HTB: Expressway

Expressway is a Linux box with only SSH and an IKE VPN service on UDP. I’ll use ike-scan in aggressive mode to leak the VPN identity and capture a pre-shared key hash, which cracks quickly with hashcat. Connecting to the IPSEC VPN doesn’t provide any additional attack surface, but the PSK works for SSH access. For privilege escalation, I’ll show exploitation of two different CVEs in sudo. In…