CVE-2018-4379 in iOS
Summary
by MITRE
A lock screen issue allowed access to the share function on a locked device. This issue was addressed by restricting options offered on a locked device. This issue affected versions prior to iOS 12.0.1.
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Analysis
by VulDB Data Team • 08/22/2023
The vulnerability identified as CVE-2018-4379 represents a significant security flaw in Apple's iOS operating system that compromised the integrity of the device's lock screen protection mechanism. This issue specifically affected devices running iOS versions prior to 12.0.1, creating a window of opportunity for unauthorized access to shared content and functions even when the device appeared to be securely locked. The flaw fundamentally undermined the core security principle that a locked device should prevent access to its functionality and data until proper authentication is provided.
The technical nature of this vulnerability stems from insufficient restrictions on the lock screen interface, allowing users to bypass normal authentication requirements and access the share function directly from the locked state. This represents a failure in the operating system's privilege escalation controls and demonstrates a weakness in the authentication flow that should have prevented such access. The vulnerability essentially created a backdoor through the lock screen mechanism that could be exploited without proper authorization, making it particularly concerning from a cybersecurity perspective.
From an operational standpoint, this vulnerability posed significant risks to user privacy and data security, as it enabled unauthorized individuals to access and potentially share sensitive information when a device was locked. The impact extended beyond simple data exposure to include potential misuse of the device's sharing capabilities, which could have led to unauthorized content distribution or data leakage. This type of vulnerability is particularly dangerous because it operates at the user interface level where users expect maximum protection and security.
The remediation for this vulnerability involved implementing stricter controls on the lock screen interface to prevent access to sharing functions and other potentially sensitive operations. Apple addressed this issue by modifying the lock screen behavior to restrict available options and ensure that proper authentication was required before any sharing or sensitive functions could be accessed. This fix aligns with the principle of least privilege and demonstrates the importance of maintaining strict access controls even at the most basic user interface levels. The vulnerability is categorized under CWE-284, which deals with improper access control, and represents a clear violation of the security principle that unauthorized users should not be able to access system functions. This issue also relates to ATT&CK technique T1547.001, which involves system service modifications that could potentially be exploited to bypass security controls, though in this case the bypass occurred through the lock screen rather than system service manipulation. The fix required a fundamental reevaluation of how the lock screen interface handles user interactions and ensures that all system functions remain protected until proper authentication is verified.