CVE-2017-2399 in iOS
Summary
by MITRE
An issue was discovered in certain Apple products. iOS before 10.3 is affected. The issue involves the "Pasteboard" component. It allows physically proximate attackers to read the pasteboard by leveraging the use of an encryption key derived only from the hardware UID (rather than that UID in addition to the user passcode).
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Analysis
by VulDB Data Team • 11/21/2022
This vulnerability resides within Apple's iOS operating system affecting versions prior to 10.3 and specifically targets the pasteboard component which serves as a temporary storage mechanism for data copied or cut by users. The pasteboard functionality allows users to transfer information between applications through a shared clipboard system that should theoretically maintain security boundaries. However, the flaw stems from the encryption implementation where the system relies solely on the hardware unique identifier or UID for deriving encryption keys rather than combining this with the user's passcode as a security enhancement. This design choice creates a critical weakness in the cryptographic protection mechanism that Apple employs to safeguard user data within the pasteboard system.
The security implications of this vulnerability extend beyond simple data exposure as it represents a fundamental flaw in Apple's approach to device encryption and data protection. Attackers exploiting this weakness can physically approach a locked device and extract information from the pasteboard without requiring authentication or knowledge of the user's passcode. This attack vector aligns with the concept of physical proximity attacks and demonstrates how insufficient cryptographic key derivation processes can compromise the security model of mobile operating systems. The vulnerability essentially allows unauthorized access to clipboard contents through a method that bypasses traditional authentication mechanisms, making it particularly concerning for users who may not be aware of the security implications of their clipboard data.
The operational impact of this vulnerability is significant as it affects the core privacy and security assumptions of iOS devices, particularly concerning sensitive information that users might copy to their clipboard. This includes but is not limited to passwords, personal identification numbers, confidential messages, or other sensitive data that users might transfer between applications. The vulnerability essentially undermines the security boundary that should exist between different applications and the device's protected state, allowing attackers to access data that was intended to be protected by the device's lock screen and encryption mechanisms. The attack requires only physical proximity to the device, making it particularly dangerous in environments where devices might be left unattended or where unauthorized access could occur in public spaces.
The technical flaw manifests in the cryptographic implementation where the system fails to properly combine hardware identifiers with user authentication factors to generate secure encryption keys for pasteboard data. This design decision violates fundamental security principles that require multi-factor authentication for sensitive data protection and aligns with common cryptographic weaknesses identified in the CWE database under categories related to weak cryptographic key derivation and insufficient entropy in encryption key generation. The vulnerability demonstrates how the absence of proper key derivation functions that incorporate user passcodes or biometric authentication can create security holes that allow attackers to bypass intended protection mechanisms. This weakness represents a failure in the system's security architecture where the principle of least privilege is violated, as data that should remain protected by user authentication can be accessed through alternative means.
Mitigation strategies for this vulnerability primarily involve updating to iOS version 10.3 or later where Apple implemented proper cryptographic key derivation that incorporates user passcodes into the encryption process for pasteboard data. Users should immediately upgrade their devices to ensure protection against this specific attack vector and should also practice good security hygiene by clearing clipboard contents regularly and being mindful of sensitive information stored in the pasteboard. System administrators and security professionals should monitor for devices running vulnerable iOS versions and ensure proper patch management protocols are in place. The vulnerability also highlights the importance of implementing proper cryptographic practices and the necessity of combining multiple authentication factors in security implementations. Organizations should consider the broader implications of such vulnerabilities in their mobile device management strategies and ensure that their security policies account for the risks associated with clipboard data exposure and physical proximity attacks.