ctf-forensics

ctf-forensics is a skill for Claude Code from 26zl/cybersec-toolkit. It costs 71 tokens per session (1,271 once invoked), scanned A, original, MIT.

A guide to solving capture-the-flag, or CTF, digital forensics challenges using disk images, memory dumps, network captures, logs, and recovered files. It helps identify the input type and choose suitable analysis tools.

In plain words
What is it for?
Use it to inspect file signatures, analyze PCAP network captures, recover carved files, examine memory images, and decode artifacts such as USB keyboard input.
Why use it?
It gives a repeatable way to extract useful evidence from unfamiliar files and traffic captures. This reduces guesswork when looking for hidden or deleted information.

Skill for Claude Code

Written for Claude Code: installed under .claude/.

Part of the cybersec-toolkit plugin — 197 skills, 2 hooks, 1 MCP server shipped together

Good fit Use it to inspect file signatures, analyze PCAP network captures, recover carved files, examine memory images, and decode artifacts such as USB keyboard input.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/26zl/cybersec-toolkit/ctf-forensics
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add 26zl/cybersec-toolkit --skill ctf-forensics
Clone the repo
git clone --depth 1 https://github.com/26zl/cybersec-toolkit

Made for: Claude Code.

Or install cybersec-toolkit, the plugin that ships this one along with the rest of its 197 skills, 2 hooks, 1 MCP server.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for ctf-forensics

README.md
[![agentmods](https://agentmods.dev/badge/skills/26zl/cybersec-toolkit/ctf-forensics/github.svg)](https://agentmods.dev/skills/26zl/cybersec-toolkit/ctf-forensics)
Your own site
<a href="https://agentmods.dev/skills/26zl/cybersec-toolkit/ctf-forensics"><img src="https://agentmods.dev/badge/skills/26zl/cybersec-toolkit/ctf-forensics/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for ctf-forensics

Your own site · 80×15
<a href="https://agentmods.dev/skills/26zl/cybersec-toolkit/ctf-forensics"><img src="https://agentmods.dev/badge/skills/26zl/cybersec-toolkit/ctf-forensics.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 71 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,271 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00071 $0.01271
Opus 5 $0.00036 $0.00635
Sonnet 5 $0.00014 $0.00254
Haiku 4.5 $0.00007 $0.00127

Measured 6d ago against content hash 809f9666bd40, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

ctf-forensics scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 6d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.claude/skills/ctf-forensics/SKILL.md · 136 lines

How it starts

The opening of the file, as written. The whole thing — 136 lines — stays where its author put it; the contents beside it link to each section on GitHub.

CTF forensics methodology

1. Identify the input

file <input>
xxd <input> | head -20
Magic Type First tool
7F 45 4C 46 ELF use ctf-rev skill
4D 5A PE use ctf-rev skill
PK ZIP/JAR/APK/Office unzip -l, binwalk
D4 C3 B2 A1 / 0A 0D 0D 0A PCAP / pcapng wireshark
4D 53 53 54 30 30 30 Volatility memory raw volatility
45 56 46 EWF / E01 image ewfmount
Arbitrary blob, high entropy Encrypted/compressed binwalk / strings

2. PCAP analysis

# Quick triage
capinfos <pcap>                                # summary
tshark -r <pcap> -q -z io,phs                  # protocol hierarchy
tshark -r <pcap> -q -z conv,tcp                # TCP conversations
tshark -r <pcap> -q -z http,tree               # HTTP requests

# Extract objects
tshark -r <pcap> --export-objects http,./out
foremost -i <pcap> -o ./carved

# Wireshark for visual: File → Export Objects → HTTP/SMB/etc

# Search payloads
tshark -r <pcap> -Y 'http.request.method == "POST"' -T fields -e http.file_data

USB HID keystroke decode (common challenge):

  • Filter usb.capdata in tshark
  • Map HID scancodes → keys (script: usbkeyboard.py, usbrip)

Bluetooth: btsnoop parser, wireshark natively decodes.

TLS with key log: tshark -r <pcap> -o tls.keylog_file:keys.log to decrypt.

3. Memory forensics (Volatility)

# Identify profile (vol2) or no profile needed (vol3)
vol.py -f mem.raw imageinfo                       # vol2
vol3 -f mem.raw windows.info                      # vol3

# Common plugins
vol3 -f mem.raw windows.pslist
vol3 -f mem.raw windows.cmdline
vol3 -f mem.raw windows.netstat
vol3 -f mem.raw windows.malfind
vol3 -f mem.raw windows.dumpfiles --pid <pid>
vol3 -f mem.raw windows.hashdump
vol3 -f mem.raw windows.lsadump
vol3 -f mem.raw windows.consoles                  # cmd.exe history
vol3 -f mem.raw windows.clipboard
vol3 -f mem.raw windows.registry.printkey -K "Software\Microsoft\Windows\CurrentVersion\Run"

# Linux
vol3 -f mem.raw linux.bash                        # bash history
vol3 -f mem.raw linux.psaux

Read the full file on GitHub · 136 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 6d ago First seen · 136 lines · 71 tokens per session scan A 809f9666bd40

Subscribe to this mod's changes

ctf-forensics is a skill published in the GitHub repository 26zl/cybersec-toolkit (52 stars, last pushed today), licensed MIT. It adds 71 tokens to every session and 1,271 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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