fix(apps): prevent open redirect via backslash manipulation in Host header#3740
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This pull request introduces a domain validation helper function isValidDomain to sanitize the hostname in the DNS redirecting function, returning a 400 error for invalid hostnames. Feedback suggests improving this helper by adding runtime type safety checks and escaping the hyphen in the regular expression to prevent potential bypasses and ensure regex maintainability.
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alan-agius4
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This PR fixes an Open Redirect vulnerability in the
dns-redirectingCloud Function. The fix implements strict hostname validation (isValidDomain) to ensure only alphanumeric characters, dots, and hyphens are allowed, securely preventing attackers from bypassing subdomain verification via backslashes.\n\nValidated that tests pass and the bypass viaevil.com\\.material.angular.iois appropriately rejected with a 400 Bad Request.