name: ctf-malware
description: Malware & network analysis: obfuscated JS/PowerShell/VBA, PE/.NET analysis, PyInstaller/PyArmor, custom C2 protocols (RC4, AES, DNS), YARA rules, shellcode, memory-forensics IOCs, anti-sandbox/anti-VM bypass.
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 Malware & Network Analysis
Quick reference for malware analysis CTF challenges. Each technique has a one-liner here; see supporting files for full details with code.
Additional Resources
- scripts-and-obfuscation.md - JavaScript deobfuscation, PowerShell analysis, eval/base64 decoding, junk code detection, hex payloads, Debian package analysis, dynamic analysis techniques (strace/ltrace, network monitoring, memory string extraction, automated sandbox execution), YARA rules for malware detection, shellcode analysis (Unicorn Engine, Capstone), memory forensics for malware (Volatility 3 malfind, process injection detection), anti-analysis techniques (VM detection, timing evasion, API hashing, process injection)
- c2-and-protocols.md - C2 traffic patterns, custom crypto protocols, RC4 WebSocket, DNS-based C2, network indicators, PCAP analysis, AES-CBC, encryption ID, Telegram bot recovery, Poison Ivy RAT Camellia decryption
- pe-and-dotnet.md - PE analysis (peframe, pe-sieve, pestudio), .NET analysis (dnSpy, AsmResolver), LimeRAT extraction, sandbox evasion, malware config extraction, PyInstaller+PyArmor
Pattern Recognition Index
Dispatch on byte/file signals, never the sample's reputation.
| Signal | Technique → file |
|---|
File starts with PK + contains package.json + .vsix extension | VSCode extension activation-event exfil → scripts-and-obfuscation.md |
High-entropy extension.js/index.js > 50 KB with child_process | JS obfuscator.io / JSFuck deobfuscation → scripts-and-obfuscation.md |
PowerShell -enc <b64> or IEX in parent process logs | PS script decode + reflection assembly → scripts-and-obfuscation.md |
| PCAP with custom TCP port, payload bytes distributed uniformly | Custom crypto / RC4 / AES session key recovery → c2-and-protocols.md |
PCAP with DNS TXT records carrying base32/64 blobs | DNS-based C2 exfil → c2-and-protocols.md |
| PCAP where specific User-Agent receives non-default responses | UA-gated C2 path-hex-XOR → (see ctf-forensics/network-advanced.md) |
PE32/PE64 with .text sections having packer signatures (UPX, VMProtect, Themida) | Unpacking + dump-after-decrypt → pe-and-dotnet.md |
| .NET assembly with obfuscated strings + reflection calls | dnSpy + de4dot + string decryption → pe-and-dotnet.md |
PyInstaller binary (MEIPASS, _MEIxxxx strings) | pyinstxtractor + pycdc → pe-and-dotnet.md |
Process-injection IoCs in memory dump (RWX allocations, NtUnmapViewOfSection) | Volatility malfind + process hollowing detection → scripts-and-obfuscation.md |
Anti-VM checks (cpuid hypervisor bit, RDTSC timing, specific drivers) | VM-detection bypass in analysis sandbox → scripts-and-obfuscation.md |
| WebSocket frame with visible RC4 key-setup or KSA signatures | RC4 WebSocket reversing → c2-and-protocols.md |
Recognize the artefact or protocol pattern. The sample's name is not a signal.
For inline snippets and quick-reference tables, see quickref.md. The Pattern Recognition Index above is the dispatch table — always consult it first.
