CVE-2014-9935 in Android
Summary
by MITRE
In TrustZone an integer overflow vulnerability leading to a buffer overflow could potentially occur in a DRM routine in all Android releases from CAF using the Linux kernel.
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Analysis
by VulDB Data Team • 12/24/2020
The vulnerability identified as CVE-2014-9935 represents a critical security flaw within the TrustZone subsystem of Android devices that utilize the Linux kernel from the CodeAurora Forum. This issue manifests as an integer overflow condition that can potentially lead to a buffer overflow within Digital Rights Management routines, affecting all Android versions that incorporate the Linux kernel from CAF. The vulnerability exists at the intersection of hardware security and software implementation, where the TrustZone technology's security boundaries are compromised through improper integer handling in DRM processing functions.
The technical implementation of this vulnerability stems from insufficient input validation and arithmetic overflow checks within the TrustZone's DRM handling code. When processing digital rights management content, the system fails to properly validate integer values that determine buffer allocation sizes, leading to scenarios where an attacker-controlled integer value can cause the system to allocate insufficient memory for data storage. This overflow condition creates a situation where subsequent data writes exceed the allocated buffer boundaries, potentially allowing arbitrary code execution or system instability. The vulnerability is particularly concerning because it operates within the TrustZone security domain, which is designed to provide a secure execution environment for sensitive operations.
The operational impact of CVE-2014-9935 extends beyond typical software vulnerabilities due to its location within the TrustZone security framework. Attackers could potentially exploit this flaw to bypass security measures designed to protect sensitive content and cryptographic operations, leading to unauthorized access to protected media content or compromise of the secure element. The vulnerability affects devices that rely on CAF's Linux kernel implementations, which are widely used across various Android smartphone and tablet manufacturers, creating a significant attack surface. This issue particularly threatens devices where TrustZone is responsible for handling DRM content, as the compromise of such systems could enable widespread content piracy or unauthorized access to protected digital assets.
Mitigation strategies for this vulnerability require a multi-layered approach addressing both the immediate software fix and broader security posture improvements. Device manufacturers should implement proper integer overflow checks and bounds validation within the TrustZone DRM routines, ensuring that all buffer allocation sizes are properly validated before memory operations occur. The fix should align with CWE-190 standards for integer overflow prevention and follow ATT&CK framework techniques for mitigating privilege escalation and code execution vulnerabilities. Additionally, system updates should include enhanced input validation mechanisms and runtime checks to detect anomalous buffer operations, while security researchers should monitor for similar patterns in other TrustZone implementations that may present analogous vulnerabilities.