CVE-2015-1085 in iOS
Summary
by MITRE
AppleKeyStore in Apple iOS before 8.3 does not properly restrict a certain passcode-confirmation interface, which makes it easier for attackers to verify correct passcode guesses via a crafted app.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 05/03/2022
The vulnerability identified as CVE-2015-1085 resides within AppleKeyStore component of iOS versions prior to 8.3, representing a significant security flaw in the mobile operating system's passcode validation mechanism. This weakness specifically targets the passcode confirmation interface that is designed to verify user-entered passcodes during setup or modification processes. The vulnerability stems from insufficient input validation and access control measures that govern how the system responds to passcode verification attempts, creating an exploitable condition that undermines the fundamental security posture of iOS devices.
The technical flaw manifests through improper restriction of the passcode confirmation interface, allowing malicious applications to infer whether a guessed passcode is correct by observing the system's response behavior. This occurs because the legitimate passcode confirmation process does not adequately differentiate between valid and invalid passcode attempts in a way that prevents side-channel analysis. Attackers can craft specialized applications that systematically test passcode combinations and monitor the system's reaction patterns to determine when a correct guess has been made, effectively enabling brute force attacks against device passcodes without triggering typical security mechanisms that would normally prevent such attempts.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it creates a pathway for attackers to systematically compromise iOS devices through automated passcode guessing. This flaw particularly affects users who rely on shorter or predictable passcodes, as the vulnerability reduces the effective entropy required to break device protection. The attack vector requires only a crafted application installed on the target device, making it particularly dangerous in scenarios where users may unknowingly install malicious software or where social engineering tactics are employed to gain access to the device. The vulnerability essentially undermines the authentication security model that iOS employs to protect user data and device integrity.
Security researchers have classified this vulnerability under CWE-284, which deals with improper access control mechanisms, and it aligns with ATT&CK technique T1212, which involves exploitation of system vulnerabilities to bypass security controls. The flaw demonstrates a critical gap in Apple's security architecture where the system's response to authentication attempts provides insufficient obfuscation to prevent attackers from distinguishing between correct and incorrect passcode entries. Mitigation strategies should include immediate updating to iOS 8.3 or later versions where Apple implemented proper passcode confirmation restrictions, along with implementing additional security measures such as device encryption, regular security audits, and user education about the dangers of installing untrusted applications. Organizations should also consider network-level protections and monitoring for suspicious application installation patterns to detect potential exploitation attempts.