Allen Holub is convinced we're not really scared enough. At the SD West 2008 conference in Santa Clara this morning, Holub opened his "Introduction to Security" talk with a slide of Homer Simpson in the iconic pose from Edvard Munch's painting "The Scream." "By the end of this talk, I want you to look like Homer here," he said.
"The level of ignorance surrounding security is abysmal," said Holub as he launched into a discussion of why security is a big problem for programmers, and why it's only getting worse.
One big issue, according to Holub, is that automated attacks over the network are getting easier, and that the proliferation of web services and SOA have opened up software to the internet that was never meant to be exposed to the world at large. And secure layers such as ssl are great for tunnelling securely end-to-end, but the simple fact is that most attackers simply pretend to be a trusted party at the end of the tunnel—almost no one tries to break into that tunnel in the middle.
To Holub, security is really something that must be considered from the ground up in software development. He doesn't trust what he calls the "perimiter defenses" type of security, which consists of some sort of hardened shell around inherently vulnerable software. (He includes firewalls in this category, calling them "completely useless.") He likens this to a king defended in a strong castle. If the castle is tough to break through, attackers will often just find another way at the king (destroying his country's economy, placing a usurping rival on the throne, or starting a slander campaign against the king, for instance). No one will try to break down the front door.
According to Holub, you have to make the underlying software inherently secure. How do you do that? By making it good. Since security flaws are by definition bugs, the practices that produce software with the fewest bugs will also often produce the most secure software. Sounds obvious, he says, but it's really the best approach.
But "application security" is a term that Hollub thinks misleads non-technical CEOs into thinking that the application their engineers have built is secure. Any application is only as secure as the "ecosystem" in which it lives. This includes, but is not limited to, the OS, the file system, the development environment ("When was the last time you verified the PGP signature of a code editor you downloaded?", asks Holub), the database, and the Windows Registry.
Holub's suggestions? First of all, language matters. He doesn't like C or C++ due to their buffer overflow vulnerabilities and dangerous type conversions. Scripting languages like PHP are even worse. He recommends Java or C#, although he cautions that they aren't secure, either. The other main thing you can do, according to Holub, is static analysis. He recommends tools from:
Apart from that? Be afraid. Very afraid.