Cyber Safety Review Board
https://www.cisa.gov/resources-tools/groups/cyber-safety-review-board-csrb
While publications to this site are less frequent, the content is typically very impactful globally and reporting is very comprehensive. The "Microsoft Online Exchange Incident from Summer 2023" is an incredible example. Check into this source at least once a month for new publications and announcements.
10k filings
https://www.sec.gov/edgar/search/
On July 26, 2023, the Securities and Exchange Commission adopted new rules to enhance and standardize disclosures regarding cybersecurity risk management, strategy, governance, and incidents by public companies that are subject to the reporting requirements of the Securities Exchange Act of 1934.
You can find recent disclosures on their website by searching for 8-K/A forms using the "Cyber incident" input within the keywords search.
Info Security Magazine
https://www.infosecurity-magazine.com
This website is a frequently cited source for timely breach notifications and breaking cyber news. When looking for general awareness of what is causing breaches, victim identification, congressional testimony, and even TTPs, this resource is a good place to visit daily.
Krebs on Security
https://www.linkedin.com/in/bkrebs?utm_source=share&utm_campaign=share_via&utm_content=profile&utm_medium=android_app
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