CVE-2018-4430 in iOS
Summary
by MITRE
A lock screen issue allowed access to contacts on a locked device. This issue was addressed with improved state management. This issue affected versions prior to iOS 12.1.1.
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Analysis
by VulDB Data Team • 04/18/2020
The vulnerability identified as CVE-2018-4430 represents a critical security flaw in Apple's iOS operating system that compromised the fundamental security boundary between user data and unauthorized access. This issue specifically targeted the lock screen mechanism, creating a pathway for malicious actors to bypass device authentication and gain unauthorized access to sensitive contact information. The vulnerability existed within the iOS versioning prior to 12.1.1, indicating that Apple had not yet implemented the necessary security controls to prevent this specific type of unauthorized data access. The flaw essentially undermined the core security model of mobile devices by allowing state transitions that should have been prevented during device lock states.
The technical implementation of this vulnerability stemmed from inadequate state management within the iOS lock screen framework. When a device was locked, the system failed to properly maintain the security context required to prevent access to protected data elements such as contacts. This represents a classic failure in access control mechanisms where the system did not properly validate the security state before allowing data retrieval operations. The vulnerability could be exploited through specific sequences of user interactions or system calls that manipulated the device's internal state, effectively creating a window of opportunity for unauthorized access to contact information stored on the device. According to CWE standards, this flaw aligns with CWE-284 which describes improper access control, and CWE-362 which addresses concurrent execution using shared resources.
The operational impact of CVE-2018-4430 was significant for iOS users who relied on their devices for personal and potentially sensitive contact information. Attackers could exploit this vulnerability to access phone numbers, email addresses, and other contact details without requiring authentication or bypassing the device's lock screen protection mechanisms. This created a serious privacy concern as it allowed unauthorized individuals to gain access to personal information that could be used for social engineering attacks, identity theft, or other malicious activities. The vulnerability particularly affected users who had not updated to iOS 12.1.1, leaving them exposed to potential exploitation. From an ATT&CK framework perspective, this vulnerability maps to T1552 which covers credentials harvesting, and T1082 which addresses system information discovery, as the exploitation involved accessing system data through compromised security states.
Apple's resolution for this vulnerability involved implementing improved state management protocols that properly enforced the security boundaries between locked and unlocked device states. The fix required modifications to how the iOS operating system handled state transitions and access control validation during device lock operations. This update addressed the root cause by ensuring that when a device was locked, all access to protected data elements including contacts would be properly restricted regardless of the sequence of operations performed. The mitigation strategy focused on strengthening the security context management within the operating system, particularly around the lock screen and authentication state handling. Users were advised to update their iOS installations to version 12.1.1 or later to receive the necessary security patches that addressed this specific vulnerability and restored proper access control mechanisms for device security.