AlienVault develops and maintains several security solutions, one of the most famous ones is its OSSIM. In building these tools, the AlienVault team comes across many threats, just as they describe it in their website:
Our people constantly monitor, analyse, reverse engineer and report on sophisticated zero-day threats including malware, botnets, phishing campaigns are more. Through this team of dedicated and renowned security experts, AlienVault contributes code, documentation, analysis and research results in various forms to the security community, to educate it and to make the world a more secure place for all of us.The AlienVault team has very kindly put one of their malicious URL datasets at our disposal so that VirusTotal's URL scanner can query it, they also publish some statistics about what they are seeing in the wild in their Open Source IP Reputation Portal.
Once again, we would like to thank AlienVault in helping us improve VirusTotal and we look forward to other malicious URL/domain datasets/characterization tools contacting us to be included in VirusTotal.