CVE-2018-21053 in Samsung
Summary
by MITRE
An issue was discovered on Samsung mobile devices with N(7.x), O(8.x), and P(9.0) software. There is Clipboard access in the lockscreen state via a physical keyboard. The Samsung ID is SVE-2018-12684 (October 2018).
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Analysis
by VulDB Data Team • 10/07/2020
This vulnerability exists in Samsung mobile devices running Android versions 7.x, 8.x, and 9.0, representing a critical security flaw that compromises the device's lockscreen protection mechanisms. The issue stems from insufficient access controls that allow unauthorized clipboard access when the device is locked, creating a significant attack surface that violates fundamental mobile security principles. The vulnerability was identified and documented by Samsung under their internal security tracking system as SVE-2018-12684, highlighting the severity of the flaw in their security assessment process.
The technical implementation of this vulnerability involves a flaw in the Android framework's lockscreen security model where physical keyboard input can bypass normal authentication requirements to access clipboard content. This occurs because the system fails to properly enforce clipboard access restrictions when the device is in a locked state, allowing any physical keyboard input to potentially trigger clipboard operations that should be restricted to authenticated users only. The flaw essentially creates a backdoor pathway through which malicious actors could access sensitive data stored in the clipboard, including passwords, personal information, and other confidential content that users expect to remain protected when the device is locked.
From an operational perspective, this vulnerability represents a severe threat to user privacy and data security, particularly in environments where mobile devices contain sensitive corporate or personal information. Attackers could exploit this weakness by simply connecting a physical keyboard to the device while it remains locked, potentially accessing clipboard contents that contain authentication credentials, private messages, or other confidential data. The impact extends beyond individual user privacy concerns to include potential corporate security breaches where employees may inadvertently expose sensitive business information through this vulnerability. This type of flaw directly violates security best practices outlined in the National Institute of Standards and Technology cybersecurity framework and represents a failure in the principle of least privilege.
The vulnerability aligns with CWE-284, which addresses improper access control in software systems, and maps to ATT&CK technique T1177 for "Clear Text Credentials" and T1133 for "External Remote Services." Organizations should implement immediate mitigations including applying the latest security patches from Samsung, enabling additional security features such as encrypted storage, and educating users about the risks of connecting external keyboards to locked devices. The recommended approach involves strengthening the lockscreen security model through proper access control enforcement and ensuring that clipboard operations are properly gated by authentication mechanisms. Additionally, security monitoring should be enhanced to detect unusual clipboard access patterns that might indicate exploitation attempts, while users should be advised to avoid using physical keyboards with devices that contain sensitive information. This vulnerability underscores the critical importance of comprehensive security testing and the need for robust access control implementations in mobile operating systems.