CVE-2018-21092 in Samsung
Summary
by MITRE
An issue was discovered on Samsung mobile devices with M(6.x) and N(7.x) software. A crafted AT command may be sent by the DeviceTest application via an NFC tag. The Samsung ID is SVE-2017-10885 (January 2018).
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Analysis
by VulDB Data Team • 10/09/2020
This vulnerability exists within Samsung mobile devices running Android Marshmallow version 6.x and Nougat version 7.x operating systems. The security flaw stems from insufficient input validation mechanisms within the device's telecommunications subsystem, specifically in how it processes AT commands received through NFC communication channels. The DeviceTest application, which is typically pre-installed on Samsung devices, can be exploited by crafting malicious AT commands that are transmitted via NFC tags. This creates a privilege escalation vector where untrusted NFC input can potentially influence the device's communication protocols.
The technical implementation of this vulnerability involves the improper handling of AT command sequences that are normally used for modem communication and device testing purposes. When the DeviceTest application processes NFC-tagged AT commands, it fails to properly validate or sanitize the input parameters before executing them within the device's telephony stack. This lack of input sanitization allows an attacker to inject malicious command sequences that can manipulate the device's communication behavior. The vulnerability is particularly concerning because it leverages NFC as an attack surface, which is often considered a relatively secure communication channel for legitimate device interactions. The Samsung ID SVE-2017-10885 indicates this issue was internally tracked and addressed in January 2018, suggesting the vulnerability had been known and documented before its public disclosure.
The operational impact of this vulnerability extends beyond simple privilege escalation to potentially enable more sophisticated attacks on the device's communication capabilities. An attacker could exploit this flaw to intercept or manipulate cellular communications, potentially gaining unauthorized access to sensitive information transmitted over the mobile network. The vulnerability also represents a significant concern for mobile device security because it demonstrates how legitimate device testing applications can become attack vectors when they improperly handle untrusted input from NFC sources. This type of vulnerability aligns with CWE-20, which describes improper input validation issues, and could potentially be leveraged to achieve persistent access or data exfiltration. The attack vector through NFC tags makes this particularly dangerous in environments where users might encounter maliciously programmed NFC devices in public spaces.
Mitigation strategies for this vulnerability should focus on both immediate device updates and operational security measures. Samsung released security patches to address this specific flaw, which should be applied immediately to all affected devices. Organizations and individuals should implement NFC security policies that restrict or disable NFC functionality when not required for legitimate business purposes. The vulnerability highlights the importance of secure coding practices, particularly around input validation and privilege separation in mobile operating systems. From an ATT&CK framework perspective, this vulnerability could be categorized under privilege escalation techniques and may enable further attacks through command execution capabilities. Network administrators should monitor for unusual telecommunications patterns that might indicate exploitation attempts, and security teams should consider this vulnerability when conducting mobile device security assessments. The incident underscores the need for comprehensive security testing of pre-installed applications, particularly those with elevated privileges and direct access to device hardware interfaces.