ctf-forensics

name	ctf-forensics
description	Digital forensics and blockchain analysis for CTF challenges. Use when analyzing disk images, memory dumps, event logs, network captures, cryptocurrency transactions, steganography, PDF analysis, Windows registry, Volatility, PCAP, Docker images, coredumps, or recovering deleted files and credentials.
license	MIT
compatibility	Requires filesystem-based agent (Claude Code or similar) with bash, Python 3, and internet access for tool installation.
allowed-tools	Bash Read Write Edit Glob Grep Task WebFetch WebSearch
metadata	{"user-invocable":"false"}

CTF Forensics & Blockchain

Quick reference for forensics CTF challenges. Each technique has a one-liner here; see supporting files for full details.

Additional Resources

• 3d-printing.md - 3D printing forensics (PrusaSlicer binary G-code, QOIF, heatshrink)
• windows.md - Windows forensics (registry, SAM, event logs, recycle bin, USN journal, PowerShell history, Defender MPLog, WMI persistence, Amcache)
• network.md - Network forensics (PCAP, SMB3, WordPress, credentials, NTLMv2 cracking, USB HID steno, BCD encoding, HTTP file upload exfiltration)
• disk-and-memory.md - Disk/memory forensics (Volatility, disk mounting/carving, VM/OVA/VMDK, coredumps, deleted partitions, ZFS, VMware snapshots, ransomware analysis, GPT GUID encoding, VMDK sparse parsing)
• steganography.md - Steganography (binary border stego, PDF multi-layer stego, FFT frequency domain, DTMF audio, SSTV+LSB, SVG keyframes, PNG reorder, file overlays)
• linux-forensics.md - Linux/app forensics (log analysis, Docker image forensics, attack chains, browser credentials, Firefox history, TFTP, TLS weak RSA, USB audio, Git directory recovery)
• signals-and-hardware.md - Hardware signal decoding with decode code (VGA frame parsing, HDMI TMDS symbol decode, DisplayPort 8b/10b + LFSR descrambler), Voyager Golden Record audio, Flipper Zero .sub files

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Quick Start Commands

# File analysis
file suspicious_file
exiftool suspicious_file     # Metadata
binwalk suspicious_file      # Embedded files
strings -n 8 suspicious_file
hexdump -C suspicious_file | head  # Check magic bytes

# Disk forensics
sudo mount -o loop,ro image.dd /mnt/evidence
fls -r image.dd              # List files
photorec image.dd            # Carve deleted files

# Memory forensics (Volatility 3)
vol3 -f memory.dmp windows.info
vol3 -f memory.dmp windows.pslist
vol3 -f memory.dmp windows.filescan

See disk-and-memory.md for full Volatility plugin reference, VM forensics, and coredump analysis.

Log Analysis

grep -iE "(flag|part|piece|fragment)" server.log     # Flag fragments
grep "FLAGPART" server.log | sed 's/.*FLAGPART: //' | uniq | tr -d '\n'  # Reconstruct
sort logfile.log | uniq -c | sort -rn | head         # Find anomalies

See linux-forensics.md for Linux attack chain analysis and Docker image forensics.

Windows Event Logs (.evtx)

Key Event IDs:

• 1001 - Bugcheck/reboot
• 1102 - Audit log cleared
• 4720 - User account created
• 4781 - Account renamed

RDP Session IDs (TerminalServices-LocalSessionManager):

• 21 - Session logon succeeded
• 24 - Session disconnected
• 1149 - RDP auth succeeded (RemoteConnectionManager, has source IP)

import Evtx.Evtx as evtx
with evtx.Evtx("Security.evtx") as log:
    for record in log.records():
        print(record.xml())

See windows.md for full event ID tables, registry analysis, SAM parsing, USN journal, and anti-forensics detection.

When Logs Are Cleared

If attacker cleared event logs, use these alternative sources:

1. USN Journal ($J) - File operations timeline (MFT ref, timestamps, reasons)
2. SAM registry - Account creation from key last_modified timestamps
3. PowerShell history - ConsoleHost_history.txt (USN DATA_EXTEND = command timing)
4. Defender MPLog - Separate log with threat detections and ASR events
5. Prefetch - Program execution evidence
6. User profile creation - First login time (profile dir in USN journal)

See windows.md for detailed parsing code and anti-forensics detection checklist.

Steganography

steghide extract -sf image.jpg
zsteg image.png              # PNG/BMP analysis
stegsolve                    # Visual analysis

• Binary border stego: Black/white pixels in 1px image border encode bits clockwise
• FFT frequency domain: Image data hidden in 2D FFT magnitude spectrum; try np.fft.fft2 visualization
• DTMF audio: Phone tones encoding data; decode with multimon-ng -a DTMF
• Multi-layer PDF: Check hidden comments, post-EOF data, XOR with keywords, ROT18 final layer
• SSTV + LSB: SSTV signal may be red herring; check 2-bit LSB of audio samples with stegolsb
• SVG keyframes: Animation keyTimes/values attributes encode binary/Morse via fill color alternation
• PNG chunk reorder: Fix chunk order: IHDR → ancillary → IDAT (in order) → IEND
• File overlays: Check after IEND for appended archives with overwritten magic bytes

See steganography.md for full code examples and decoding workflows.

