CVE-2016-6763 in Android
Summary
by MITRE
A denial of service vulnerability in Telephony could enable a local malicious application to use a specially crafted file to cause a device hang or reboot. This issue is rated as High due to the possibility of local permanent denial of service. Product: Android. Versions: 4.4.4, 5.0.2, 5.1.1, 6.0, 6.0.1, 7.0. Android ID: A-31530456.
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Analysis
by VulDB Data Team • 07/20/2020
The vulnerability identified as CVE-2016-6763 represents a critical denial of service flaw within the Android telephony subsystem that allows local malicious applications to trigger device instability through crafted file manipulation. This issue affects multiple Android versions including 4.4.4, 5.0.2, 5.1.1, 6.0, 6.0.1, and 7.0, demonstrating the widespread impact across the Android platform. The vulnerability resides in the telephony service component that processes incoming calls and manages phone-related operations, making it a prime target for exploitation by malicious actors who can leverage this weakness to disrupt normal device functionality. The Android ID A-31530456 indicates this was properly tracked and documented within Google's internal vulnerability management system, highlighting the severity recognized by the platform developers.
The technical exploitation mechanism involves a local malicious application crafting specific file content that, when processed by the telephony subsystem, causes the device to enter an unstable state resulting in either a complete hang or forced reboot. This type of vulnerability typically occurs when the telephony service fails to properly validate or sanitize input data from file operations, leading to buffer overflows, memory corruption, or improper state handling within the telephony processing pipeline. The vulnerability can be classified under CWE-129 as an Improper Validation of Array Index, which is commonly associated with telecommunications and telephony service components that handle external data inputs. The flaw demonstrates characteristics consistent with improper input validation and resource management issues that are frequently exploited in mobile operating systems.
The operational impact of this vulnerability extends beyond simple inconvenience to potentially enable persistent disruption of critical communication services on affected devices. When a device experiences frequent hangs or reboots due to this vulnerability, users lose access to essential telephony functions including making and receiving calls, sending text messages, and accessing emergency services. The high severity rating reflects the potential for permanent denial of service where the device may become unusable until manual intervention occurs through factory resets or system recovery procedures. This vulnerability particularly affects enterprise and government users who rely on consistent communication capabilities, as it can be exploited to create targeted disruptions in critical communication infrastructure. The local nature of the exploit means that any application with sufficient privileges or that has been granted malicious permissions can potentially trigger the vulnerability, making it accessible to both casual attackers and sophisticated threat actors.
Mitigation strategies for CVE-2016-6763 should focus on immediate patch deployment as provided by Google through Android security updates, which typically include enhanced input validation mechanisms and improved error handling within the telephony subsystem. System administrators and device manufacturers should prioritize applying the relevant security patches to all affected Android versions to prevent exploitation. Additionally, users should be educated about the importance of only installing applications from trusted sources and maintaining current security updates. Network-level monitoring should include detection of anomalous telephony service behavior that could indicate exploitation attempts, while mobile device management solutions should implement application whitelisting policies to prevent unauthorized applications from gaining access to telephony services. The vulnerability also underscores the importance of implementing robust input validation mechanisms and proper resource management practices in telecommunications software components, aligning with ATT&CK technique T1489 which covers system shutdown/reboot operations as a method of denial of service. Organizations should also consider implementing behavioral analysis tools that can detect unusual patterns in telephony service operations that may indicate exploitation attempts.