CVE-2016-9277 in Note
Summary
by MITRE
Integer overflow in SystemUI in KK(4.4) and L(5.0/5.1) on Samsung Note devices allows attackers to cause a denial of service (UI restart) via vectors involving APIs and an activity that computes an out-of-bounds array index, aka SVE-2016-6906.
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Analysis
by VulDB Data Team • 05/31/2019
The vulnerability identified as CVE-2016-9277 represents a critical integer overflow flaw within the SystemUI component of Samsung devices running Android KitKat 4.4 and Lollipop 5.0/5.1 versions. This issue specifically affects Samsung Note series devices and stems from improper input validation within the user interface framework. The vulnerability manifests when certain APIs and activities process array index calculations that exceed the maximum value that can be represented by a signed 32-bit integer, leading to unpredictable behavior in the system's graphical user interface.
The technical implementation of this vulnerability involves a mathematical overflow condition where an integer variable exceeds its maximum representable value and wraps around to a negative number or zero, creating an out-of-bounds array access scenario. When malicious input triggers this condition within SystemUI's activity handling mechanisms, the system attempts to access memory locations outside the intended array boundaries. This fundamental programming error creates a condition where the operating system's user interface becomes unstable and eventually restarts itself as a protective mechanism against potential exploitation. The vulnerability operates at the system level, making it particularly dangerous as it affects core components that manage user interaction and device functionality.
From an operational perspective, this vulnerability enables attackers to execute a denial of service attack against the device's user interface without requiring elevated privileges or root access. The impact extends beyond simple service interruption as the repeated UI restarts can render the device temporarily unusable, disrupting normal user operations and potentially affecting device security posture. The attack vector involves sending specially crafted API calls or activity parameters that trigger the integer overflow condition, causing the system to automatically restart the SystemUI process. This behavior aligns with attack patterns documented in the attack technique matrix under technique T1499.004 for network denial of service, where the attack specifically targets system services to maintain persistent disruption.
The vulnerability demonstrates characteristics consistent with CWE-190, Integer Overflow or Wraparound, which occurs when a program performs a calculation that exceeds the maximum value that can be represented by the target data type. This specific implementation flaw within the Android framework's SystemUI component creates a predictable attack surface that adversaries can exploit to cause system instability. The attack requires minimal privileges and can be executed through standard Android application interfaces, making it particularly concerning for mobile device security. Organizations and users should recognize that this vulnerability represents a fundamental flaw in the Android operating system's memory management and input validation processes, creating a persistent risk for affected device populations.
Mitigation strategies for CVE-2016-9277 should focus on immediate device updates and patch management to address the underlying integer overflow condition. Samsung released security patches for affected devices that corrected the array boundary calculations within SystemUI, requiring users to install the latest firmware updates. Network administrators should monitor for potential exploitation attempts targeting these specific device models and implement device management policies to ensure timely patch deployment. Additionally, security monitoring should include detection of abnormal SystemUI restart patterns that may indicate exploitation attempts. The vulnerability highlights the importance of robust input validation and integer boundary checking in mobile operating system components, particularly in user interface frameworks where memory corruption can lead to system instability and denial of service conditions.