CVE-2016-8398 in Android
Summary
by MITRE
Unauthenticated messages processed by the UE. Certain NAS messages are processed when no EPS security context exists in the UE. Product: Android. Versions: Kernel 3.18. Android ID: A-31548486. References: QC-CR#877705.
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Analysis
by VulDB Data Team • 01/04/2017
This vulnerability exists in the Android kernel version 3.18 and affects the handling of NAS (Non-Access Stratum) messages within the UE (User Equipment). The flaw occurs when the system processes certain NAS messages without an established EPS (Evolved Packet System) security context, creating a critical security gap in the mobile network authentication process. The vulnerability is classified under CWE-310 as a cryptographic weakness, specifically involving improper handling of security contexts during network communication. This issue allows unauthorized processing of network messages that should require proper authentication and encryption before being accepted by the device. The Android ID A-31548486 indicates this was tracked as a specific security concern within Google's internal vulnerability tracking system, highlighting its significance in mobile security protocols. The root cause stems from insufficient validation of security context requirements before message processing, which violates fundamental principles of secure communication protocols.
The technical implementation of this vulnerability exploits the absence of proper security context validation within the UE's NAS message processing logic. When a mobile device receives certain NAS messages from the network, it should verify that an appropriate EPS security context exists before proceeding with message handling. However, the kernel implementation fails to enforce this prerequisite check, allowing potentially malicious or malformed messages to be processed without proper authentication. This creates an attack surface where adversaries could manipulate network signaling messages to disrupt normal operation or potentially execute unauthorized actions within the device's communication stack. The vulnerability specifically impacts the kernel's handling of EPS security contexts, which are essential for maintaining secure communication between the mobile device and the network infrastructure. The issue manifests in the kernel's network stack implementation where the security context validation mechanism is either absent or improperly implemented, allowing unauthenticated processing of critical signaling information.
The operational impact of this vulnerability extends beyond simple message processing failures and represents a serious threat to mobile network security and user privacy. An attacker could potentially exploit this weakness to inject malicious network messages that would be processed without proper authentication, leading to potential service disruption, unauthorized access to network resources, or even data interception. The vulnerability affects all Android devices running kernel version 3.18 and earlier, making it particularly concerning given the widespread deployment of these systems. Network operators and device manufacturers face significant risks as this flaw could enable man-in-the-middle attacks or unauthorized network access. The vulnerability's impact is amplified by the fact that it operates at the kernel level, providing attackers with low-level access to critical communication functions. This weakness could potentially be leveraged to escalate privileges or gain deeper access to device functionality, making it a critical concern for mobile security professionals and network administrators.
Mitigation strategies for this vulnerability require immediate implementation of security patches and updates to the Android kernel. Device manufacturers should prioritize rolling out firmware updates that correct the improper handling of NAS messages and enforce proper security context validation before message processing. The fix should implement robust checks to ensure that EPS security contexts are established before any NAS message processing occurs, preventing the acceptance of unauthenticated messages. Network operators should monitor for exploitation attempts and consider implementing additional network-level controls to detect and block suspicious signaling traffic. Security teams should also implement monitoring solutions that can detect anomalous NAS message processing patterns that might indicate exploitation attempts. The mitigation approach should align with industry best practices for kernel security and follow established guidelines for mobile network security. Organizations should conduct thorough testing of patches to ensure they do not introduce regressions in normal device functionality while maintaining the security improvements necessary to address the vulnerability. This vulnerability demonstrates the critical importance of proper security context management in mobile communication systems and highlights the need for comprehensive security testing of kernel-level network protocols.