Security in Apple's iOS 7 Weaker, Not Stronger, than iOS 6
iOS 6 introduced several security mitigations to make it more difficult for hackers to leverage well-known attacks against operating systems – such as buffer overflows and the zone free list pointer overwrite. Such mitigations, including memory layout randomization, depend on the generation of a random number at boot. So with their introduction in iOS 6, Apple included a new PRNG called early_random() that, explains Azimuth researcher Tarjei Mandt, "leveraged a fairly simple generator that derived values directly from the CPU tick count and a seed (provided by iBoot)."