Content Filtering companies have gained quite a bit of traction in the Computer Network Defense (CND) industry. The goal of content filtering is to attempt to stem the carnage that malicious sites can wreak on unsuspecting individuals and companies by blocking access to malware and other forms of ransomware.
The filtering engines work by way of proxying requests between the end user and the destination site. They are performing a “man in the middle” attack between the user and the destination by a number of different ways such as DNS cache poisoning (Cisco’s Umbrella), and content interception (Symantec’s Bluecoat). Filtering engines use a combination of human control and machine learning to differentiate safe sites from malicious sites. Even more than static understanding of sites, filtering engines can identify when a safe site is hijacked and will block traffic when that known safe site is compromised.
Identifying safe sites is not precise nor exact — the task is all a best effort. The beginning of the best effort is listing your site in the filtering engines. If you don’t have your site listed as “safe” by the content filter company, you will likely be blocked!
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