For more information, please refer to this announcement explaining best practices for getting answers to questions.
Audit report of employees logging on system and check which screens they navigate to
Recently we faced an issue of security breach whereby some users who normally should not have access to the salary and workforce compensation details of all employees from all legal entities; they were able to access these details. This issue was caused because of a wrong security profile which was being used in a custom role and that custom role was assigned to these users. The access issue has been resolved by editing the role setup to remove the wrong security profile and replace it with the correct one.
However, since any user having that particular role, could have accessed these unauthorized details without anyone knowing before the security profile was corrected, is another matter of concern.