CVE-2018-5887 in Android
Summary
by MITRE
While processing the USB StrSerialDescriptor array, an array index out of bounds can occur in Android releases from CAF using the linux kernel (Android for MSM, Firefox OS for MSM, QRD Android) before security patch level 2018-06-05.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 04/05/2023
The vulnerability identified as CVE-2018-5887 represents a critical array index out of bounds condition that affects Android devices utilizing Qualcomm Snapdragon chipsets and the Linux kernel. This flaw manifests during the processing of USB StrSerialDescriptor arrays, which are essential components in USB device enumeration and identification processes. The vulnerability specifically impacts Android releases from the Common Android Framework (CAF) that incorporate the Linux kernel, affecting not only standard Android implementations but also Firefox OS for MSM and QRD Android variants. The issue exists within the kernel-level USB subsystem where serial number descriptors are handled, creating a potential attack surface that could be exploited by malicious actors to disrupt device functionality or potentially escalate privileges.
The technical root cause of this vulnerability stems from inadequate bounds checking during USB descriptor processing within the kernel's USB subsystem. When the system encounters a USB device with a StrSerialDescriptor array, the kernel fails to properly validate the array indices before accessing memory locations. This allows for unauthorized memory access patterns that can result in buffer overflows or out-of-bounds reads. The flaw specifically occurs in the USB serial number descriptor handling code where the system processes device identification information without sufficient validation of array boundaries. According to CWE-129, this represents an implementation flaw where insufficient input validation leads to memory corruption, while the ATT&CK framework would categorize this under privilege escalation techniques through kernel-level memory corruption vulnerabilities. The vulnerability's presence in multiple Android variants including CAF, Firefox OS, and QRD Android indicates a widespread impact across Qualcomm-based device ecosystems.
The operational impact of CVE-2018-5887 extends beyond simple system instability to potentially enable more severe security consequences. An attacker could exploit this vulnerability to cause device crashes, denial of service conditions, or in more sophisticated scenarios, potentially leverage the memory corruption to execute arbitrary code with kernel privileges. The vulnerability affects devices prior to security patch level 2018-06-05, meaning that users with older firmware versions remain at risk. The nature of USB descriptor processing makes this particularly concerning as USB connections are frequently used for device communication, charging, and data transfer operations. This vulnerability could be exploited through malicious USB devices or in scenarios where an attacker gains physical access to a device. The risk assessment indicates this vulnerability could be classified under CVSS score of 7.8, representing high severity due to its potential for privilege escalation and system instability.
Mitigation strategies for CVE-2018-5887 primarily focus on applying the relevant security patches released by device manufacturers and Google. Organizations should prioritize updating all affected devices to security patch level 2018-06-05 or later, which includes kernel-level fixes for the USB descriptor processing code. System administrators should implement robust patch management procedures to ensure timely deployment of security updates across all Android devices within their environment. Additional defensive measures include implementing USB device whitelisting policies, restricting USB functionality in high-security environments, and monitoring for unusual USB connection patterns that might indicate exploitation attempts. The vulnerability demonstrates the importance of proper bounds checking in kernel code and reinforces the need for comprehensive input validation in system-level components. Security teams should also consider implementing intrusion detection systems that can identify anomalous USB behavior patterns and establish incident response procedures specifically addressing kernel-level memory corruption vulnerabilities. Device manufacturers should conduct thorough code reviews of USB subsystem implementations and ensure proper testing of descriptor handling code to prevent similar vulnerabilities in future releases.