CVE-2021-0403 in Android
Summary
by MITRE • 02/27/2021
In netdiag, there is a possible information disclosure due to a missing permission check. This could lead to local information disclosure with System execution privileges needed. User interaction is not needed for exploitation. Product: Android; Versions: Android-11; Patch ID: ALPS05475124.
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Analysis
by VulDB Data Team • 03/05/2021
The vulnerability identified as CVE-2021-0403 resides within the netdiag component of Android 11 systems, representing a critical information disclosure flaw that undermines system security through inadequate permission validation mechanisms. This vulnerability specifically affects the network diagnostic functionality that is integral to Android's networking stack and system monitoring capabilities. The flaw manifests when the netdiag service fails to properly validate permissions before exposing sensitive network information, creating a pathway for unauthorized access to system data that should remain restricted to privileged processes.
The technical implementation of this vulnerability stems from a missing permission check within the netdiag service that operates with system-level privileges. When the service processes network diagnostic requests, it does not adequately verify whether the requesting process possesses the necessary authorization levels to access the requested information. This omission allows malicious applications or processes running with system execution privileges to bypass normal access controls and retrieve confidential network configuration data, routing information, and potentially other sensitive system diagnostics. The vulnerability operates at the kernel level within Android's system services architecture, making it particularly dangerous as it can be exploited by code that already holds system-level execution rights.
The operational impact of this vulnerability extends beyond simple information disclosure, as the exposed data could provide attackers with comprehensive insights into the device's network configuration and connectivity status. Attackers could leverage this information to map network topologies, identify potential attack vectors, and gather intelligence for further exploitation. The fact that this vulnerability requires system execution privileges for exploitation means that it could be particularly devastating if an attacker successfully escalates privileges through other means, as they would then gain access to a broad range of network diagnostic information that could be used for advanced persistent threat activities. This vulnerability directly aligns with CWE-284, which addresses improper access control issues in software systems.
Mitigation strategies for CVE-2021-0403 should focus on implementing proper permission validation mechanisms within the netdiag service and ensuring that all system-level diagnostic functions enforce strict access controls. Android developers should implement comprehensive permission checking before exposing any sensitive network information, utilizing the existing Android security framework to validate process credentials and authorization levels. The patch provided with ALPS05475124 addresses this specific vulnerability by adding the missing permission checks and ensuring that only authorized processes can access the network diagnostic information. Security professionals should also consider implementing network monitoring to detect anomalous access patterns to diagnostic services and establish proper privilege separation to minimize the impact if such vulnerabilities are exploited. This vulnerability demonstrates the critical importance of maintaining robust access control mechanisms in system services and aligns with ATT&CK technique T1059, which covers command and scripting interpreter usage for privilege escalation and information gathering activities. Organizations should ensure that all Android devices are updated with the latest security patches and that proper security configurations are maintained to prevent unauthorized access to sensitive system diagnostic information.