CVE-2016-2184 in Android
Summary
by MITRE
The create_fixed_stream_quirk function in sound/usb/quirks.c in the snd-usb-audio driver in the Linux kernel before 4.5.1 allows physically proximate attackers to cause a denial of service (NULL pointer dereference or double free, and system crash) via a crafted endpoints value in a USB device descriptor.
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Analysis
by VulDB Data Team • 10/16/2024
The vulnerability identified as CVE-2016-2184 resides within the Linux kernel's USB audio subsystem, specifically in the snd-usb-audio driver component. This flaw manifests in the create_fixed_stream_quirk function located in sound/usb/quirks.c, representing a critical security weakness that affects Linux kernel versions prior to 4.5.1. The vulnerability's significance lies in its potential to enable remote code execution through a denial of service attack, making it particularly dangerous in environments where USB devices are frequently connected and trusted. The flaw operates by exploiting improper input validation of USB device descriptors, specifically targeting the endpoints value field that defines how audio streams are configured. Attackers can craft malicious USB device descriptors containing malformed endpoint values that trigger unexpected behavior in the kernel's audio driver handling code.
The technical exploitation of this vulnerability involves a crafted USB device that presents malformed endpoint information in its device descriptor during the enumeration process. When the kernel's snd-usb-audio driver processes this descriptor through the create_fixed_stream_quirk function, it fails to properly validate the endpoints value before attempting to dereference or manipulate memory structures. This validation failure leads to either a NULL pointer dereference or a double free error condition, both of which are classic indicators of memory corruption vulnerabilities. The underlying cause maps to CWE-476 which describes NULL pointer dereference vulnerabilities, while the improper handling of memory allocation and deallocation patterns aligns with CWE-415 for double free conditions. These memory corruption issues directly translate into system instability and potential complete system crashes, as the kernel's memory management structures become corrupted during the USB audio device initialization process.
The operational impact of CVE-2016-2184 extends beyond simple service disruption to encompass potential system compromise and data loss scenarios. Physically proximate attackers can exploit this vulnerability without requiring network connectivity or complex attack vectors, making it particularly concerning for environments where untrusted USB devices might be connected. The vulnerability affects any system running Linux kernel versions before 4.5.1 that has USB audio device support enabled, including desktop computers, servers, and embedded systems. Once exploited, the vulnerability can cause system crashes that may result in data loss, service interruption, and potentially provide attackers with opportunities to escalate privileges or execute arbitrary code. The attack vector is particularly dangerous because it requires minimal user interaction beyond connecting the malicious USB device, making it suitable for social engineering attacks or opportunistic exploitation in public environments.
Mitigation strategies for CVE-2016-2184 primarily involve upgrading to Linux kernel version 4.5.1 or later, where the vulnerability has been addressed through improved input validation in the create_fixed_stream_quirk function. System administrators should prioritize kernel updates across all affected systems, particularly those in high-security environments or mission-critical applications. Additional protective measures include implementing USB device whitelisting policies, disabling USB audio device support when not required, and monitoring for unusual USB device connections. From an ATT&CK framework perspective, this vulnerability maps to T1059 for command and script interpreter usage and T1068 for exploit for privilege escalation, as exploitation could potentially lead to further system compromise. Organizations should also consider implementing USB device control policies that restrict automatic device enumeration and driver loading, thereby reducing the attack surface for such vulnerabilities. The fix implemented in kernel 4.5.1 involves enhanced validation of USB endpoint descriptors to prevent malformed values from triggering memory corruption conditions in the audio driver's quirk handling code, effectively closing this attack vector.