How We Cracked a Corporate Network in 4 Hours Using Only Kali Linux and OSINT

Phase 1: Reconnaissance (45 Minutes)

Before touching a single tool, we conducted passive OSINT. LinkedIn revealed the IT infrastructure team used Cisco ASA firewalls and Palo Alto for perimeter security. Job postings mentioned "VMware vSphere experience required." A GitHub repository belonging to a junior developer contained a hard-coded staging VPN URL in a Python script committed 14 months prior.

From Shodan, we confirmed the VPN endpoint was publicly accessible and running a firmware version from 2021 — two major releases behind, with three published CVEs.

Phase 2: Initial Access (35 Minutes)

CVE-2021-20016, a pre-authentication remote code execution vulnerability in SonicWall SSL-VPN, had a working public PoC. The endpoint matched the vulnerable version. We obtained an unauthenticated shell on the VPN gateway within 35 minutes of starting active exploitation.

From the gateway, we extracted the local credential cache — including a service account used for automated health checks. The account had domain read access and a password that had not been rotated in 3.5 years.

Phase 3: Lateral Movement (90 Minutes)

Using BloodHound to map Active Directory relationships, we identified a shortest path to Domain Admin: service account → IT support group → helpdesk workstation → local admin reuse → domain admin workstation → DA credentials in memory (Mimikatz).

The attack path required three hops. None triggered an alert.

Phase 4: Objective Achievement (30 Minutes)

Domain Admin was achieved 3 hours 20 minutes after engagement start. We demonstrated impact by accessing the financial reporting share, the HR system API, and the backup server — all without triggering SIEM alerts because all movement used legitimate credentials.

Lessons Applied

The client implemented: emergency VPN firmware patching, credential rotation policies (90-day maximum), Privileged Access Workstations for administrators, enhanced SIEM rules for off-hours lateral movement, and removed local admin rights from all workstations.