CVE-2021-25402 in Notes
Summary
by MITRE • 06/11/2021
Information Exposure vulnerability in Samsung Notes prior to version 4.2.04.27 allows attacker to access s pen latency information.
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Analysis
by VulDB Data Team • 06/14/2021
The vulnerability identified as CVE-2021-25402 represents an information exposure flaw within Samsung Notes application versions prior to 4.2.04.27. This security weakness specifically affects the handling of stylus input data, particularly s pen latency information that should remain protected from unauthorized access. The vulnerability falls under the broader category of information disclosure vulnerabilities that can potentially compromise user privacy and system integrity. According to CWE-200, this represents a weakness where information is exposed to unauthorized actors, which can lead to various downstream security implications. The flaw manifests in how the application processes and stores stylus interaction data, creating an avenue for attackers to extract sensitive timing information associated with pen input operations.
The technical implementation of this vulnerability stems from inadequate input validation and insufficient access controls within the Samsung Notes application. When users interact with the application using a stylus, the system captures and processes latency data that reflects the timing characteristics of pen movements and interactions. This information, while seemingly benign, can reveal patterns about user behavior, device performance, and potentially even assist in fingerprinting attacks. The vulnerability occurs because the application fails to properly sanitize or restrict access to this latency information, allowing malicious actors to extract and analyze these timing measurements. The flaw is particularly concerning as it operates at the application level without requiring elevated privileges, making it accessible through standard exploitation techniques.
The operational impact of this vulnerability extends beyond simple information disclosure, as s pen latency data can serve as a valuable data point for attackers seeking to understand user interaction patterns or device characteristics. This information exposure could potentially be leveraged in combination with other vulnerabilities to conduct more sophisticated attacks, including those targeting user behavior analysis or device fingerprinting. The latency information might reveal details about the specific device model, processing capabilities, or even help in identifying unique user interaction patterns that could be used for tracking purposes. From an attacker perspective, this vulnerability aligns with techniques described in the MITRE ATT&CK framework under the information gathering phase, where adversaries collect data about the target system to plan more effective attacks.
Mitigation strategies for CVE-2021-25402 require immediate deployment of Samsung Notes version 4.2.04.27 or later, which includes proper input sanitization and access control mechanisms for stylus data. Organizations should also implement network monitoring to detect unusual data access patterns that might indicate exploitation attempts. The vulnerability demonstrates the importance of proper data handling practices, particularly for applications that process user interaction data. Security teams should conduct regular vulnerability assessments to identify similar information exposure issues in other applications and mobile platforms. Additionally, users should be educated about the risks of using applications with known vulnerabilities and the importance of keeping software updated. The fix implemented by Samsung likely addresses the root cause by ensuring that latency information is properly secured and only accessible to authorized application components, aligning with security best practices for mobile application development and the principle of least privilege access control.