CTF Writeup Generator

Description

This skill helps CTF players, security researchers, and cybersecurity educators automatically generate professional writeups from their solving sessions. It intelligently detects flag formats, categorizes challenges, structures the writeup with proper headings, and includes code blocks with syntax highlighting. Perfect for: Creating platform-specific writeups (HackTheBox, TryHackMe, OffSec, etc.) Documenting Jeopardy-style CTF solutions Generating educational content for training materials Building a portfolio of security research

When to Use

Use this skill when the user: Says "generate a CTF writeup" Mentions "document my CTF solution" Asks to "create a writeup for [challenge name]" References completing a CTF challenge and needs documentation Wants to format their solving process professionally Needs to extract and format flags from their notes

Flag Format Detection

Automatically detects and validates common CTF flag formats: CTF{...}, FLAG{...}, flag{...} Platform-specific: HTB{...}, THM{...}, SHAASTRA{...}, picoCTF{...} Custom regex patterns for competition-specific formats Case-sensitive validation support

Challenge Categories

Automatically categorizes based on keywords and tools used: Web Exploitation: SQL injection, XSS, CSRF, authentication bypass Binary Exploitation: Buffer overflow, ROP, format strings, heap exploitation Reverse Engineering: Binary analysis, decompilation, obfuscation Cryptography: Classical ciphers, modern crypto, hash cracking Forensics: Steganography, memory forensics, network analysis, disk imaging OSINT: Information gathering, social media analysis PWN: Exploitation, shellcode, privilege escalation Miscellaneous: Mixed or unique challenge types

Structured Output

Generates properly formatted markdown writeups with: Challenge metadata (name, category, difficulty, points) Executive summary Reconnaissance findings Step-by-step solution with code blocks Tools used section Flag submission Key learnings and takeaways Optional: Additional resources and references

Code Formatting

Proper syntax highlighting for: Python, Bash, JavaScript, C/C++ Assembly (x86, ARM) SQL queries Command-line tools output Network packet analysis

Instructions

When a user requests a CTF writeup, follow this workflow: Gather Information Ask the user for: Challenge name Platform/CTF name (e.g., "HackTheBox", "Shaastra CTF") Category (or detect from description) Difficulty level (Easy/Medium/Hard or points value) Flag format if non-standard Their solving process/notes Process the Content Extract technical steps from their description Identify tools and commands used Detect flag format and validate Categorize the challenge Structure the flow logically Generate the Writeup Create a markdown document with this structure: # [Challenge Name] - [Platform] CTF Writeup **Author**: [Author name or handle] **Date**: [Current date] **Category**: [Category] **Difficulty**: [Difficulty] **Points**: [Points if applicable] ## Summary [2-3 sentence overview of the challenge and solution approach] ## Challenge Description [Original challenge description if provided] ## Reconnaissance [Initial enumeration and information gathering] ## Solution ### Step 1: [Phase name] [Detailed explanation with commands/code] ```bash # Commands used Step 2: [Next phase] [Continue with logical progression] Tools Used Tool 1: Purpose Tool 2: Purpose Flag FLAG{...} Key Takeaways Learning point 1 Learning point 2 References [Relevant links] Validate and Enhance Check flag format matches the platform Ensure code blocks have proper syntax highlighting Add explanatory comments to complex commands Include alternative approaches if mentioned Save the Writeup Save the generated writeup to a markdown file named: [platform]_[challenge-name]_writeup.md

Step 2: [Next phase]

[Continue with logical progression]

Tools Used

Tool 1: Purpose Tool 2: Purpose

Flag

FLAG{...}

Key Takeaways

Learning point 1 Learning point 2

References

[Relevant links]

Example Usage

User: "I just solved the 'Binary Bash' challenge from Shaastra CTF. It was a buffer overflow where I had to overwrite the return address. The flag was Shaastra{buff3r_0v3rfl0w_m4st3r}. Can you generate a writeup?" Agent Response: Asks for additional details (tools used, exact exploit steps) Generates a professional writeup with: Proper challenge metadata Binary exploitation category Step-by-step buffer overflow explanation Code blocks with assembly/C code GDB commands used Flag in correct format Learning points about memory safety

HackTheBox

Include machine IP, OS, and difficulty rating Add user/root flag sections Include attack path diagram if complex

OffSec/OSCP

Focus on enumeration methodology Document privilege escalation chains Include proof screenshots references

Jeopardy CTF

List point values and solve times Include team strategy if relevant Categorize by challenge type

Multi-Tool Integration

Reference other skills for specific tasks: ghidra-skill for reverse engineering analysis burpsuite-skill for web exploitation volatility-skill for memory forensics

Writeup Templates

Support for different writeup styles: Academic: Detailed with theoretical background Speedrun: Concise with just essential steps Tutorial: Beginner-friendly with extra explanations Portfolio: Professional format for job applications

Export Formats

Standard Markdown (.md) PDF via pandoc HTML with custom CSS Platform-specific formats (HTB Academy, Medium, dev.to)

Security Considerations

Never include actual credentials or sensitive API keys Sanitize paths that might reveal system information Respect competition rules (don't publish during active CTF) Add spoiler warnings for recent challenges Verify flag sharing is allowed by platform

Configuration

Users can customize via environment variables: # Set default author name export CTF_AUTHOR="akm626" # Set default CTF platform export CTF_PLATFORM="HackTheBox" # Set preferred writeup style export CTF_WRITEUP_STYLE="tutorial" # Enable automatic screenshot embedding export CTF_AUTO_SCREENSHOTS=true

Dependencies

Basic markdown processor (built-in) Optional: pandoc (for PDF export) Optional: pygments (for enhanced syntax highlighting)

Tips for Best Results

Provide detailed solving notes - the more context, the better Include command outputs when relevant Mention dead-ends and why they failed (valuable learning) Reference CVEs and tool documentation Add your unique insights and methodology Keep flag formats consistent with the platform

Example Writeup Structure

For a web exploitation challenge: # SQL Injection Master - Shaastra CTF 2026 **Author**: akm626 **Date**: February 08, 2026 **Category**: Web Exploitation **Difficulty**: Medium **Points**: 300 ## Summary This challenge involved exploiting a SQL injection vulnerability in a login form to extract database contents and retrieve the flag. The application used client-side filtering which was easily bypassed. ## Challenge Description [Original description...] ## Reconnaissance Initial enumeration revealed a PHP-based login portal running on Apache. Basic directory fuzzing found: ```bash ffuf -w common.txt -u http://target.com/FUZZ admin/ backup/ config/

Step 1: Identifying the Injection Point

Testing the login form with basic SQL injection payloads: ' OR '1'='1' -- admin' -- ' UNION SELECT NULL--

Step 2: Database Enumeration

Used SQLMap to automate extraction: sqlmap -u "http://target.com/login.php" --data="username=admin&password=test" \ --technique=U --dump --batch [Continue with detailed steps...]

Flag

SHAASTRA{sql_inj3ct10n_pr0}

Key Takeaways

Always test for SQL injection on input fields Client-side validation is not security Parameterized queries prevent SQL injection

Tools Used

Burp Suite: Request interception SQLMap: Automated SQL injection ffuf: Directory fuzzing

References

• OWASP SQL Injection Guide
• SQLMap Documentation
• ## Contributing
• Users can improve this skill by:
• Adding new flag format patterns
• Contributing platform-specific templates
• Enhancing categorization logic
• Sharing example writeups
• ## License
• MIT License - Free to use and modify
• ## Support
• For issues or suggestions, contact the skill maintainer or file an issue on the GitHub repository.