Multiple Users Remotely Failing To Authenticate From Host

Multiple Users Remotely Failing To Authenticate From Host

Description

The following analytic identifies a source host failing to authenticate against a remote host with multiple users. This behavior could represent an adversary performing a Password Spraying attack against an Active Directory environment to obtain initial access or elevate privileges. Event 4625 documents each and every failed attempt to logon to the local computer. This event generates on domain controllers, member servers, and workstations. Logon Type 3 describes an remote authentication attempt.\ The detection calculates the standard deviation for each host and leverages the 3-sigma statistical rule to identify an unusual number of users. To customize this analytic, users can try different combinations of the bucket span time and the calculation of the upperBound field. This logic can be used for real time security monitoring as well as threat hunting exercises.\ This detection will trigger on the host that is the target of the password spraying attack. This could be a domain controller as well as a member server or workstation.\ The analytics returned fields allow analysts to investigate the event further by providing fields like source process name, source account and attempted user accounts.

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Multiple Users Remotely Failing To Authenticate From Host Help

To successfully implement this search, you need to be ingesting Windows Event Logs from domain controllers as as well as member servers and workstations. The Advanced Security Audit policy setting Audit Logon within Logon/Logoff needs to be enabled.

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