CVE-2016-3831 in Android
Summary
by MITRE
The telephony component in Android 4.x before 4.4.4, 5.0.x before 5.0.2, 5.1.x before 5.1.1, and 6.x before 2016-08-01 allows remote attackers to cause a denial of service (device crash) via a NITZ time value of 2038-01-19 or later that is mishandled by the system clock, aka internal bug 29083635, related to a "Year 2038 problem."
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Analysis
by VulDB Data Team • 09/12/2022
The vulnerability identified as CVE-2016-3831 represents a critical denial of service flaw affecting multiple versions of the Android operating system, specifically targeting the telephony component's handling of time values. This issue stems from the classic Year 2038 problem, a well-documented limitation in computer systems that use 32-bit signed integers to represent time values. The vulnerability affects Android versions 4.x before 4.4.4, 5.0.x before 5.0.2, 5.1.x before 5.1.1, and 6.x before the specified date, making it a widespread concern across the Android ecosystem. The flaw manifests when the system receives a Network Identity and Time Zone (NITZ) time value set to January 19, 2038, or later dates, which causes the system clock to malfunction and ultimately leads to device crashes.
The technical root cause of this vulnerability lies in how the Android telephony subsystem processes time zone information received from network operators. When a device receives a NITZ message containing a time value beyond the 32-bit signed integer limit, typically occurring around January 19, 2038, the system fails to properly handle the overflow condition. This results in the system clock becoming corrupted, causing the telephony service to crash and subsequently leading to a complete device freeze or reboot. The vulnerability is classified under CWE-191, Integer Underflow, as the system attempts to process time values that exceed the maximum representable value for 32-bit signed integers, triggering an integer overflow condition. The flaw is particularly insidious because it can be triggered remotely through network messages without requiring any user interaction or authentication.
The operational impact of this vulnerability extends beyond simple device instability, creating potential security concerns for mobile network operators and device manufacturers. Attackers can exploit this weakness by sending specially crafted NITZ messages to vulnerable Android devices, causing widespread service disruption across affected networks. This type of attack falls under the ATT&CK technique T1499.004, "Endpoint Denial of Service," where adversaries target device resources to prevent normal operation. The vulnerability particularly affects devices that rely heavily on automatic time synchronization from network operators, which is common in mobile environments. Organizations using these vulnerable Android versions may experience significant service degradation, as the denial of service can be triggered by legitimate network signals, making it difficult to distinguish between normal operation and malicious activity.
Mitigation strategies for this vulnerability require immediate patching of affected Android versions, with manufacturers releasing security updates that properly handle time values beyond the 32-bit integer limit. System administrators should implement network monitoring to detect and block suspicious NITZ messages that could trigger the vulnerability. The fix involves modifying the telephony component to properly validate and handle time values, ensuring that any date beyond the standard 32-bit signed integer range is either rejected or properly converted to prevent system clock corruption. Additionally, organizations should consider implementing network segmentation to limit exposure and deploy intrusion detection systems that can identify and alert on anomalous time synchronization messages. The vulnerability demonstrates the importance of addressing legacy system limitations in mobile operating systems and highlights the need for comprehensive testing of time-related functions in embedded systems, particularly those that rely on 32-bit time representations.