CVE-2016-2066 in Linux
Summary
by MITRE
Integer signedness error in the MSM QDSP6 audio driver for the Linux kernel 3.x, as used in Qualcomm Innovation Center (QuIC) Android contributions for MSM devices and other products, allows attackers to gain privileges or cause a denial of service (memory corruption) via a crafted application that makes an ioctl call.
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Analysis
by VulDB Data Team • 08/23/2022
The vulnerability identified as CVE-2016-2066 represents a critical integer signedness error within the MSM QDSP6 audio driver component of the Linux kernel version 3.x series. This flaw specifically affects Qualcomm's Android contributions for MSM devices and extends to various other products utilizing the same kernel components. The vulnerability stems from improper handling of integer values during ioctl system calls, creating a pathway for malicious exploitation that can result in either privilege escalation or system denial of service conditions. The issue manifests when a crafted application executes an ioctl command that triggers the faulty integer comparison logic within the audio driver subsystem.
The technical root cause of this vulnerability lies in the improper treatment of signed versus unsigned integer values within the driver's input validation mechanisms. When processing ioctl requests related to audio parameter configuration, the MSM QDSP6 driver fails to correctly handle the signedness of integer parameters, leading to potential memory corruption scenarios. This type of error falls under the CWE-191 category of "Integer Underflow (Wrap or Wraparound)" and can be classified as a CWE-190 "Integer Overflow or Wraparound" when the signedness error results in unexpected arithmetic behavior. The flaw occurs during the validation of audio driver parameters where unsigned integer values are incorrectly interpreted as signed integers, creating a condition where normal input values can trigger unexpected behavior in the driver's memory management routines.
The operational impact of this vulnerability extends beyond simple denial of service to potentially enable privilege escalation attacks that could allow malicious applications to execute code with elevated privileges. Attackers can exploit this weakness by crafting specific ioctl calls that manipulate the audio driver's integer handling logic, potentially leading to memory corruption that could be leveraged for privilege escalation or system compromise. This vulnerability affects devices running Android versions that incorporate Qualcomm's MSM QDSP6 audio driver components, making it particularly relevant to mobile devices and embedded systems that utilize Qualcomm's hardware platforms. The attack surface is significant as it requires only a malicious application with the ability to make ioctl calls, which is often possible on Android devices with appropriate permissions or through privilege escalation techniques.
Mitigation strategies for CVE-2016-2066 should focus on both immediate patching and defensive programming approaches. Qualcomm and kernel maintainers should implement proper integer type checking and validation within the MSM QDSP6 audio driver, ensuring that unsigned integer parameters are correctly handled without implicit signedness conversion. The fix should involve explicit type casting and bounds checking to prevent the integer signedness error from manifesting. Organizations should prioritize applying the official kernel patches released by Qualcomm and the Linux kernel community, as these updates specifically address the integer handling logic in the audio driver. Additionally, system administrators should implement application whitelisting and monitoring of ioctl calls to detect potential exploitation attempts, particularly on devices running vulnerable kernel versions. The vulnerability demonstrates the importance of proper input validation and integer handling in kernel drivers, aligning with ATT&CK technique T1068 which covers "Exploitation for Privilege Escalation" and emphasizes the need for robust kernel security measures to prevent such vulnerabilities from being exploited in real-world scenarios.