Complexity, though, is often the enemy of security. Numerous bugs hidden in all of that complicated code can lead to exploitable security vulnerabilities. So defenses need to be balanced among the browser, the operating system and the network. It's the old defense-in-depth philosophy. We should not put all of our infosec eggs solely in the browser basket. The browser can help, but it can also be subverted.
That being said, I do not believe that today's browsers are sufficiently equipped to fight malware. Major browser vulnerabilities are discovered on a regular basis, and attackers install a great deal of malware by exploiting these browser holes. That manipulation will likely continue for some time. The browsers have improved, but all the browser-helper applications that play media files, including QuickTime and Acrobat Reader, and render different languages, like Flash, are proving to be a big security concern. The browser doesn't really prevent these third-party tools from being subverted, even though it invokes them.
Some people may say that it's not the browser's job to protect against errant third-party applications, and that's certainly a defendable argument. If everyone had that reasoning, it would be hard to believe that the browser would play "the greatest role in malware protection."
This was first published in October 2007