crwnctl

Writeups

CTF Solutions & Case Studies

Technical walkthroughs of cybersecurity challenges, featuring reconnaissance, exploitation techniques, reasoning, and lessons learned.

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picoCTF 2026 Writeups

A curated collection of detailed writeups from picoCTF 2026, with additional challenges being added over time.

May 2026

Binary Digits

A .bin file containing only ones and zeros hides a flag image. Solved by piping the binary data through CyberChef's From Binary → Render Image recipe.

picoCTFForensicsCyberChefBinary
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May 2026

Password Profiler

Used CUPP to generate a targeted wordlist from provided user info, then ran it against a SHA-1 hash checker script to crack the password and retrieve the flag.

picoCTFGeneral SkillsCUPPPassword Cracking
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Apr 2026

Shared Secrets

Asymmetric encryption challenge with the private key provided. Adapted the encryption script to decrypt by swapping inputs and substituting real keys.

picoCTFCryptographyPythonAsymmetric
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Apr 2026

StegoRSA

RSA private key hidden in JPEG metadata as a hex comment. Extracted with ExifTool, decoded in CyberChef, then used OpenSSL to decrypt the flag file.

picoCTFCryptographyRSASteganographyExifTool
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Apr 2026

Quizploit

Quiz-style binary analysis covering ELF inspection, checksec protections, stack overflow identification, and locating the win() function address via objdump.

picoCTFBinary ExploitationchecksecobjdumpELF
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Apr 2026

Sudo Make Me A Sandwich

SSH access with sudo rights to run emacs as root. Escalated privileges by spawning a shell through emacs eval to read the flag.

picoCTFGeneral SkillsPrivilege Escalationsudoemacs
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Apr 2026

Piece by Piece

Reconstructed a split zip archive from file fragments using cat, then extracted with the provided password to reveal the flag.

picoCTFGeneral SkillsLinuxFile SplittingZip
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Apr 2026

Bytemancy-0

Prompt asks for ASCII decimal 101 repeated side-by-side. Walkthrough covers why the check maps to 'eee' and how to solve quickly from source inspection.

picoCTFGeneral SkillsASCII
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Apr 2026

Bytemancy-1

Byte-conjuring variant where user input must match \x65 repeated 1751 times. Covers translating the condition into the exact required payload.

picoCTFGeneral SkillsScripting
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Apr 2026

Printer Shares

SMB share enumeration using smbclient to locate exposed printer-share artifacts and recover the challenge file from a misconfigured network share.

picoCTFNetworkingSMBEnumeration
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Apr 2026

My Git

Git-focused challenge: inspect repository contents, follow README instructions, and use basic Git/file operations to recover the flag.

picoCTFGeneral SkillsGit
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