Threat Intelligence on Current, Active Malicious Domains

SURBL Domain Reputation data

The industry’s most comprehensive and accurate list of bad domains:

  • Updated every 1-2 minutes
  • Accurate, effective list of 1,500,000 – 2,000,000 ‘current, active’ bad domains.

Used by Security Vendors, AntiSpam Solutions, Service Providers and Enterprise worldwide to improve their defenses against fast flux, bot generated, and malicious domains.

  • Email Filtering
  • Web Filtering
  • Security Solutions

What is SURBL?


SURBL provides a highly accurate and highly dynamic list of current, active, bad domains; providing up to date threat data on malicious websites.   SURBL is highly effective at identifying and controlling the hard to detect phishing, malware and bot-net domains.   SURBL data contains approx 1.5 million current, active, bad domains, is updated continuously (updated every 1-2 minutes), and greatly improves detection of phishing, malware and bot-net domains.

SURBL data are used to help evaluate web site reputation in commercial and open source mail filters, security appliances, and a wide range of mail and web applications and systems

  • Fast, dynamic intel to identify Advanced phishing, malware data sources
  • Our customers (email providers, filter vendors, security vendors) find SURBL to be a very high value source of intel, and an excellent addition to their solutions.

This Domain reputation datafeed is the industry’s most comprehensive and accurate list of bad domains and is used by security vendors, webmail providers, large and small ISPs, universities, private companies, governments, service providers, and enterprises worldwide to improve defenses against fast-flux, bot-generated, malicious domains.

  • SURBL ( is an independent anti-spam and cyber security research group that has been providing unparalleled insight into malicious & spam-related domain activity for over the past 17+ years.
  • SURBL’s expertise lies in domain intelligence and is its core competency.
  • As a product of their commitment and passion to protect the Internet and its users, their team of highly experienced cyber security researchers have grown to be a trusted member of the internet ecosystem, developing and leveraging direct, trusted relationships with many of the largest technology, security, and messaging providers on all continents, including direct relationships with the industry’s leading registries and registrars.

SURBL’s Reliability & Commitment to Accuracy:

The focus is on actionable intelligence, delivered with near-zero false positives, which can be deployed and used to block malicious activity in near real time.

  • SURBL obsesses on accuracy—and in all cases errs on the side of caution.
  • SURBL understands that accuracy is paramount, and ensures the data delivered contains usable, actionable data…not just noise and false alarms.
  • SURBL invests a great amount of resources and commitment to a policy in which accuracy of the data is paramount. The accuracy has been demonstrated and supported in numerous trials, and by the current users and partners of SURBL.

How to use SURBL

Email Filtering:
The first stage of defense is an email blacklist like Spamhaus Zen, which detects about 80% to 90% of unsolicited messages at the message transfer agent (MTA). The second stage mail filter then checks messages in the body of websites against SURBLs*, allowing the mail filter to detect more than 75% of the remaining unsolicited messages. Together, Spamhaus and SURBL detect more than 95%** of unsolicited messages.

Security Data:
SURBL data provides real-time threat intelligence and is used extensively in security applications. You get quality data thanks to highly sophisticated processing and filtering engines, in addition to manual reviewing and whitelisting, to ensure a highly accurate and effective list.

*SURBLs should be used along with multiple, weighted factors to classify messages

**When used in combination with Spamhaus, SURBLs can detect more than 95% of unsolicited messages.

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