CVE-2014-4386 in iOS
Summary
by MITRE
Race condition in the App Installation feature in Apple iOS before 8 allows local users to gain privileges and install unverified apps by leveraging /tmp write access.
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Analysis
by VulDB Data Team • 02/16/2022
The vulnerability described in CVE-2014-4386 represents a critical race condition within Apple iOS's application installation mechanism that existed prior to iOS version 8. This flaw specifically targets the temporary file handling process during app installation, creating a window of opportunity for malicious actors to exploit system security measures. The vulnerability stems from insufficient synchronization mechanisms that allow concurrent access to temporary directories, particularly the /tmp filesystem location where installation processes temporarily store critical application components. The race condition occurs when the system fails to properly validate file integrity and ownership during the installation sequence, enabling unauthorized modifications to installation packages.
The technical implementation of this vulnerability leverages the fact that local users with write access to the /tmp directory can manipulate temporary files during the app installation process. When iOS processes an application installation, it creates temporary files in the /tmp directory to stage the application components before final installation. The race condition manifests when an attacker can replace or modify these temporary files between the time they are created and when they are validated, allowing the system to install malicious code that bypasses normal verification procedures. This type of vulnerability falls under CWE-362, which specifically addresses race conditions in software development, and represents a classic example of improper access control in temporary file handling.
The operational impact of this vulnerability extends beyond simple privilege escalation to enable full application installation bypass mechanisms. Local users who can write to /tmp can effectively install unverified applications that would normally be rejected by iOS's security framework, including applications that may contain malware or unauthorized system modifications. This vulnerability undermines the core security model of iOS, which relies on strict verification of application signatures and integrity checks. Attackers can exploit this weakness to install malicious applications that persist on the device and potentially maintain access even after system restarts. The vulnerability also enables attackers to circumvent code signing requirements and other security controls that normally prevent unauthorized application installation.
Mitigation strategies for this vulnerability require both immediate system updates and defensive configuration measures. The most effective solution involves updating to iOS version 8 or later, where Apple implemented proper synchronization mechanisms and enhanced validation procedures for temporary file handling during installation processes. System administrators should also implement additional security controls such as restricting write access to /tmp directories for non-privileged users and monitoring for unauthorized file modifications in temporary locations. The remediation aligns with ATT&CK technique T1546.001, which covers changes to system execution paths, and demonstrates the importance of proper file system permissions and race condition prevention in mobile operating systems. Organizations should also consider implementing mobile device management solutions that can detect and prevent installation of unauthorized applications, while maintaining regular security assessments to identify similar vulnerabilities in other system components.