fix open redirect vulnerability in OAuth callback handler#265
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fix open redirect vulnerability in OAuth callback handler#265semgrep-code-rootflo[bot] wants to merge 1 commit intodevelopfrom
semgrep-code-rootflo[bot] wants to merge 1 commit intodevelopfrom
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Add URL validation to prevent open redirect attacks in the OAuth callback flow. ## Changes - Added `validate_redirect_url()` function to `user_utils.py` that validates redirect URLs by: - Ensuring only `http`/`https` schemes are allowed - Requiring a valid host (netloc) - Blocking protocol-relative URL bypasses (e.g., `//evil.com`) - Blocking backslash-based bypasses (e.g., `/\evil.com`) - Blocking URLs with embedded credentials (e.g., `https://attacker@victim.com`) - Supporting optional domain allowlist validation - Updated `auth_plugin_controller.py` to validate `success_url` and `failure_url` before using them in `RedirectResponse` - Invalid URLs now fall back to `about:blank` instead of redirecting to potentially malicious domains ## Why The `client_redirect_success_url` and `client_redirect_failure_url` values from configuration were being used directly in `RedirectResponse` without validation. An attacker who could control these configuration values could redirect users to malicious domains, enabling phishing attacks or credential theft. The new validation ensures all redirect URLs are safe before use. ## Semgrep Finding Details The application builds a URL using user-controlled input which can lead to an open redirect vulnerability. An attacker can manipulate the URL and redirect users to an arbitrary domain. Open redirect vulnerabilities can lead to issues such as Cross-site scripting (XSS) or redirecting to a malicious domain for activities such as phishing to capture users' credentials. To prevent this vulnerability perform strict input validation of the domain against an allowlist of approved domains. Notify a user in your application that they are leaving the website. Display a domain where they are redirected to the user. A user can then either accept or deny the redirect to an untrusted site. @18578539 requested Semgrep Assistant generate this pull request to fix [a finding](https://semgrep.dev/orgs/rootflo_ai/findings/683091413) from the detection rule [python.fastapi.web.tainted-redirect-fastapi.tainted-redirect-fastapi](https://semgrep.dev/r/python.fastapi.web.tainted-redirect-fastapi.tainted-redirect-fastapi).
![github-code-quality[bot]](https://avatars.githubusercontent.com/u/9919?s=60&v=4){kind=small}
| ) | ||
| return RedirectResponse(url=f'{failure_url}?{params}') | ||
| except Exception as e: | ||
| except Exception: |
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Add URL validation to prevent open redirect attacks in the OAuth callback flow.
Changes
validate_redirect_url()function touser_utils.pythat validates redirect URLs by:http/httpsschemes are allowed//evil.com)/\evil.com)https://attacker@victim.com)auth_plugin_controller.pyto validatesuccess_urlandfailure_urlbefore using them inRedirectResponseabout:blankinstead of redirecting to potentially malicious domainsWhy
The
client_redirect_success_urlandclient_redirect_failure_urlvalues from configuration were being used directly inRedirectResponsewithout validation. An attacker who could control these configuration values could redirect users to malicious domains, enabling phishing attacks or credential theft. The new validation ensures all redirect URLs are safe before use.Semgrep Finding Details
The application builds a URL using user-controlled input which can lead to an open redirect vulnerability. An attacker can manipulate the URL and redirect users to an arbitrary domain. Open redirect vulnerabilities can lead to issues such as Cross-site scripting (XSS) or redirecting to a malicious domain for activities such as phishing to capture users' credentials. To prevent this vulnerability perform strict input validation of the domain against an allowlist of approved domains. Notify a user in your application that they are leaving the website. Display a domain where they are redirected to the user. A user can then either accept or deny the redirect to an untrusted site.
@18578539 requested Semgrep Assistant generate this pull request to fix a finding from the detection rule python.fastapi.web.tainted-redirect-fastapi.tainted-redirect-fastapi.