CEH Web Application and Injection Attacks Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  SQL injection

  Why it's wrong here

  SQL injection exploits vulnerabilities in database queries, typically through user input manipulating SQL statements. XXE, however, targets the XML parser's handling of external entities, operating on a different application layer entirely. While both are injection flaws, their attack vectors and affected components are distinct, meaning XXE does not directly translate into SQL injection.

• ✓

  Arbitrary file read on the server

  Why this is correct

  XXE vulnerabilities allow an attacker to define external entities that reference local files on the server using the `file://` URI scheme. When the XML parser processes this entity, it attempts to retrieve the content of the specified file, such as `/etc/passwd` or application configuration files. This content is then embedded into the XML response, enabling the attacker to read sensitive system files.

• ✓

  Denial of Service (DoS)

  Why this is correct

  A Denial of Service (DoS) attack via XXE often leverages XML bombs, such as the 'billion laughs' attack, which exploit recursive entity expansion. By defining nested entities that repeatedly reference each other, the XML parser consumes an exponential amount of memory and CPU resources. This rapid resource exhaustion can quickly crash the application or the underlying server, rendering the service unavailable to legitimate users.

• ✓

  Server-Side Request Forgery (SSRF)

  Why this is correct

  Server-Side Request Forgery (SSRF) can be achieved through XXE by defining external entities that instruct the vulnerable XML parser to make HTTP or Gopher requests to arbitrary URLs. This allows an attacker to force the server to connect to internal network resources, cloud metadata APIs, or other services that are not directly exposed to the internet. The server then acts as a proxy, potentially revealing sensitive internal information or interacting with internal services on the attacker's behalf.

• ✗

  Remote code execution via command injection

  Why it's wrong here

  Remote Code Execution (RCE) via command injection is not a direct consequence of an XXE vulnerability itself, as XXE primarily involves XML parsing and entity resolution, not direct operating system command execution. While XXE can be a crucial step in a multi-stage attack chain (e.g., by reading configuration files that expose credentials, or facilitating SSRF to exploit an internal service that *does* allow RCE), it does not inherently provide the capability to inject and execute arbitrary system commands.

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