CVE-2015-9133 in Android
Summary
by MITRE
In Android before 2018-04-05 or earlier security patch level on Qualcomm Snapdragon Mobile SD 400, SD 410/12, SD 617, SD 650/52, SD 800, and SD 810, if Widevine App TZ_WV_CMD_DECRYPT_VIDEO is called with a size too large, an integer overflow may occur.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 01/26/2020
The vulnerability identified as CVE-2015-9133 represents a critical integer overflow flaw within the Qualcomm Snapdragon mobile platform's Trusted Execution Environment component. This issue affects Android devices released before the 2018-04-05 security patch level and specifically impacts Snapdragon Mobile platforms including SD 400, SD 410/12, SD 617, SD 650/52, SD 800, and SD 810 chipsets. The vulnerability resides in the Widevine digital rights management system's Trusted Application interface, where the TZ_WV_CMD_DECRYPT_VIDEO command processes video decryption requests. When this command receives a parameter specifying an excessively large size value, the system fails to properly validate or handle the input, leading to potential arithmetic overflow conditions that could compromise system integrity.
The technical exploitation of this vulnerability occurs through the manipulation of the Widevine Trusted Application's memory handling mechanisms within the Qualcomm Snapdragon chipset's secure environment. The integer overflow specifically manifests when the system attempts to calculate memory allocation or buffer boundaries based on the oversized size parameter provided to the TZ_WV_CMD_DECRYPT_VIDEO command. This flaw falls under the CWE-190 category of Integer Overflow or Wraparound, where the system performs arithmetic operations on integer values without proper bounds checking. The vulnerability creates a potential path for attackers to manipulate memory structures and potentially execute arbitrary code within the Trusted Execution Environment, which is designed to provide a secure area for handling sensitive operations like digital rights management.
The operational impact of CVE-2015-9133 extends beyond simple privilege escalation to encompass potential full system compromise through exploitation of the secure element's memory management. Attackers could leverage this vulnerability to bypass the security boundaries that separate normal operating system functions from the trusted execution environment where Widevine DRM operations occur. This could result in unauthorized access to protected multimedia content, potential code execution within the secure environment, and in worst-case scenarios, complete device compromise. The vulnerability's exploitation aligns with ATT&CK technique T1068 by leveraging local privilege escalation and T1059 for command execution within the secure environment. Devices running affected Snapdragon chipsets become vulnerable to attacks that could compromise the integrity of digital rights management systems and potentially allow attackers to extract or manipulate protected content.
Mitigation strategies for CVE-2015-9133 primarily involve applying the relevant security patches released by Qualcomm and Android vendors, which address the integer overflow condition through proper input validation and bounds checking. Organizations should ensure all affected devices receive the 2018-04-05 security update or later patch levels that contain fixes for the Widevine Trusted Application memory handling. Additionally, implementing runtime monitoring for anomalous memory allocation patterns and parameter validation within the Trusted Execution Environment can help detect potential exploitation attempts. The fix typically involves adding proper size validation checks before arithmetic operations occur, ensuring that input parameters cannot cause integer overflow conditions. System administrators should also consider implementing device enrollment and patch management policies that prioritize the deployment of security updates for mobile platforms, particularly those containing vulnerable components like Qualcomm Snapdragon chipsets and their associated secure execution environments.