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Technical writeups

Readable previews before the full technical blog.

Short summaries help reviewers understand the method quickly, then jump into the full writeup when needed.

Full detailed writeups with syntax highlighting are available on the dedicated blog → Chirpy blog for longer notes, code blocks, categories and tags.

Writeup index

Five technical notes, sorted by date.

This portfolio page keeps the summaries short. The dedicated blog carries the long-form versions with categories, tags and syntax highlighting.

CTF / Team GHOSTSHELL

CSIA CTF 2026 first-place writeups

29 April 2026

Collection of CSIA CTF 2026 solutions covering web exploitation, forensics, reverse engineering, steganography, misc decoding and OSINT. The key techniques included JWT alg=none abuse, prototype pollution, Apache 2.4.49 traversal and RCE, LSB extraction with zsteg, signal decoding from JSON and social-archive pivots. Tools included curl, ffuf, Python, zsteg, grep and browser source inspection. The notes show how the team converted small clues into reproducible solve paths.

1st placeWebStegoOSINT

ENSET Challenge 2026 / Pwn

Browzi MiniBrowser heap exploitation

20 April 2026

Pwn challenge based on a minimal browser engine that parsed HTML into heap-allocated Node and RenderOps structures. The vulnerability was an unchecked img src copy into data[128], allowing an adjacent function pointer to be overwritten. GDB was used to map the heap layout, calculate the 144-byte offset and validate the partial overwrite constraint. pwntools completed the exploit by leaking render_div, computing win and overwriting ops->render with a 6-byte pointer.

PwnHeapGDBpwntools

CITEFLAG Qualifiers 2026 / Web

deepwash PHP DateTime parser logic

15 March 2026

Web challenge built around PHP DateTimeImmutable::createFromFormat and strict hash checks over parsed values. The weakness was silent date normalization: invalid days, day-of-year overflow and hour overflow were accepted and normalized instead of rejected. The solution used source review, PHP parser behavior and curl to construct a three-line payload that satisfied md5 and sha256 constraints. The writeup demonstrates why parser edge cases matter when validation depends on formatted output.

WebPHPParser logic

Academia Cyber / Active Directory

SOKOLO AD lab attack chain

1 February 2026

Active Directory lab progress note following an attack chain from provided user credentials to workstation administrator access. The work covered RDP access, SMB enumeration, SAM hash extraction, pass-the-hash with Impacket, DPAPI credential discovery, BloodHound review and Kerberos ticket attempts. The main techniques were local privilege pivoting, machine-account analysis and Resource-Based Constrained Delegation reasoning. The note documents both successful steps and the Kerberos/SPN issues that still needed correction.

Active DirectoryBloodHoundImpacket

Dedicated blog

All long-form notes

Chirpy / Categories / Tags

The full blog is the best place for longer reading, syntax highlighting and archive navigation. This portfolio page stays as the quick review layer for recruiters and technical reviewers.

syntaxtagsarchives

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