2 min Security

Proofpoint discontinues anti-spam service SORBS

Proofpoint discontinues anti-spam service SORBS

Proofpoint recently discontinued its 20-year-old, well-known Spam and Open Relay Blocking System (SORBS) anti-spam service. The cybersecurity company gave no specific reasons for the move, but maintaining the anti-spam service with infected server IP addresses apparently had become too difficult.

After twenty years of operation, the curtain has now fallen on the well-known anti-spam list SORBS. Owner Proofpoint quietly ceased further development of the list on June 5, 2024. As a result, SORBS will no longer receive ‘reputation data,’ the security specialist said in a comment to The Register.

Meanwhile, data from all 18 lists within the service has been removed. However, the anti-spam service’s website is still up and running at the time of writing this article.

Proofpoint has not posted any references or reasons on its website about the departure of the well-known anti-spam service. In its response to The Register, the security specialist argues that the service was terminated for several reasons that would affect the sustainability of SORBS. For another company to acquire the service, would involve excessive operational costs.

SORBS functionality

The 20-year-old anti-spam service originated in university circles and was maintained in Australia by a single Proofpoint employee. It provided free access to a so-called DNS-based Block List (DSNBL) of about 12 million spam servers. These included servers that distributed spam or had been used in phishing attacks and other e-mail threats. In addition to spam servers, the list included hacked and hijacked servers and servers infected with trojans and spreading those.

At its peak, the SORBS database had 200,000 users and was praised for its accuracy. The database also had a support ticketing system to discuss any listing. As a result, SORBS had a wealth of data on spam servers and more. This data, too, is now no longer available.

Concerns at anti-spam community

The demise of SORBS is of great concern to the anti-spam community. Among other things, they fear that malicious spam providers might buy up the domain name to start abusing it. They hope that other providers will eventually decide to take over the database environment. Recovery of this environment would be fairly easy.

Well-known alternatives to the now-lost SORBS include the anti-spam environments SpamCop and Spamhaus.

Also read: Microsoft curbs spam messages with new Exchange limit