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XXE

XML External Entity Injection is a web security vulnerability that allows an attacker to interfere with an application's processing of XML Data. It often allows an attacker to view files on the application server filesystem, and to interact with any back-end or external systems that the application itself can access.

In some situations, an attacker can escalate an XXE attack to compromise the underlying server or other back-end infrastructure, by leveraging the XXE vulnerability to perform server-side request forgery SSRF attacks.


  • There are Two Types of XXE:
    • In-Band: XXE Attack is the one in which the Attacker can receive an Immediate Response to the XXE Payload.
    • Out-Of-Band: XXE Attacks (Blind XXE), there is No Immediate Response from the Web Application and attacker has to reflect the output of their XXE payload to some other file or their own server.

XXE PAYLOAD​

<?xml version="1.0"?>
<!DOCTYPE root [<!ENTITY read SYSTEM 'file:///etc/passwd'>]>
<root>&read;</root>