Fix shell injection vulnerability in GitHub Actions workflow#20
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Fix shell injection vulnerability in GitHub Actions workflow#20semgrep-code-studentsca023-rgb[bot] wants to merge 1 commit into
semgrep-code-studentsca023-rgb[bot] wants to merge 1 commit into
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Fix command injection vulnerability by moving GitHub context data to an environment variable.
## Changes
- Moved `${{ github.head_ref }}` from inline interpolation in the `run:` script to an environment variable `BRANCH_NAME` in the `env:` block
- Referenced the branch name using double-quoted environment variable `"$BRANCH_NAME"` to prevent shell expansion issues
## Why
Direct interpolation of `${{ github.head_ref }}` in a `run:` step is vulnerable to command injection. An attacker could create a pull request from a branch with a malicious name containing shell metacharacters, which would be executed by the runner. By passing the value through an environment variable instead, the data is properly escaped and cannot break out of the intended context.
## Semgrep Finding Details
Using variable interpolation `${{...}}` with `github` context data in a `run:` step could allow an attacker to inject their own code into the runner. This would allow them to steal secrets and code. `github` context data can have arbitrary user input and should be treated as untrusted. Instead, use an intermediate environment variable with `env:` to store the data and use the environment variable in the `run:` script. Be sure to use double-quotes the environment variable, like this: "$ENVVAR".
@267212124 requested Semgrep Assistant generate this pull request to fix [a finding](https://semgrep.dev/orgs/studentsca023_personal_org/findings/722169002) from the detection rule [yaml.github-actions.security.run-shell-injection.run-shell-injection](https://semgrep.dev/r/yaml.github-actions.security.run-shell-injection.run-shell-injection).
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Fix command injection vulnerability by moving GitHub context data to an environment variable.
Changes
${{ github.head_ref }}from inline interpolation in therun:script to an environment variableBRANCH_NAMEin theenv:block"$BRANCH_NAME"to prevent shell expansion issuesWhy
Direct interpolation of
${{ github.head_ref }}in arun:step is vulnerable to command injection. An attacker could create a pull request from a branch with a malicious name containing shell metacharacters, which would be executed by the runner. By passing the value through an environment variable instead, the data is properly escaped and cannot break out of the intended context.Semgrep Finding Details
Using variable interpolation
${{...}}withgithubcontext data in arun:step could allow an attacker to inject their own code into the runner. This would allow them to steal secrets and code.githubcontext data can have arbitrary user input and should be treated as untrusted. Instead, use an intermediate environment variable withenv:to store the data and use the environment variable in therun:script. Be sure to use double-quotes the environment variable, like this: "$ENVVAR".@267212124 requested Semgrep Assistant generate this pull request to fix a finding from the detection rule yaml.github-actions.security.run-shell-injection.run-shell-injection.