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3 posts across writeups, research, and technical deep-dives. Filter by tag.

3 posts
2026.05.10
Bug BountyXSSDOM XSS

My First Bug Bounty: A DOM XSS

I found my first DOM-based XSS in a bug bounty program. No SQLi, no RCE - just a missing origin check in a postMessage listener and a javascript: URI. CVSS 9.0. Sink-to-source analysis, exploit chain, and some bonus impact.

9 min
2025.09.21
CTFWeb SecurityJWT

Amazon AppSec CTF: HalCrypto

CTF writeup: a JWT jku URL check uses lastIndexOf instead of real parsing, so an @ symbol tricks it into trusting an attacker-hosted JWKS and bypasses auth.

6 min
2025.09.21
CTFWeb SecuritySSRF

Amazon AppSec CTF: PageOneHTML

CTF writeup: an image-fetching helper on node-libcurl accepts any protocol, turning a markdown converter into an SSRF reaching an internal API via gopher://.

5 min
>_ esc