Incidents in Certified Organizations: Certification Reduces Impact by 43% but Does Not Prevent the Event

Analysis of 52 documented security incidents between 2023 and 2025 in organizations holding active ISO 27001 certification at the time of the event revealed that certification does not reduce occurrence probability — the incident rate is comparable to non-certified organizations of the same sector and size — but it does reduce average financial impact by 43% and mean time to respond (MTTR) by 37%. Mean time to detect (MTTD) was reduced by 29%. The most frequent incident types in certified organizations are: ransomware (31% of cases), credential compromise (27%), targeted phishing with lateral escalation (19%), and unauthorized internal access (15%). Recurring execution failures are: identity management controls documented but not monitored in real time (78% of cases), absence of updated incident response drills (63%), and existing audit logs not proactively analyzed (71%). The difference between a certified organization that suffered a serious incident and one that contained it was not the standard itself, but the depth of execution of the 8-9-10 cycle (operation, evaluation, improvement).