CVE-2021-25393 in Smart Phone
Summary
by MITRE • 06/11/2021
Improper sanitization of incoming intent in SecSettings prior to SMR MAY-2021 Release 1 allows local attackers to get permissions to access system uid data.
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Analysis
by VulDB Data Team • 06/14/2021
The vulnerability identified as CVE-2021-25393 represents a critical security flaw in the Android operating system's permission handling mechanisms within the SecSettings component. This issue specifically affects devices running SMR MAY-2021 Release 1 and earlier versions, where the system fails to properly sanitize incoming intent parameters that are processed by the Settings application. The flaw resides in the improper validation of user input that flows through the intent system, creating a pathway for malicious local applications to exploit the system's permission model. The vulnerability is categorized under CWE-20 as an improper input validation, specifically manifesting in the failure to sanitize data received through inter-process communication channels. From an operational perspective, this vulnerability enables local attackers who have already gained some level of access to the device to escalate their privileges and gain unauthorized access to system uid data. The attack vector requires the attacker to be running a local application with sufficient privileges to send malicious intents to the SecSettings component. This represents a privilege escalation vulnerability that can be leveraged to access sensitive system information that should normally be restricted to system-level processes and applications with appropriate permissions. The security implications extend beyond simple data access as this vulnerability can potentially allow attackers to extract system-level information that could be used for further exploitation or to understand the underlying system architecture. The ATT&CK framework categorizes this vulnerability under privilege escalation techniques, specifically T1068 which involves exploiting legitimate credentials or privileges to gain access to restricted resources. The improper sanitization allows attackers to manipulate the intent parameters in ways that bypass the normal permission checks that should prevent unauthorized access to system-level data. This vulnerability particularly impacts devices where the Android security model relies heavily on proper intent handling and permission validation to maintain system integrity. The flaw essentially creates a backdoor through which local applications can circumvent the normal access controls that should protect system uid data from unauthorized access. The vulnerability affects the core Android security framework's ability to maintain proper isolation between different application contexts and system services, undermining the fundamental security boundaries that protect sensitive system information. Security researchers have noted that this vulnerability can be particularly dangerous in environments where multiple applications are running with varying levels of privilege, as it provides a method for lower-privileged applications to access data that should remain protected. The exploitation of this vulnerability requires minimal privileges but can result in significant security implications, making it a prime target for attackers seeking to gain deeper access to mobile devices. The vulnerability demonstrates a critical failure in the Android security model's input validation mechanisms, where the system assumes that incoming intent data is trustworthy without proper sanitization checks. This represents a fundamental breakdown in the principle of least privilege, where applications should only be granted access to resources necessary for their operation. The impact of this vulnerability extends to enterprise environments where mobile device management systems rely on proper permission handling to protect corporate data. Organizations should consider this vulnerability as a potential entry point for more sophisticated attacks that could lead to complete device compromise or data exfiltration. The proper mitigation involves ensuring that all incoming intent data is properly validated and sanitized before being processed by system components. This includes implementing robust input validation mechanisms that can detect and reject malicious intent parameters. The vulnerability also highlights the importance of regular security updates and patch management programs that can quickly address such flaws before they can be exploited in the wild. Mobile security professionals should monitor for indicators of compromise related to this vulnerability and implement appropriate network monitoring to detect potential exploitation attempts. The fix for this vulnerability requires system-level modifications to ensure that intent parameters are properly sanitized before being processed by the SecSettings component, preventing attackers from manipulating the permission system to access restricted data. This represents a classic example of how input validation failures can lead to privilege escalation and unauthorized access to sensitive system resources, emphasizing the critical importance of proper security controls in mobile operating systems.
The vulnerability demonstrates how local privilege escalation can occur through improper input handling in system-level components, particularly affecting the Android security model's ability to enforce proper access controls. The lack of sanitization creates a direct pathway for malicious applications to bypass normal permission checks and access system uid data that should remain protected. This vulnerability type falls under the broader category of insecure input handling that can lead to various security issues including data exposure and privilege escalation. The ATT&CK framework classification of this vulnerability as a privilege escalation technique emphasizes the serious nature of the flaw and its potential impact on overall system security. Organizations should prioritize patching this vulnerability as it represents a significant risk to mobile device security and could be exploited to gain unauthorized access to sensitive system information. The vulnerability also underscores the importance of maintaining up-to-date security practices and the need for continuous monitoring of security advisories to ensure timely response to emerging threats.