Apple today released iOS 6.1.3, an update to its mobile OS which contains "improvements and bug fixes". Perhaps the most importantly though, Apple has finally fixed the lock screen (aka. passcode) bug which allowed potential miscreants to bypass lock screens protected by a password.

The flaw allowed users to circumvent the lock screen by following a series of steps (YouTube video). The exploit -- simple enough to perform in seconds -- involved placing (and immediately canceling) an emergency call followed by pressing the lock button twice.

The unfortunate bug was introduced with iOS 6.1 and has remained present since its January 28 release. However, last month we mistakenly reported that iOS 6.1.2 resolved the lock screen flaw. Despite a small number of news outlets making this claim, that wasn't the case.

Meanwhile, a two-month absence of a fix has likely been stressful for IT managers. Despite implementing even the best possible security policies and practices, countless iPhone and iPads utilized by large-scale operations have been at risk to this incredibly simple exploit.

The previous iOS 6.1.2 update patched an Exchange calendar bug which was responsible for poor battery life and egregious network usage.

iOS 6.1.3 has been made available to all compatible iPhones, iPads and iPod Touches. Users can install the update through iTunes or OTA under Settings > General > Software Update.

Jailbreakers should steer clear from 6.1.3 until jailbreaking is officially supported. While iOS 6.1.3 beta 2 was making the rounds in the past weeks, there were reports that Apple had patched a vulnerability which evasi0n exploits to root iOS.