GEN:SID 1:2275
Message SMTP AUTH LOGON brute force attempt
Summary This event is generated when an attempt is made to gain access to an
SMTP server using brute force methods.
Impact Attempted remote access.  
This event may indicate that an attacker is attempting to guess username and password combinations.  
Alternately, it may indicate that an authorized user has entered an
incorrect username and password combination a number of times.
Detailed Information An SMTP server will issue an error message after a failed login attempt.  
This may be an indication of an attacker attempting brute force guessing
of username and password combinations.  It is also possible that an authorized
user has incorrectly entered a legitimate username and password combination.  

This event will be generated after a number of failed attempts.
Affected Systems SMTP servers.
Attack Scenarios An attacker may attempt to guess username and password combinations.
Ease of Attack Simple
Corrective Action  
Additional References