Evil GIFs: Partial Same Origin Bypass with Hybrid Files. First there were PNGs that had crossdomain.xml files embedded in them, now there are GIFs that contain Java applets (as JAR files). At this point I’d say don’t even bother trying to validate uploaded files, just make sure they’re served off an entirely different domain instead where XSS doesn’t matter.
Recent articles
- Video: Building a tool to copy-paste share terminal sessions using Claude Code for web - 23rd October 2025
- Dane Stuckey (OpenAI CISO) on prompt injection risks for ChatGPT Atlas - 22nd October 2025
- Living dangerously with Claude - 22nd October 2025