Fix shell injection vulnerability in GitHub Actions workflow#21
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Fix command injection vulnerability by using an environment variable instead of direct interpolation of `github.head_ref` in the workflow run step.
## Changes
- Added `BRANCH_NAME` environment variable to store `github.head_ref`
- Replaced direct `${{ github.head_ref }}` interpolation with double-quoted `"$BRANCH_NAME"` in the run script
## Why
Direct interpolation of GitHub context data (like `github.head_ref`) in a `run:` step is vulnerable to command injection. An attacker could create a branch with a malicious name containing shell metacharacters to execute arbitrary commands in the runner, potentially stealing secrets and code.
By using an intermediate environment variable and double-quoting it, the value is treated as a literal string rather than being parsed by the shell, preventing injection attacks.
## 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 using an environment variable instead of direct interpolation of
github.head_refin the workflow run step.Changes
BRANCH_NAMEenvironment variable to storegithub.head_ref${{ github.head_ref }}interpolation with double-quoted"$BRANCH_NAME"in the run scriptWhy
Direct interpolation of GitHub context data (like
github.head_ref) in arun:step is vulnerable to command injection. An attacker could create a branch with a malicious name containing shell metacharacters to execute arbitrary commands in the runner, potentially stealing secrets and code.By using an intermediate environment variable and double-quoting it, the value is treated as a literal string rather than being parsed by the shell, preventing injection attacks.
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.