Account manipulation may aid adversaries in maintaining access to credentials and certain permission levels within an environment. Manipulation could consist of modifying permissions, modifying credentials, adding or changing permission groups, modifying account settings, or modifying how authentication is performed. These actions could also include account activity designed to subvert security policies, such as performing iterative password updates to subvert password duration policies and preserve the life of compromised credentials. In order to create or manipulate accounts, the adversary must already have sufficient permissions on systems or the domain.
The Mimikatz credential dumper has been extended to include Skeleton Key domain controller authentication bypass functionality. The
Skeleton Key is used to patch an enterprise domain controller authentication process with a backdoor password. It allows adversaries to bypass the standard authentication system to use a defined password for all accounts authenticating to that domain controller.
Use multifactor authentication. Follow guidelines to prevent or limit adversary access to Valid Accounts.
Protect domain controllers by ensuring proper security configuration for critical servers. Configure access controls and firewalls to limit access to these systems. Do not allow domain administrator accounts to be used for day-to-day operations that may expose them to potential adversaries on unprivileged systems.
Collect events that correlate with changes to account objects on systems and the domain, such as event ID 4738.  Monitor for modification of accounts in correlation with other suspicious activity. Changes may occur at unusual times or from unusual systems. Especially flag events where the subject and target accounts differ  or that include additional flags such as changing a password without knowledge of the old password. 
Use of credentials may also occur at unusual times or to unusual systems or services and may correlate with other suspicious activity.
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