CVE-2021-0882 in Android
Summary
by MITRE • 04/19/2023
In PVRSRVBridgeRGXKickSync of the PowerVR kernel driver, a missing size check means there is a possible integer overflow that could allow out-of-bounds heap access. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android SoCAndroid ID: A-270395803
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Analysis
by VulDB Data Team • 05/14/2023
The vulnerability identified as CVE-2021-0882 resides within the PowerVR kernel driver's PVRSRVBridgeRGXKickSync function, representing a critical security flaw that undermines the integrity of Android-based systems. This issue manifests as a missing size check that creates an avenue for integer overflow conditions, fundamentally compromising the memory management mechanisms of the graphics processing unit driver. The vulnerability specifically affects Android SoC implementations where the PowerVR graphics hardware is integrated, making it particularly concerning given the widespread adoption of these chipsets across mobile and embedded devices. The Android ID A-270395803 further contextualizes this flaw within the broader Android security framework, indicating that this vulnerability has been recognized and tracked by Google's security team.
The technical implementation of this vulnerability stems from inadequate input validation within the kernel driver's synchronization mechanism. When the PVRSRVBridgeRGXKickSync function processes requests from user-space applications, it fails to properly validate the size parameters associated with heap allocations. This absence of size checking creates a scenario where malicious inputs can cause integer overflow calculations to produce unexpectedly large values, leading to heap memory corruption. The flaw operates at the kernel level where privilege escalation opportunities are most significant, as the integer overflow directly translates into out-of-bounds heap access patterns that can be exploited to manipulate kernel memory structures. According to CWE classification, this represents a variant of CWE-190 Integer Overflow or Wraparound, specifically manifesting in kernel driver contexts where memory corruption can lead to privilege escalation. The ATT&CK framework categorizes this under privilege escalation techniques, particularly leveraging kernel vulnerabilities to gain elevated system privileges without requiring additional user execution privileges.
The operational impact of CVE-2021-0882 extends beyond simple memory corruption, creating a pathway for local privilege escalation that can be leveraged by malicious applications already present on the device. Since no user interaction is required for exploitation, an attacker can potentially exploit this vulnerability through any application that can communicate with the PowerVR driver, making it particularly dangerous in environments where applications have broad permissions. The vulnerability's exploitation potential is further amplified by the fact that it operates at the kernel level, meaning that successful exploitation could grant attackers complete control over the device's graphics processing unit and potentially the entire system. This represents a significant risk to device integrity and user data security, as the attacker could access sensitive information, modify system files, or establish persistent backdoors. The flaw essentially undermines the security boundaries that separate user-space applications from kernel-space operations, creating a direct attack vector for malicious actors seeking to elevate their privileges within the Android security model.
Mitigation strategies for CVE-2021-0882 must address both immediate patching requirements and broader architectural considerations for kernel driver security. Device manufacturers should prioritize the deployment of kernel updates that include proper size validation and integer overflow protection mechanisms within the PVRSRVBridgeRGXKickSync function. The implementation should incorporate comprehensive input validation that prevents size parameters from exceeding acceptable bounds and includes robust overflow detection routines. System administrators should also consider implementing additional security measures such as kernel address space layout randomization and stack canaries to further complicate exploitation attempts. Security monitoring should be enhanced to detect anomalous heap allocation patterns that might indicate exploitation attempts. Organizations should also review their application security policies to limit the permissions granted to applications that interact with graphics processing unit drivers, as this vulnerability can be exploited through legitimate application interfaces. The remediation process should follow established security protocols that include thorough regression testing to ensure that patch implementations do not introduce new compatibility issues while effectively addressing the integer overflow conditions that enable privilege escalation.