CVE-2012-0644 in iOS
Summary
by MITRE
Race condition in the Passcode Lock feature in Apple iOS before 5.1 allows physically proximate attackers to bypass intended passcode requirements via a slide-to-dial gesture.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 03/21/2021
The vulnerability identified as CVE-2012-0644 represents a critical race condition flaw within Apple iOS passcode lock functionality prior to version 5.1. This security weakness specifically affects the device's lock screen implementation and creates a window of opportunity for attackers to circumvent intended authentication mechanisms. The vulnerability exploits a timing issue that occurs during the transition between the lock screen and the dialer interface, allowing unauthorized access when an attacker is in physical proximity to the device. The race condition manifests when the device processes user interactions and system transitions concurrently, creating a brief period where the passcode protection is temporarily bypassed. This flaw fundamentally undermines the security model that iOS relies upon for protecting user data and device access.
The technical implementation of this vulnerability stems from how iOS handles the transition between the secure lock screen and the slide-to-dial gesture interface. When a user attempts to make a call from the lock screen, the system must quickly process the slide gesture while simultaneously maintaining the security context of the passcode protection. The race condition occurs because the system does not properly synchronize these concurrent operations, allowing an attacker to perform a rapid slide gesture before the passcode verification process completes. This timing discrepancy creates an exploitable window where the device temporarily accepts the slide gesture without requiring passcode verification. The flaw is particularly concerning because it operates at the user interface level and requires no special privileges or network access, making it accessible to attackers with only physical proximity to the target device.
The operational impact of CVE-2012-0644 extends beyond simple unauthorized access to encompass potential data breaches and privacy violations. Attackers can leverage this vulnerability to make emergency calls, access contact lists, and potentially gain entry to other device functions that require passcode verification. The vulnerability affects all iOS devices running versions prior to 5.1, including iPhones, iPads, and iPod touches, creating a widespread security risk across Apple's user base. The attack vector is particularly dangerous because it requires minimal effort and technical knowledge, making it attractive to both casual attackers and more sophisticated threat actors. The vulnerability can be exploited repeatedly and does not require the attacker to have previously compromised the device or possess any special credentials. This makes it a significant concern for enterprise security and personal privacy protection, as it creates a persistent threat that can be exploited at any time during the device's lock screen interaction.
Apple addressed this vulnerability through the iOS 5.1 update, which implemented proper synchronization mechanisms between the lock screen transition and passcode verification processes. The fix involved modifying the system's event handling to ensure that passcode verification occurs before allowing any gesture-based transitions to the dialer interface. Security researchers have classified this vulnerability according to CWE-367, which addresses Time-of-Check to Time-of-Use (TOCTOU) flaws, and it aligns with ATT&CK technique T1548.001 for abuse of credentials. Organizations should ensure all iOS devices are updated to version 5.1 or later to mitigate this risk, while security professionals should monitor for potential exploitation attempts through network traffic analysis or device monitoring systems. The vulnerability serves as a reminder of the importance of proper synchronization in security-critical systems and demonstrates how seemingly minor implementation flaws can create significant security risks. This case study illustrates the necessity of thorough testing of user interface transitions and the potential for timing-based attacks to bypass authentication mechanisms in mobile operating systems.