Perhaps https://www.opm.gov/cybersecurity/cybersecurity-incidents/opm-cybersecurity-action-report.pdf https://www.opm.gov/cybersecurity/cybersecurity-incidents/

Perhaps https://www.opm.gov/cybersecurity/cybersecurity-incidents/opm-cybersecurity-action-report.pdf https://www.opm.gov/cybersecurity/cybersecurity-incidents/op... is more informative technically, but this "post-mortem" is a fascinating read for me. It's like The Cuckoo's Egg for modern times, as writ by government subcommittee.