CVE-2021-0904 in Android
Summary
by MITRE • 12/15/2021
In SRAMROM, there is a possible permission bypass due to an insecure permission setting. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation. Patch ID: ALPS06076938; Issue ID: ALPS06076938.
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Analysis
by VulDB Data Team • 12/22/2021
The vulnerability identified as CVE-2021-0904 resides within the SRAMROM component of a mobile device firmware ecosystem, representing a critical permission bypass flaw that enables local privilege escalation. This issue manifests through insecure permission settings that allow unauthorized access to system resources typically restricted to privileged execution contexts. The vulnerability specifically affects the firmware level implementation where memory protection mechanisms fail to properly enforce access controls, creating a pathway for malicious code execution with system-level privileges. The flaw does not require user interaction for exploitation, making it particularly dangerous as it can be triggered automatically during normal device operation or through automated attack vectors.
The technical implementation of this vulnerability stems from improper access control enforcement within the SRAMROM memory management subsystem. When the system initializes or processes specific memory operations, it fails to validate the privilege level of requesting processes against the protected memory regions. This creates a condition where unprivileged processes can access memory areas that should only be accessible to system-level components with elevated execution privileges. The flaw operates at the kernel level where memory protection units should enforce strict access controls but instead permit unauthorized access patterns that bypass normal security boundaries.
From an operational impact perspective, this vulnerability represents a severe threat to device security and user privacy. Local privilege escalation allows attackers to gain system-level execution privileges without requiring physical access or user interaction, enabling them to modify critical system files, install malicious applications, access encrypted data, and potentially establish persistent backdoors. The attack surface extends beyond simple privilege escalation to include potential data exfiltration, system corruption, and complete device compromise. This vulnerability affects the integrity and confidentiality of all data stored on the device, as well as the overall security posture of the mobile platform.
The mitigation strategy for CVE-2021-0904 requires immediate firmware updates that address the insecure permission settings within the SRAMROM component. Device manufacturers should implement proper access control validation mechanisms that enforce strict privilege checks before allowing memory access operations. This aligns with the principle of least privilege as outlined in cybersecurity frameworks and represents a fundamental requirement for secure system design. Security patches should include comprehensive permission validation routines that verify execution context before granting access to protected memory regions, ensuring that only authorized system processes can access sensitive areas. Additionally, continuous monitoring and runtime protection mechanisms should be implemented to detect and prevent exploitation attempts.
This vulnerability demonstrates characteristics consistent with CWE-284 (Improper Access Control) and aligns with ATT&CK techniques related to privilege escalation and persistence. The insecure permission settings create a direct pathway for attackers to escalate privileges without user interaction, which falls under the ATT&CK tactic of privilege escalation. The issue also represents a failure in the defense-in-depth strategy where multiple security controls should have prevented unauthorized access to system resources. Proper implementation of access control mechanisms, including runtime checks and privilege validation, should have prevented this vulnerability from existing in the first place, highlighting the importance of secure coding practices and thorough security testing during the development lifecycle.