Ctf Malware

What it does

When your agent uses it

• Analyzing obfuscated scripts
• Malicious packages
• Custom crypto protocols
• PE/.NET binaries

Example prompts

• “Use the ctf-malware skill to provide malware analysis and network traffic techniques for CTF challenges”
• “/ctf-malware”

Requirements

• Python 3
• Compatibility (from SKILL.md): Requires filesystem-based agent (Claude Code or similar) with bash, Python 3, and internet access for tool installation.
• Pre-approved tools (allowed-tools): Bash, Read, Write, Edit, Glob, Grep, Task, WebFetch, WebSearch

What it can do on your machine

Read from SKILL.md and the folder at commit c332c7b. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves these tools, so the agent can use them without asking each time:

  • Bash
  • Read
  • Write
  • Edit
  • Glob
  • Grep
  • Task
  • WebFetch
  • WebSearch

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  Shell commands in SKILL.md call:

  • pip
  • apt
  • brew
  • python3

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  Links to these hosts (documentation or services it may open):

  • github.com

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

• Compatibility

  Requires filesystem-based agent (Claude Code or similar) with bash, Python 3, and internet access for tool installation.

  From compatibility in the SKILL.md frontmatter.

Context cost

Ctf Malware loads about 2.1k tokens when it runs. Until then it costs about 133 tokens; SKILL.md has 630 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~133

When it runs · the whole SKILL.md, loaded when a task matches

~2.1k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

• NotePre-approves every shell command (allowed-tools: Bash)SKILL.md

  allowed-tools: Bash, Read, Write, Edit, Glob, Grep, Task, WebFetch, WebSearch

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from ljagiello/ctf-skills at commit c332c7b, republished under its MIT licence (© ljagiello). 630 words, ~2,098 tokens.

name

ctf-malware

description

Provides malware analysis and network traffic techniques for CTF challenges. Use when analyzing obfuscated scripts, malicious packages, custom crypto protocols, C2 traffic, PE/.NET binaries, RC4/AES encrypted communications, YARA rules, shellcode analysis, memory forensics for malware (Volatility malfind, process injection detection), anti-analysis techniques (VM/sandbox detection, timing evasion, API hashing, process injection, environment checks), or extracting malware configurations and indicators of compromise.

allowed-tools

Bash, Read, Write, Edit, Glob, Grep, Task, WebFetch, WebSearch

compatibility

Requires filesystem-based agent (Claude Code or similar) with bash, Python 3, and internet access for tool installation.

license

MIT

metadata.user-invocable

false

pip install yara-python pefile capstone oletools unicorn pycryptodome \
  volatility3 dissect.cobaltstrike

apt install strace ltrace tshark binwalk binutils

brew install wireshark binwalk binutils ghidra

# Static analysis
file suspicious_file
strings -n 8 suspicious_file | head -50
xxd suspicious_file | head -20

# PE analysis
python3 -c "import pefile; pe=pefile.PE('mal.exe'); print(pe.dump_info())" | head
peframe mal.exe

# Dynamic analysis (sandboxed!)
strace -f -s 200 ./suspicious 2>&1 | head -100
ltrace ./suspicious 2>&1 | head -50

# Network indicators
strings suspicious_file | grep -E '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}'
strings suspicious_file | grep -iE 'http|ftp|ws://'

# YARA scan
yara -r rules.yar suspicious_file

tshark -r file.pcap -Y "tcp.stream eq X" -T fields -e tcp.payload

peframe malware.exe      # Quick triage
pe-sieve                 # Runtime analysis
pestudio                 # Static analysis (Windows)

ar -x package.deb && tar -xf control.tar.xz  # Check postinst scripts

strings malware | grep -E '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}'
tshark -r capture.pcap -Y "dns.qry.name" -T fields -e dns.qry.name | sort -u

© ljagiello, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 3 other files in ctf-malware of ljagiello/ctf-skills.

• SKILL.md
• c2-and-protocols.md
• pe-and-dotnet.md
• scripts-and-obfuscation.md

Open the folder on GitHubat commit c332c7b