CVE-2016-6700 in Android
Summary
by MITRE
An elevation of privilege vulnerability in libzipfile in Android 4.x before 4.4.4, 5.0.x before 5.0.2, and 5.1.x before 5.1.1 could enable a local malicious application to execute arbitrary code within the context of a privileged process. This issue is rated as Critical due to the possibility of a local permanent device compromise, which may require reflashing the operating system to repair the device. Android ID: A-30916186.
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Analysis
by VulDB Data Team • 09/30/2022
The vulnerability identified as CVE-2016-6700 represents a critical elevation of privilege flaw within the libzipfile component of Android operating systems. This weakness exists in versions 4.x prior to 4.4.4, 5.0.x prior to 5.0.2, and 5.1.x prior to 5.1.1, affecting a substantial portion of Android devices deployed in 2016. The vulnerability stems from improper handling of zip file operations within the system's file processing framework, creating a pathway for malicious applications to escalate their privileges beyond normal application boundaries. The flaw allows a local attacker to execute arbitrary code within the context of privileged system processes, effectively breaking down the security isolation that normally protects system-level operations from user-space applications.
The technical implementation of this vulnerability involves a buffer overflow or memory corruption issue within the zip file parsing logic of libzipfile. When processing specially crafted zip archives, the library fails to properly validate input data, leading to memory corruption that can be exploited to overwrite critical system memory locations. This memory corruption typically occurs during the extraction or decompression phase of zip file processing, where the system does not adequately check the size or structure of compressed data against allocated buffer boundaries. The vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and CWE-125, which covers out-of-bounds read errors. Attackers can leverage this flaw by crafting malicious zip files that, when processed by the vulnerable system, trigger the memory corruption and subsequently allow code execution with elevated privileges.
The operational impact of CVE-2016-6700 is severe and potentially permanent, as it provides attackers with the ability to gain root-level access to affected devices. Once exploited, the vulnerability enables malicious applications to bypass Android's security model entirely, allowing them to modify system files, install persistent backdoors, access sensitive user data, and potentially compromise the entire device. The attack requires only local execution privileges, making it particularly dangerous as it can be triggered by any application installed on the device without requiring additional permissions or user interaction. This local privilege escalation capability means that even if a device appears secure from external attacks, a malicious application with basic user permissions could potentially compromise the entire system. The severity rating as Critical reflects the potential for complete device compromise that may require full system reinstallation or reflashing to remediate, as noted in the Android ID A-30916186.
Mitigation strategies for CVE-2016-6700 primarily focus on system updates and patches provided by Google and device manufacturers. The most effective solution involves upgrading to patched versions of Android where the libzipfile component has been corrected to properly validate zip file inputs and prevent memory corruption. Organizations and individuals should prioritize immediate patch deployment, as the vulnerability exists in widely deployed Android versions that remain in use across numerous devices. Additional defensive measures include implementing application whitelisting policies to restrict zip file processing, monitoring system logs for suspicious file operations, and conducting regular security assessments of mobile applications. From an ATT&CK framework perspective, this vulnerability maps to T1068, which covers "Exploitation for Privilege Escalation," and T1059, which addresses "Command and Scripting Interpreter" techniques that could be employed following successful exploitation. Network administrators should also consider implementing mobile device management solutions that can enforce security policies and prevent installation of untrusted applications that might exploit this vulnerability.