CVE-2012-3734 in iOS
Summary
by MITRE
Office Viewer in Apple iOS before 6 writes cleartext document data to a temporary file, which might allow local users to bypass a document s intended (1) Data Protection level or (2) encryption state by reading the temporary content.
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Analysis
by VulDB Data Team • 04/13/2021
The vulnerability described in CVE-2012-3734 represents a critical security flaw in Apple iOS versions prior to 6.0, specifically affecting the Office Viewer component that handles document processing. This issue stems from improper handling of temporary file creation during document operations, creating a significant bypass mechanism for data protection controls that should otherwise safeguard sensitive information. The vulnerability manifests when iOS applications process Office documents through the built-in viewer, which creates temporary files containing unencrypted document content during rendering and manipulation processes.
The technical root cause of this vulnerability lies in the absence of proper encryption or access control mechanisms for temporary files created during document processing operations. When iOS applications open or manipulate Office documents, they generate temporary files in the file system to store intermediate processing data. These temporary files are created without implementing appropriate security measures such as encryption, restricted file permissions, or secure temporary storage locations. This design flaw allows local malicious processes or users with access to the device to directly read the temporary files and extract sensitive information that would normally be protected by the document's intended data protection level or encryption state.
The operational impact of this vulnerability extends beyond simple data exposure, as it fundamentally undermines the security model that iOS implements to protect user data. When documents are opened with data protection levels such as "Data Protection Level 1" or encryption states that should prevent unauthorized access, the temporary file creation process creates a window of vulnerability where sensitive content becomes accessible through the temporary file system. This bypass mechanism can affect various document types including word processing files, spreadsheets, and presentation documents that users might expect to remain protected during processing. The vulnerability is particularly concerning because it operates at the system level, allowing unauthorized access to information that should remain protected by the device's built-in security mechanisms.
This vulnerability aligns with CWE-312 (Cleartext Storage of Sensitive Information) and CWE-255 (Credentials Management) categories, as it involves storing sensitive data in cleartext format within temporary files. The issue also relates to ATT&CK technique T1005 (Data from Local System) and T1059 (Command and Scripting Interpreter) as attackers can leverage this weakness to extract sensitive information from temporary files without requiring elevated privileges. The vulnerability demonstrates a failure in secure coding practices regarding temporary file handling and demonstrates the importance of implementing proper temporary file security measures such as secure temporary storage locations, appropriate file permissions, and encryption of temporary data. Organizations and users should consider this vulnerability as part of a broader threat landscape that emphasizes the need for comprehensive mobile device security practices, including regular system updates, proper application sandboxing, and awareness of potential bypass mechanisms that can undermine data protection controls.
The remediation for this vulnerability required Apple to implement proper temporary file handling mechanisms in iOS 6.0 and subsequent versions, ensuring that temporary files created during document processing operations are either encrypted, stored in secure locations with restricted access permissions, or deleted immediately after processing completion. This fix demonstrates the importance of secure temporary file management in mobile operating systems and highlights how seemingly minor implementation flaws can create significant security vulnerabilities that affect the entire device security model. Users should prioritize updating to iOS 6.0 or later versions to mitigate this risk and ensure that their device's data protection mechanisms function as intended.