PDF Analysis

exiftool document.pdf        # Metadata (often hides flags!)
pdftotext document.pdf -     # Extract text
strings document.pdf | grep -i flag
binwalk document.pdf         # Embedded files

Advanced PDF stego (Nullcon 2026 rdctd): Six techniques -- invisible text separators, URI annotations with escaped braces, Wiener deconvolution on blurred images, vector rectangle QR codes, compressed object streams (mutool clean -d), document metadata fields.

See steganography.md for full PDF steganography techniques and code.

Disk / VM / Memory Forensics

# Disk images
sudo mount -o loop,ro image.dd /mnt/evidence
fls -r image.dd && photorec image.dd

# VM images (OVA/VMDK)
tar -xvf machine.ova
7z x disk.vmdk -oextracted "Windows/System32/config/SAM" -r

# Memory (Volatility 3)
vol3 -f memory.dmp windows.pslist
vol3 -f memory.dmp windows.cmdline
vol3 -f memory.dmp windows.netscan
vol3 -f memory.dmp windows.dumpfiles --physaddr <addr>

# String carving
strings -a -n 6 memdump.bin | grep -E "FLAG|SSH_CLIENT|SESSION_KEY"

# Coredump
gdb -c core.dump  # info registers, x/100x $rsp, find "flag"

See disk-and-memory.md for full Volatility plugin reference, VM forensics, VMware snapshots, deleted partition recovery, ZFS forensics, and ransomware analysis.

Windows Password Hashes

# Extract with impacket, crack with hashcat -m 1000
python -c "from impacket.examples.secretsdump import *; SAMHashes('SAM', LocalOperations('SYSTEM').getBootKey()).dump()"

See windows.md for SAM details and network.md for NTLMv2 cracking from PCAP.

Bitcoin Tracing

• Use mempool.space API: https://mempool.space/api/tx/<TXID>
• Peel chain: ALWAYS follow LARGER output; round amounts indicate peels

Uncommon File Magic Bytes

Magic	Format	Extension	Notes
OggS	Ogg container	.ogg	Audio/video
RIFF	RIFF container	.wav,.avi	Check subformat
%PDF	PDF	.pdf	Check metadata & embedded objects
GCDE	PrusaSlicer binary G-code	.g, .bgcode	See 3d-printing.md

Common Flag Locations

• PDF metadata fields (Author, Title, Keywords)
• Image EXIF data
• Deleted files (Recycle Bin $R files)
• Registry values
• Browser history
• Log file fragments
• Memory strings

WMI Persistence Analysis

Pattern (Backchimney): Malware uses WMI event subscriptions for persistence (MITRE T1546.003).

python PyWMIPersistenceFinder.py OBJECTS.DATA

• Look for FilterToConsumerBindings with CommandLineEventConsumer
• Base64-encoded PowerShell in consumer commands
• Event filters triggered on system events (logon, timer)

See windows.md for WMI repository analysis details.

Network Forensics Quick Reference

• TFTP netascii: Binary transfers corrupted; fix with data.replace(b'\r\n', b'\n').replace(b'\r\x00', b'\r')
• TLS weak RSA: Extract cert, factor modulus, generate private key with rsatool, add to Wireshark
• USB audio: Extract isochronous data with tshark -e usb.iso.data, import as raw PCM in Audacity
• NTLMv2 from PCAP: Extract server challenge + NTProofStr + blob from NTLMSSP_AUTH, brute-force

See network.md for SMB3 decryption, credential extraction, and linux-forensics.md for full TLS/TFTP/USB workflows.

Browser Forensics

• Chrome/Edge: Decrypt Login Data SQLite with AES-GCM using DPAPI master key
• Firefox: Query places.sqlite -- SELECT url FROM moz_places WHERE url LIKE '%flag%'

See linux-forensics.md for full browser credential decryption code.

Additional Technique Quick References

• Docker image forensics: Config JSON preserves ALL RUN commands even after cleanup. tar xf app.tar then inspect config blob. See linux-forensics.md.
• Linux attack chains: Check auth.log, .bash_history, recent binaries, PCAP. See linux-forensics.md.
• PowerShell ransomware: Extract scripts from minidump, find AES key, decrypt SMTP attachment. See disk-and-memory.md.
• Linux ransomware + memory dump: If Volatility is unreliable, recover AES key via raw-memory candidate scanning and magic-byte validation; re-extract zip cleanly to avoid missing files/false negatives. See disk-and-memory.md.
• Deleted partitions: testdisk or kpartx -av. See disk-and-memory.md.
• ZFS forensics: Reconstruct labels, Fletcher4 checksums, PBKDF2 cracking. See disk-and-memory.md.
• Hardware signals: VGA/HDMI TMDS/DisplayPort, Voyager audio, Flipper Zero. See signals-and-hardware.md.
• G-code visualization: Side projections (XZ/YZ) reveal text. See 3d-printing.md.
• Git directory recovery: gitdumper.sh for exposed .git dirs. See linux-forensics.md.

HTTP Exfiltration in PCAP

Quick path: tshark --export-objects http,/tmp/objects extracts uploaded files instantly. Check for multipart POST uploads, unusual User-Agent strings, and exfiltrated files (images with flag text). See network.md.

Common Encodings

echo "base64string" | base64 -d
echo "hexstring" | xxd -r -p
# ROT13: tr 'A-Za-z' 'N-ZA-Mn-za-m'

ROT18: ROT13 on letters + ROT5 on digits. Common final layer in multi-stage forensics. See linux-forensics.md for implementation.