CREST Practitioner Security Analyst (CPSA) Practice

In which scenario would you use XML External Entity (XXE) attacks?

1. To create XML documents

2. To manipulate user sessions

3. To gain access to confidential data

4. To distribute mail via SMTP

The correct answer is: To gain access to confidential data

Using XML External Entity (XXE) attacks primarily involves exploiting vulnerabilities in XML parsers to gain unauthorized access to confidential data. This type of attack occurs when the XML parser processes a malicious XML input that contains a reference to an external entity. By doing so, an attacker can access sensitive files on the server, read configuration files, or interact with other network services. In this scenario, the attacker takes advantage of poorly configured XML parsers that do not adequately validate input or limit the scope of the data they can access. When successful, an XXE attack can lead to exposure of sensitive information such as passwords, configuration settings, and personal data, potentially leading to further exploitation or data breaches. The other scenarios provided do not accurately represent the primary use of XXE attacks. Creating XML documents, manipulating user sessions, and distributing mail via SMTP do not utilize the specific vulnerabilities associated with XXE. They are separate processes that do not involve exploiting external entity definitions in XML, thus clarifying why gaining access to confidential data is the correct context for XXE attacks.