CVE-2023-21377 in Android
Summary
by MITRE • 10/30/2023
In SELinux Policy, there is a possible restriction bypass due to a permissions bypass. This could lead to local information disclosure with no additional execution privileges needed. User interaction is not needed for exploitation.
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Analysis
by VulDB Data Team • 11/22/2023
The vulnerability identified as CVE-2023-21377 represents a significant security flaw within SELinux policy implementations that enables unauthorized access to restricted system resources. This issue manifests as a permissions bypass mechanism that allows malicious actors to circumvent mandatory access controls that are fundamental to SELinux security architecture. The vulnerability specifically affects the policy enforcement mechanisms that govern how system processes and users interact with sensitive data and system components, creating a pathway for information disclosure that undermines the core principles of security isolation.
The technical nature of this flaw resides in how SELinux policies evaluate and enforce access controls for specific system resources. When a process attempts to access certain files or system objects, the SELinux policy module should enforce strict permissions based on the security context of both the requesting process and the target resource. However, in this case, the policy evaluation logic contains a gap that allows processes to bypass these controls, potentially accessing information that should remain restricted to authorized users or processes. The vulnerability does not require any special privileges beyond normal user access, making it particularly concerning as it can be exploited by any user with basic system access.
The operational impact of this vulnerability extends beyond simple information disclosure, as it represents a fundamental weakening of the security model that organizations rely upon for system protection. Local information disclosure through this bypass mechanism could expose sensitive system data, configuration files, or user information that should remain protected by SELinux policies. Attackers could potentially gather intelligence about system configurations, user accounts, or other sensitive information that could be leveraged for further exploitation or to craft more sophisticated attacks. This vulnerability essentially undermines the principle of least privilege that SELinux is designed to enforce, allowing unauthorized access to resources that should be protected by mandatory access controls.
The exploitation of CVE-2023-21377 requires no user interaction, which significantly increases its threat potential as it can be automatically triggered by malicious processes without requiring any human intervention or social engineering tactics. This characteristic aligns with ATT&CK framework technique T1068, which covers 'Exploitation for Privilege Escalation' and T1005, 'Data from Local System', making this vulnerability particularly dangerous in environments where SELinux is actively enforcing security policies. The vulnerability's classification as a permissions bypass relates to CWE-284, which addresses 'Improper Access Control' and specifically targets the weakness in access control mechanisms that should prevent unauthorized access to system resources.
Organizations should prioritize immediate mitigation through the application of available patches from their operating system vendors, as this vulnerability represents a persistent threat to system security. System administrators should also conduct thorough security audits to identify any potential exploitation attempts and review SELinux policy configurations to ensure that access controls remain properly enforced. The vulnerability's nature suggests that it may affect multiple Linux distributions that implement SELinux, making coordinated patch management across affected systems essential. Additionally, monitoring for unusual access patterns or information disclosure attempts should be implemented as part of the defensive strategy, as this vulnerability could be used as a reconnaissance tool before more sophisticated attacks are launched. The remediation process should include verification that SELinux policies are correctly configured and that no unauthorized modifications have been made to the security framework that could compound the vulnerability's impact.