CVE-2024-52308

The GitHub CLI version 2.6.1 and earlier are vulnerable to remote code execution through a malicious codespace SSH server when using gh codespace ssh or gh codespace logs commands. This has been patched in the cli v2.62.0.

Developers connect to remote codespaces through an SSH server running within the devcontainer, which is generally provided through the [default devcontainer image]( https://docs.github.com/en/codespaces/setting-up-your-project-for-codespaces/adding-a-dev-container-… https://docs.github.com/en/codespaces/setting-up-your-project-for-codespaces/adding-a-dev-container-configuration/introduction-to-dev-containers#using-the-default-dev-container-configuration) . GitHub CLI [retrieves SSH connection details]( https://github.com/cli/cli/blob/30066b0042d0c5928d959e288144300cb28196c9/internal/codespaces/rpc/inv… https://github.com/cli/cli/blob/30066b0042d0c5928d959e288144300cb28196c9/internal/codespaces/rpc/invoker.go#L230-L244 ), such as remote username, which is used in [executing ssh commands]( https://github.com/cli/cli/blob/e356c69a6f0125cfaac782c35acf77314f18908d/pkg/cmd/codespace/ssh.go#L2… https://github.com/cli/cli/blob/e356c69a6f0125cfaac782c35acf77314f18908d/pkg/cmd/codespace/ssh.go#L263 ) for gh codespace ssh or gh codespace logs commands.

This exploit occurs when a malicious third-party devcontainer contains a modified SSH server that injects ssh arguments within the SSH connection details. gh codespace ssh and gh codespace logs commands could execute arbitrary code on the users workstation if the remote username contains something like -oProxyCommand=echo hacked #. The -oProxyCommand flag causes ssh to execute the provided command while # shell comment causes any other ssh arguments to be ignored.

In 2.62.0, the remote username information is being validated before being used.

Weakness

The product constructs all or part of a command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended command when it is sent to a downstream component.

Affected Software

Extended Description

Command injection vulnerabilities typically occur when:

Many protocols and products have their own custom command language. While OS or shell command strings are frequently discovered and targeted, developers may not realize that these other command languages might also be vulnerable to attacks. Command injection is a common problem with wrapper programs.

Potential Mitigations

• 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.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/136.html
• https://cwe.mitre.org/data/definitions/15.html
• https://cwe.mitre.org/data/definitions/183.html
• https://cwe.mitre.org/data/definitions/248.html
• https://cwe.mitre.org/data/definitions/40.html
• https://cwe.mitre.org/data/definitions/43.html
• https://cwe.mitre.org/data/definitions/75.html
• https://cwe.mitre.org/data/definitions/76.html

References

• https://github.com/cli/cli/security/advisories/GHSA-p2h2-3vg9-4p87