Belkahla Ahmed

Belkahla Ahmed

Product Security Engineer @ Mercari JP - CTF Player @ Zer0pts

Securinets

Biography

Cyber Security engineer from Tunisia, I enjoy playing in hacking and pentesting competitions and skip classes to play CTF.

Interests

  • Anime && Naruto
  • Cyber Security
  • Web & Mobile Exploitation
  • CTF
  • Pentesting
  • Coding
  • Football

Education

  • Engineers's Degree in Computer Science & Networks, 2023

    National Institute Of Applied Science And Technology, INSAT

Experience

 
 
 
 
 

Product Security Engineer

Mercari, Inc

Oct 2023 – Present
  • Application security and everything in between!
 
 
 
 
 

Product Security Engineer Intern

Mercari, Inc

Feb 2023 – May 2023
  • Internal security audits and CodeQL custom query development.
  • Mercari SSDLC Improvement.
 
 
 
 
 

Senior Penetration Tester

Electrovolt

Nov 2022 – Present
  • Web, Mobile & API penetration tests for global leaders.
 
 
 
 
 

Cybersecurity Consultant

EY

Jul 2022 – Feb 2023 Tunis, Tunisia
  • Conducting different red team operations and penetration testing missions for different clients from MENA and EMEA Regions
 
 
 
 
 

Cybersecurity Specialist

Yogosha

Sep 2021 – Jan 2023 Paris, France
  • Triaged and reproduced incoming vulnerability reports
  • Conducted web application penetration testing
  • Contributed to internal security projects and tools as needed
  • Managed the selection process for platform candidates, assessing technical and writing skills through CTF challenges
 
 
 
 
 

Cybersecurity Consultant

EY

May 2021 – Oct 2021 Tunis, Tunisia

Responsibilities include:

  • Participating in the development of EY CSIRT web platform.
  • Participating in several Pentest and vulnerability assessment missions for worldwide clients.
 
 
 
 
 

Cybersecurity Consultant & Penetration Tester [Part Time]

Defensylab

Oct 2020 – Mar 2021 Tunisia

Responsibilities include:

  • Directed several VAPT activities
  • Participating in SOCaaS solution development
  • Developing an automated Penetration Testing Framework
 
 
 
 
 

Vice Chair / Technical Manager

Securinets National Association

Jun 2019 – Present Tunisia

Responsibilities include:

  • Held Web Security Workshop throughout the semester
  • Held Networking Security Workshop
  • Held Active Directory Security & Attacks Workshop ( https://bit.ly/31MHMsj)
  • Organizing CTF challenges & CTF Infrastructure deployment
 
 
 
 
 

CTF Player

Fword & Zer0pts

Nov 2018 – Present
  • Where I started learning about Hacking & Cybersecurity
  • Web / Binary Exploitation technics
  • I learned more about Pentesting & Memory Forensics

Achievements

eWPTX v2 Certified

See certificate

CSAW MENA Finals 1st Place 2021

CSAW MENA Finals 2nd Place

See certificate

TT Security Day 3 CTF

3rd Place

Cybersecurity Fundamentals

See certificate

Recent Articles

Ringtone Web Challenge Writeup - Zer0pts CTF 2023

Zer0pts CTF took place last weekend with the participation of over 500 teams, making it a resounding success. As a member of the team, I contributed by developing a web challenge called “Ringtone,” which ended up being solved by 14 teams.

The Art of the Security Double Play: How Mercari Combines Internal Audits and Custom CodeQL Queries

How we seek to improve Security testing approach and use CodeQL to automate custom test cases

Securinets CTF Quals 2022 - Infrastructure and Web writeups

Securinets Quals 2022 Infrastructure review and Web challenges writeups.

PBCTF 2021 - RCE 0-Day in Goahead Webserver

2 methods RCE 0-Day in Goahead Webserver: PBCTF 2021 Last weekend I participated with my team Zer0pts in PBCTF 2021 and we got the 5th place, we were really close to secure a spot in the top 3 but an error in Wine while solving a shitty misc challenge prived us from this win :(

AngstromCTF Web Writeups

Finally after finishing my exams , I had the opportunity to participate in the last 2 days of AngstromCTF with my team Fword and managed to solve all the web challenges except the last 3 tasks, unfortunately I didn’t have the chance to try the last two ones , bad subjects at school are always keeping me from playing CTFs and learning useful stuffs :( !

Projects