1. Web Security Academy
  2. XXE injection
  3. Blind
  4. Lab

Lab: Exploiting XXE to retrieve data by repurposing a local DTD

EXPERT

This lab has a "Check stock" feature that parses XML input but does not display the result.

To solve the lab, trigger an error message containing the contents of the /etc/passwd file.

You'll need to reference an existing DTD file on the server and redefine an entity from it.

Hint

Systems using the GNOME desktop environment often have a DTD at /usr/share/yelp/dtd/docbookx.dtd containing an entity called ISOamso.

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