-5r56 Gogs Vulnerable to Unauthenticated Organization Teams Information Disclosure via API | Medium | Also affects gogs.io/gogs |
| GHSA-xp79-5mx3-jx52 Gogs has Unauthenticated Asymmetric Denial of Service (DoS) via SSH Handshake Stall (File Descriptor Exhaustion) | Medium | Also affects gogs.io/gogs |
| GHSA-c39w-43gm-34h5 Gogs has Path Traversal in organization name that results in RCE through Git hooks | Critical | Also affects gogs.io/gogs |
| GHSA-6p9m-q3jp-47h4 Gogs: LFS dedupe path leaks private repo content across tenants | High | Also affects gogs.io/gogs |
| GHSA-89mr-xqfv-758m Gogs: UploadRepoFiles writes outside repo working tree via committed parent sym | Critical | Also affects gogs.io/gogs |
| GHSA-wmfg-5p4h-5fw3 Gogs allows users to write to readonly repositories using receive-pack + service=git-upload-pack confusion | High | Also affects gogs.io/gogs |
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