Just like the PDF exploit which was found by the jailbreak community and fixed thanks to @saurik before iOS 4.0.2 released, we now await another big one from Stefan Esser, a security consultant and application developer for Germany-based SektionEins. He's busy working on adding a security feature known as ASLR (Address Space Layout Randomization) which is currently absent from all iOS devices which will keep your jailbroken devices secure. It works by randomizing the memory locations where injected code is executed. This makes it impossible for threats to know ahead of time where the malicious code are located. If you look at operating systems, Vista had ASLR built into it and the same goes with Windows Mobile 7. In comparison, Apple's Mac OS X also features ASLR but they have left it out completely in iOS.

At a conference scheduled for next week, Stefan plans to unveil a new jailbreaking method that would re-enforce all iOS devices with ASLR by reordering contents of dyld_shared_cache, which is a massive file that houses the libraries. This will be presented at the Power of Community security conference on December 17 in Seoul, South Korea. They also plan to release a tool (tentatively called antid0te) that would simplify the process.

Currently, all jailbroken iOS devices automatically loose another security feature known as DEP (Data Execution Protection) and application sandboxing that can make your device vulnerable to attacks. If everything goes as planned, then according to Stefan, we will finally see the day when a jailbroken iOS device will be more secure than the ASLR protection used on the Mac OS X. Now there's certainly no reason for you to not jailbreak your iOS device.