CVE-2020-27899 in tvOS
Summary
by MITRE • 04/03/2021
A use after free issue was addressed with improved memory management. This issue is fixed in iOS 14.2 and iPadOS 14.2, macOS Big Sur 11.0.1, watchOS 7.1, tvOS 14.2. A local attacker may be able to elevate their privileges.
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Analysis
by VulDB Data Team • 04/08/2021
This vulnerability represents a classic use-after-free condition that emerged in Apple's operating systems, specifically affecting iOS 14.1, iPadOS 14.1, macOS Big Sur 10.16, watchOS 7.0, and tvOS 14.1. The issue stems from improper memory management practices where freed memory blocks are still referenced or accessed by subsequent operations, creating a potential exploitation vector for malicious actors. The vulnerability falls under the Common Weakness Enumeration category CWE-416, which specifically addresses the use of freed memory condition. Such flaws typically occur when developers fail to properly invalidate pointers after memory deallocation, allowing attackers to manipulate the freed memory region for unauthorized operations.
The technical exploitation of this vulnerability enables a local attacker to achieve privilege escalation, a critical security concern that can transform limited user access into administrative privileges. Attackers can leverage the use-after-free condition to overwrite memory structures, inject malicious code, or manipulate system processes to gain elevated access rights. This type of vulnerability aligns with ATT&CK technique T1068, which covers "Local Port Configuration" and privilege escalation methods. The memory corruption aspects of this flaw make it particularly dangerous as it can be used to bypass system security controls and potentially compromise the entire operating system.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it can lead to complete system compromise when exploited successfully. Local attackers with minimal privileges can leverage this flaw to gain root access, potentially allowing them to install malicious software, access sensitive data, modify system configurations, or establish persistent backdoors. The vulnerability affects multiple Apple platforms, increasing its attack surface and making it particularly concerning for organizations using Apple devices in enterprise environments. The fix implemented in iOS 14.2, iPadOS 14.2, macOS Big Sur 11.0.1, watchOS 7.1, and tvOS 14.2 includes enhanced memory management protocols that properly handle deallocation and pointer invalidation processes. Organizations should prioritize immediate deployment of these updates to protect their systems from potential exploitation attempts. The vulnerability demonstrates the importance of proper memory management practices in system security and highlights the need for continuous security auditing of operating system components. Security teams should monitor for indicators of compromise related to privilege escalation attempts and implement additional monitoring measures to detect potential exploitation of similar memory corruption vulnerabilities in their environments.