CVE-2021-32638 is a vulnerability in github Codeql Action
Published on May 25, 2021
CodeQL runner: Command-line options that make GitHub access tokens visible to other processes are now deprecated
Github's CodeQL action is provided to run CodeQL-based code scanning on non-GitHub CI/CD systems and requires a GitHub access token to connect to a GitHub repository. The runner and its documentation previously suggested passing the GitHub token as a command-line parameter to the process instead of reading it from a file, standard input, or an environment variable. This approach made the token visible to other processes on the same machine, for example in the output of the `ps` command. If the CI system publicly exposes the output of `ps`, for example by logging the output, then the GitHub access token can be exposed beyond the scope intended. Users of the CodeQL runner on 3rd-party systems, who are passing a GitHub token via the `--github-auth` flag, are affected. This applies to both GitHub.com and GitHub Enterprise users. Users of the CodeQL Action on GitHub Actions are not affected. The `--github-auth` flag is now considered insecure and deprecated. The undocumented `--external-repository-token` flag has been removed. To securely provide a GitHub access token to the CodeQL runner, users should **do one of the following instead**: Use the `--github-auth-stdin` flag and pass the token on the command line via standard input OR set the `GITHUB_TOKEN` environment variable to contain the token, then call the command without passing in the token. The old flag remains present for backwards compatibility with existing workflows. If the user tries to specify an access token using the `--github-auth` flag, there is a deprecation warning printed to the terminal that directs the user to one of the above options. All CodeQL runner releases codeql-bundle-20210304 onwards contain the patches. We recommend updating to a recent version of the CodeQL runner, storing a token in your CI system's secret storage mechanism, and passing the token to the CodeQL runner using `--github-auth-stdin` or the `GITHUB_TOKEN` environment variable. If still using the old flag, ensure that process output, such as from `ps`, is not persisted in CI logs.
Vulnerability Analysis
CVE-2021-32638 is exploitable with local system access, and requires user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a high impact on confidentiality, with no impact on integrity and availability.
Weakness Types
What is an Information Disclosure Vulnerability?
The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
CVE-2021-32638 has been classified to as an Information Disclosure vulnerability or weakness.
Invocation of Process Using Visible Sensitive Information
A process is invoked with sensitive command-line arguments, environment variables, or other elements that can be seen by other processes on the operating system. Many operating systems allow a user to list information about processes that are owned by other users. Other users could see information such as command line arguments or environment variable settings. When this data contains sensitive information such as credentials, it might allow other users to launch an attack against the software or related resources.
Products Associated with CVE-2021-32638
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Affected Versions
github codeql-action Version < codeql-bundle-20210304 is affected by CVE-2021-32638Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.