CVE-2016-10393 in Android
Summary
by MITRE
In Android for MSM, Firefox OS for MSM, QRD Android, with all Android releases from CAF using the Linux kernel, when processing a clip with large size values, integer arithmetic overflows, and allocated buffer size will be less than intended buffer size. The following buffer operations will overflow the allocated buffer.
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Analysis
by VulDB Data Team • 01/14/2020
This vulnerability exists in Android-based systems utilizing the Linux kernel and affects multiple device platforms including MSM, Firefox OS, and QRD Android releases. The flaw manifests when the system processes clip data structures containing excessively large size parameters that trigger integer arithmetic overflow conditions. The vulnerability stems from inadequate input validation and buffer size calculation mechanisms within the kernel's memory management subsystem. When processing these malformed clip structures, the system performs integer arithmetic operations that exceed the maximum representable values for the data types used, resulting in unexpected buffer sizing calculations. This specific overflow condition causes the allocated memory buffer to be significantly smaller than the intended size required for proper data handling, creating a classic buffer underflow scenario.
The technical implementation of this vulnerability involves the manipulation of clip data structures that contain size fields which, when processed through arithmetic operations, produce integer overflows. According to CWE-190, this represents an integer overflow vulnerability where the overflow occurs during the calculation of buffer sizes. The system's failure to properly validate input parameters before performing arithmetic operations creates a condition where maliciously crafted clip data can trigger the overflow. This type of vulnerability falls under the ATT&CK technique T1059.007 for command and scripting interpreter, as it can be exploited through carefully constructed input that manipulates the kernel's memory allocation behavior. The integer overflow occurs in the context of kernel memory management where the calculated buffer size becomes negative or wraps around to a small positive value, leading to insufficient memory allocation for the actual data processing requirements.
The operational impact of this vulnerability is significant as it creates a potential pathway for privilege escalation and memory corruption attacks. When the allocated buffer is smaller than intended, subsequent memory operations such as memcpy, memmove, or direct memory writes will overflow the allocated space, potentially overwriting adjacent memory regions. This can lead to arbitrary code execution, system crashes, or information disclosure depending on the specific memory corruption patterns. The vulnerability affects all Android releases from CAF (Code Availability Framework) that utilize the Linux kernel, making it widespread across numerous device models and manufacturers. Attackers could exploit this by crafting specially formatted clip data that triggers the integer overflow condition, potentially allowing them to execute malicious code with kernel-level privileges. The vulnerability's exploitation requires understanding of the kernel's memory management subsystem and the specific arithmetic operations that lead to the overflow condition.
Mitigation strategies for this vulnerability include implementing proper input validation and integer overflow checking mechanisms within the kernel's buffer allocation routines. System administrators should ensure that all affected Android devices receive timely security updates from their manufacturers, as this vulnerability affects the core kernel components that handle memory management operations. The fix typically involves adding bounds checking before arithmetic operations that calculate buffer sizes, ensuring that integer overflows are detected and handled gracefully rather than allowing them to proceed to memory allocation. Additionally, implementing stack canaries, address space layout randomization, and other exploit mitigations can reduce the effectiveness of potential exploitation attempts. Organizations should also conduct thorough security testing of kernel components and implement monitoring for unusual memory allocation patterns that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of proper integer arithmetic handling in kernel space, where even seemingly benign input validation failures can lead to severe security consequences.