Enhancing Cyber Resilience: Insights from CISA Red Team Assessment of a US Critical Infrastructure Sector Organization

CISA performed a red team assessment of a U.S. critical infrastructure organization in which the team leveraged a leftover web shell and insecure configurations (no_root_squash NFS, unpatched XXE, unprotected private keys, weak DMZ segmentation) to escalate privileges, move laterally into the internal network, compromise Active Directory via Kerberos abuses (S4U2Self, golden tickets, DCSync), and access multiple sensitive business systems; the advisory maps the activity to MITRE ATT&CK, documents defender detection gaps, and provides prioritized mitigations for defenders and software manufacturers.