CVE-2009-2796 in iPhone OS
Summary
by MITRE
The UIKit component in Apple iPhone OS 3.0, and iPhone OS 3.0.1 for iPod touch, allows physically proximate attackers to discover a password by watching a user undo deletions of characters in the password.
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Analysis
by VulDB Data Team • 06/15/2017
The vulnerability described in CVE-2009-2796 represents a significant security flaw within Apple's iPhone OS 3.0 and 3.0.1 implementations that affects both iPhone and iPod touch devices. This issue stems from the UIKit component's handling of password input and character deletion sequences, creating an unintended information disclosure mechanism that can be exploited through physical proximity attacks. The vulnerability specifically targets the password entry interface where users can undo character deletions, revealing information about the password structure and potentially enabling attackers to reconstruct passwords through careful observation of user input patterns.
The technical flaw manifests in how the UIKit framework manages the undo functionality within password fields. When users delete characters from a password field, the system maintains a history of these deletions that can be accessed through the undo mechanism. An attacker positioned physically close to the device can observe the sequence of character deletions and subsequent undo operations, which inadvertently reveals the password being entered. This occurs because the undo functionality preserves the order and timing of character removals, allowing an observer to reconstruct the password by analyzing the visual cues of the deletion and undo sequences. The vulnerability essentially transforms the password input process from a secure, obscured interaction into one where the password history becomes visible through the undo mechanism.
From an operational perspective, this vulnerability creates a serious risk for users who may be in physically proximate environments where attackers can observe their screen activities. The attack vector requires only physical proximity, making it particularly dangerous in public spaces, offices, or any environment where users might be observed while entering passwords. The impact extends beyond simple password disclosure, as this vulnerability can be exploited to compromise access to various system functions, applications, and services that rely on password authentication. Security practitioners should note that this represents a form of visual surveillance attack that bypasses traditional authentication security measures, effectively weakening the authentication layer by exposing password entry patterns.
The vulnerability aligns with several cybersecurity frameworks and threat modeling concepts, particularly those related to information disclosure and side-channel attacks. This issue can be categorized under CWE-200 (Information Exposure) and demonstrates characteristics of a side-channel attack where an attacker gains information through observation of system behavior rather than direct exploitation. From the MITRE ATT&CK framework perspective, this vulnerability relates to T1552 (Unsecured Credentials) and T1566 (Phishing) as it enables attackers to obtain credentials through physical observation rather than traditional phishing methods. The attack requires no specialized tools or complex exploitation techniques, making it particularly concerning as it can be executed by adversaries with minimal technical expertise.
Mitigation strategies for this vulnerability should focus on modifying the undo behavior in password fields to prevent the retention of character deletion history. Apple's response would typically involve updating the UIKit framework to disable or obfuscate undo functionality during password entry, ensuring that character deletion operations do not maintain visible history that could be exploited by attackers. System administrators should implement additional security awareness training for users about physical security risks when entering passwords, particularly in public environments. Organizations should also consider implementing additional authentication layers such as biometric authentication or two-factor authentication to provide defense-in-depth against this type of physical proximity attack. The vulnerability underscores the importance of considering all user interaction patterns and their potential security implications in mobile operating system design, particularly for components handling sensitive information such as passwords and authentication credentials.