What is SBRS and how does it affect message scoring?

SenderBase Reputation Score (SBRS) is a numeric value that is assigned to an IP address based on information from the SenderBase Reputation Score community. SBRS combines the information from different sources to determine if the sending infrastructure is legitimate or if traffic from the infrastructure has been known to be SPAM. To do this, the SBRS pulls it's information from over 25 public blacklists and open proxies and then combines the data with global data from the SenderBase Community to assign a score from -10.0 to +10.0.

• -10.0: Most likely a malicious sender/SPAM email
• 0: Neutral, or there is not enough information received to give a score
• +10.0: Most likely a legitimate email

The higher the number, the more legitimate the sending server is. A score of 10.0 means that the sending server is guaranteed to be legitimate. While a score of -10.0 means the sending infrastructure has been put on a blacklist by the community. 
 

How does this affect scoring in APD?

The SBRS score is one of the many data points APD uses in determining the overall Message Trust Score. Having a lower SBRS score can lower the overall Message Trust Score in some cases. If the sending infrastructure has been put on a blacklist (-10.0 SBRS) the Message Trust Score gets lowered to a Message Trust Score of 1 or less. The exception to this rule is when we are reasonably confident the message came from the sender's infrastructure and the sending domain is tagged as internal or partner. 

We provide you with these details to help you make decisions on if you believe the traffic is legitimately sent from your ecosystem/organization, or if it is a Phishing email sent by someone using your domain maliciously.

For further information on SBRS, please visit the Senderbase/Cisco website.