Logon Logoff Event: 4649

Event ID 4649 – A Replay Attack Was Detected

If the server name, client name, time, and microsecond fields from the Authenticator match are found in the recent entries of the cache, a KRB_AP_ERR_REPEAT Kerbeors response is sent to the client. The sending of this response triggers event ID 4649, which is registered by the corresponding domain controller

This event could occur potentially due to the same packets being sent by a misconfigured network device between the server and the client.

This log data provides the following information:

• Security ID
• Account Name
• Account Domain
• Logon ID
• Account Name (Replayed)
• Account Domain (Replayed)
• Process ID
• Process Name
• Workstation Name
• Detailed Authentication Information

Why does event ID 4649 need to be monitored?

• This event could be a sign of Kerberos replay attack
• It could indicate a network deice configuration or routing problem

Pro Tip:

ADAudit Plus provides real-time pre-configured reports about account logons which help identify miscreant users attempting to logon into machines that require elevated privileges. The reports also provide complete evidence of any action administered by any user. These reports are useful in overcoming account logon audit challenges such as replay attacks.