CVE-2021-25355 in Notes
Summary
by MITRE • 03/25/2021
Using unsafe PendingIntent in Samsung Notes prior to version 4.2.00.22 allows local attackers unauthorized action without permission via hijacking the PendingIntent.
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Analysis
by VulDB Data Team • 04/05/2021
The vulnerability identified as CVE-2021-25355 represents a critical security flaw in Samsung Notes application versions prior to 4.2.00.22 that exploits unsafe PendingIntent usage patterns. This issue stems from the application's improper handling of PendingIntent objects which are fundamental components in android application development for creating intents that can be executed at a later time. The vulnerability specifically manifests when the application creates PendingIntent objects without appropriate security flags, particularly the FLAG_IMMUTABLE flag that was introduced in android api level 23. When PendingIntent objects are created without this flag, they remain mutable and can be manipulated by malicious applications running in the same user context, creating a significant attack surface for local privilege escalation.
The technical exploitation of this vulnerability occurs through a process known as PendingIntent hijacking where an attacker with local access can intercept and modify the PendingIntent objects used by Samsung Notes. This manipulation allows unauthorized actions to be performed on behalf of the vulnerable application, potentially enabling the attacker to execute arbitrary code or access sensitive data. The flaw is particularly dangerous because it operates at the system level where the application's privileges are inherited from the user context, making it possible for local attackers to perform actions that would normally require elevated permissions. This type of vulnerability falls under the CWE-377 weakness category which addresses unsafe handling of potentially sensitive data and improper handling of pending intents, making it a direct threat to the integrity and confidentiality of user data stored within the notes application.
The operational impact of CVE-2021-25355 extends beyond simple data theft to encompass potential system compromise and unauthorized access to sensitive user information. When exploited, this vulnerability allows attackers to perform actions such as reading, modifying, or deleting notes data, potentially accessing personal information, business documents, or confidential communications stored within the application. The attack vector is particularly concerning because it requires minimal privileges and can be executed by any application running on the same device, making it a significant threat in environments where multiple applications are installed. From an attack framework perspective, this vulnerability aligns with the attack technique T1068 which involves exploiting local privilege escalation and T1547 which covers persistence mechanisms through application manipulation. The implications are severe for enterprise environments where Samsung Notes might be used for storing sensitive corporate information, as it could enable attackers to gain unauthorized access to business-critical data without requiring network access or complex exploitation techniques.
Mitigation strategies for this vulnerability focus on immediate application updates and security hardening practices. Samsung addressed this issue by releasing version 4.2.00.22 which properly implements the FLAG_IMMUTABLE flag when creating PendingIntent objects, preventing external manipulation of these critical components. Organizations should ensure that all instances of Samsung Notes are updated to the patched version to eliminate the risk of exploitation. Additionally, system administrators should implement monitoring for suspicious PendingIntent usage patterns and consider applying mobile device management policies that enforce application security requirements. The vulnerability highlights the importance of following secure coding practices as outlined in the OWASP mobile security project which emphasizes the need for proper intent handling and the use of immutable flags for PendingIntent objects. Security teams should also consider implementing runtime application self-protection measures that can detect and prevent unauthorized PendingIntent manipulation attempts, providing an additional layer of defense against similar vulnerabilities in other applications that may not have been patched yet.