Security research, field notes, and practical experiments

Writing

Independent technical notes by Willis Vandevanter, published in reverse chronological order.

Recent writing

  1. Exploiting GraphQL Secondary Context Attacks

    Misconfigured GraphQL implementations can allow for attackers to bypass authorization and access internal APIs. These “secondary context attacks” exploit the gap between GraphQL’s frontend interface and backend REST services, often turning simple path …

  2. odle ruby gem: piping security data

    I recently (May 2018) published odle which is a Ruby gem and binary that takes XML data from various security tools and outputs their JSON equivalent. The goal is to be (1) simple, (2) fast, and (3) work on many platforms with only one dependency – nokogiri. …

  3. Exploiting CVE-2016-4264 With OXML_XXE

    Recently ColdFusion was shown vulnerable to XXE based attacks in OXML documents; CVE-2016-4264. The blog post linked gives an example building the file using python; cool! It’s easy to backdoor files in a similar fashion with OXML XXE. The fastest way to do …

  4. Exploiting XXE In File Upload Functionality

    Just wanted to post some details from my BH USA 2015 briefing “Exploiting XXE In File Upload Functionality”. https://www.youtube.com/watch?v=LZUlw8hHp44 I also gave an updated version of the presentation in November for the Blackhat Webcast Series. It included …