Hey I’m Jesus

Appsec, Bugbounty and hacking related stuff.

From Redirect to Merchant Administration Takeover at a Major Bank

Disclaimer This blog post is shared for educational and academic purposes only. All issues described here were responsibly reported to the affected company and have since been verified. The intention of this write-up is to raise awareness, improve security practices, and share lessons learned with the community. Since I was back in Korea and looking for my next role, I decided to spend this month fully focused on bug bounties again. It’s always a mix of frustration and small breakthroughs. One of the simple but surprisingly interesting bugs I uncovered was this cross-domain redirect flaw in a bank’s merchant administration flow. ...

February 22, 2026 · 5 min · 982 words · Jesus Lujan

Tickets and Popcorn please!, The Day main.js Became the Key Vault

Disclaimer This blog post is shared for educational and academic purposes only. All issues described here were responsibly reported to the affected company and have since been fixed and verified. Permission to publish was granted by the company. The intention of this write-up is to raise awareness, improve security practices, and share lessons learned with the community. Act I — The Setup It all started on a lazy evening in April. I wasn’t trying to hack anything major, just poking around a movie ticketing site which I’m client of with DevTools open. As I added a ticket to my cart, something odd caught my eye: a POST request carrying a mysterious parameter named encInfo. ...

August 25, 2025 · 7 min · 1431 words · Jesus Lujan

Cyber Apocalypse 2025 - 6x Web Challenges Writeup

I participated as a member of team CibersecUNI. This time i managed to solve all 6/6 challenges in the web category. Whispers of the Moonbeam Observando las funciones, nos dan una pista que se puede inyectar comandos con ;. Usando el comando gossip, puedo listar los archivos, se visualiza el archivo flag.txt, y con un simple ; puedo concatenar el comando cat para leer la flag. gossip; cat flag.txt Obtenemos la flag. 🎉 HTB{Sh4d0w_3x3cut10n_1n_Th3_M00nb34m_T4v3rn_78cb9b70be3bf077e608865b967b5ab1} ...

March 25, 2025 · 6 min · 1230 words · Jesus Lujan

Cyber Apocalypse 2024 - 4x Web Challenges Writeup

I participated as a member of team CibersecUNI. In the web category we solved 6/9 challenges as a team. In this writeup I will go through the ones that I have solved: Testimonial Labyrinth Linguist TimeKORP Locktalk Testimonial As the leader of the Revivalists you are determined to take down the KORP, you and the best of your faction’s hackers have set out to deface the official KORP website to send them a message that the revolution is closing in. ...

March 14, 2024 · 9 min · 1891 words · Jesus Lujan

Web Cache Poisoning Techniques

Web cache Poisoning Web cache poisoning is not web cache deception, is not response splitting or request smuggling web cache deception tricking caches into storing sensitive information so the attackers can access to it. web cache poisoning is serve payloads to users via cache responses Cache keys: The unique identifier that the server wont cache (refresh based on that: only host + path) “Everything that is not part of the cache key is part of the cache poisoning attack surface” ...

February 10, 2024 · 11 min · 2195 words · Jesus Lujan