CVE-2021-0871 in Android
Summary
by MITRE • 09/14/2022
In PVRSRVBridgePMRPDumpSymbolicAddr 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-238921253
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Analysis
by VulDB Data Team • 10/17/2022
The vulnerability identified as CVE-2021-0871 resides within the PowerVR kernel driver's PVRSRVBridgePMRPDumpSymbolicAddr function, representing a critical security flaw that affects Android devices utilizing PowerVR graphics processing units. This issue stems from an inadequate validation mechanism that fails to properly verify input parameters before processing, creating a pathway for malicious actors to exploit integer overflow conditions. The vulnerability is classified under CWE-191 as an Integer Underflow (Wrap or Wraparound) and aligns with ATT&CK technique T1068 which covers Exploitation for Privilege Escalation.
The technical flaw manifests when the kernel driver processes symbolic address information without proper size validation, allowing attackers to manipulate input values that ultimately control heap memory access patterns. This missing size check creates an environment where integer overflow conditions can occur, leading to unauthorized heap memory access beyond intended boundaries. The vulnerability's exploitation does not require user interaction or additional execution privileges, making it particularly dangerous as it can be triggered automatically during normal device operation. The integer overflow specifically affects the heap management routines within the PowerVR driver, potentially allowing attackers to overwrite critical memory structures or inject malicious code into kernel space.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it provides attackers with direct access to kernel-level memory regions that should remain protected. Local privilege escalation means that an attacker with minimal access to the device can potentially gain full system control, including access to all stored data, network communications, and device functionality. The vulnerability affects Android SoC implementations where PowerVR graphics drivers are present, making it widespread across numerous mobile devices that utilize this graphics processing architecture. The lack of user interaction requirement significantly increases exploitability, as the vulnerability can be triggered through normal device operations without requiring physical access or user consent.
Mitigation strategies for CVE-2021-0871 should focus on immediate patch deployment from device manufacturers, as the vulnerability represents a critical threat level that requires urgent attention. Organizations should implement comprehensive monitoring for suspicious kernel memory access patterns and ensure all Android devices receive timely security updates. The fix typically involves implementing proper input validation and size checking mechanisms within the PVRSRVBridgePMRPDumpSymbolicAddr function to prevent integer overflow conditions. Additionally, system administrators should consider implementing kernel memory protection mechanisms such as stack canaries and address space layout randomization to further reduce exploitability. Device manufacturers should also conduct thorough security reviews of kernel driver components to identify similar vulnerabilities that may exist in other graphics processing unit implementations, as this represents a class of vulnerability that could affect multiple hardware components.