CVE-2021-0516 in Android
Summary
by MITRE • 06/21/2021
In p2p_process_prov_disc_req of p2p_pd.c, there is a possible out of bounds read and write due to a use after free. This could lead to remote escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-11 Android-8.1 Android-9 Android-10Android ID: A-181660448
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Analysis
by VulDB Data Team • 06/24/2021
The vulnerability identified as CVE-2021-0516 represents a critical security flaw within the Android peer-to-peer provisioning discovery process implementation. This issue resides in the p2p_process_prov_disc_req function within the p2p_pd.c source file, where a use after free condition creates opportunities for unauthorized privilege escalation. The vulnerability affects multiple Android versions including Android 8.1, 9, 10, and 11, indicating a widespread impact across the Android ecosystem. The flaw stems from improper memory management during peer-to-peer provisioning discovery operations, where freed memory locations are subsequently accessed without proper validation, creating a predictable attack surface for malicious actors.
The technical nature of this vulnerability manifests as both out of bounds read and write operations, which occur due to the use after free condition in the peer-to-peer provisioning discovery mechanism. When the system processes provisioning discovery requests, it fails to properly validate memory references after objects have been freed, allowing attackers to manipulate memory contents and potentially execute arbitrary code with elevated privileges. This type of vulnerability falls under CWE-416, which specifically addresses use after free conditions, and aligns with ATT&CK technique T1068, which covers exploitation of remote code execution vulnerabilities. The memory corruption occurs during the processing of peer-to-peer discovery requests, where the system attempts to access freed memory structures, leading to potential privilege escalation from regular user context to system level privileges.
The operational impact of CVE-2021-0516 is severe as it enables remote privilege escalation without requiring any additional execution privileges or user interaction for exploitation. This means that an attacker could potentially compromise Android devices simply by sending malicious peer-to-peer provisioning discovery requests, making the vulnerability particularly dangerous in mobile environments where devices frequently engage in peer-to-peer communications. The lack of user interaction requirements significantly increases the attack surface and exploitability, as the vulnerability can be triggered through automated network-based attacks. This type of remote code execution vulnerability represents a critical threat to Android device security, potentially allowing attackers to gain full system control, access sensitive user data, and install malicious applications without user consent.
Mitigation strategies for CVE-2021-0516 should focus on immediate patching of affected Android versions, with priority given to the most recent security updates from Google and device manufacturers. Organizations should implement network monitoring to detect suspicious peer-to-peer provisioning discovery traffic patterns that might indicate exploitation attempts. The vulnerability requires proper memory management practices including null pointer checks, proper object lifecycle management, and validation of memory references before access. Device manufacturers should consider implementing additional security controls such as kernel address space layout randomization and stack canaries to make exploitation more difficult. Regular security audits of peer-to-peer and provisioning discovery implementations should be conducted to identify similar memory management flaws. System administrators should also monitor for unusual system behavior or unauthorized privilege escalation attempts that might indicate successful exploitation of this vulnerability. The fix typically involves ensuring that memory objects are not accessed after being freed, implementing proper reference counting, and adding bounds checking to prevent out of bounds memory operations during provisioning discovery processing.