CVE-2019-15475 in Mi A3
Summary
by MITRE
The Xiaomi Mi A3 Android device with a build fingerprint of xiaomi/onc_eea/onc:9/PKQ1.181021.001/V10.2.8.0.PFLEUXM:user/release-keys contains a pre-installed app with a package name of com.qualcomm.qti.callenhancement app (versionCode=28, versionName=9) that allows unauthorized microphone audio recording via a confused deputy attack. This capability can be accessed by any app co-located on the device. This app allows a third-party app to use its open interface to record telephone calls to external storage.
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Analysis
by VulDB Data Team • 02/20/2024
The vulnerability described in CVE-2019-15475 represents a critical security flaw in the Xiaomi Mi A3 smartphone running Android 9. This device contains a pre-installed application named com.qualcomm.qti.callenhancement which has been identified as a vector for unauthorized microphone access through a confused deputy attack mechanism. The vulnerability stems from improper privilege management within the Android application framework where a legitimate system application is incorrectly configured to expose its functionality to potentially malicious third-party applications. The specific build fingerprint xiaomi/onc_eea/onc:9/PKQ1.181021.001/V10.2.8.0.PFLEUXM indicates this issue affects a particular firmware version of the Xiaomi Mi A3 device. The application version code 28 and version name 9 suggest this is a relatively recent build that still contains the exploitable flaw. This vulnerability aligns with CWE-284 which addresses improper access control and CWE-266 which covers incorrect privilege assignment, both of which are fundamental security principles in software development. The attack vector exploits the confused deputy problem where a trusted application is manipulated by an untrusted application to perform privileged actions on behalf of the malicious actor.
The technical implementation of this vulnerability allows any application co-located on the device to access the microphone recording functionality through an exposed interface within the Qualcomm Call Enhancement application. This interface is designed to facilitate legitimate call recording features but has been improperly secured to allow unauthorized access. The attack enables third-party applications to utilize the open interface of the legitimate application to record telephone calls and store the audio data to external storage locations. This represents a significant privacy breach as users cannot reasonably expect that their call recordings will be protected from unauthorized access by other applications installed on their device. The flaw operates at the application level within the Android security model, specifically targeting the permission system and inter-process communication mechanisms that should normally prevent such cross-application privilege escalation. The vulnerability essentially allows an attacker to bypass normal Android security boundaries and gain access to sensitive microphone data through a legitimate system component.
The operational impact of this vulnerability extends beyond simple privacy concerns to encompass broader security implications for users of the affected device. Any malicious application that gains access to the Qualcomm Call Enhancement application interface can potentially record sensitive conversations without user knowledge or consent. This capability could be exploited for espionage, identity theft, or corporate espionage where unauthorized parties might access confidential business communications or personal conversations. The vulnerability affects all applications installed on the device regardless of their permissions, as the flaw lies within the system application's interface design rather than in individual application permissions. This makes the attack surface particularly broad and difficult to defend against through traditional application permission controls. The persistent nature of the vulnerability means that users cannot simply uninstall the affected application to resolve the issue, as it is a pre-installed system component that requires firmware updates or device re-flashing to address properly. This vulnerability directly relates to ATT&CK technique T1193 which covers reconnaissance and information gathering through system information discovery, and T1059 which covers command and control through application execution.
Mitigation strategies for this vulnerability require both immediate and long-term approaches to address the root cause. Users should avoid installing untrusted applications from unknown sources as these could exploit the vulnerable interface to access microphone functionality. Device manufacturers should prioritize releasing firmware updates that properly secure the application interfaces and implement stricter access controls for system applications. The Android security model should be enhanced to better detect and prevent confused deputy attacks through improved inter-process communication validation. System administrators and security professionals should monitor for unauthorized applications that might attempt to access the vulnerable interface and implement application whitelisting policies where possible. The vulnerability highlights the need for more rigorous security testing of pre-installed applications and better enforcement of Android security guidelines during the development process. Organizations should consider implementing device management policies that restrict application installation and monitor for suspicious behavior patterns that might indicate exploitation attempts. The remediation process should involve updating the Qualcomm Call Enhancement application to properly validate caller permissions and implement proper access controls that prevent unauthorized third-party applications from utilizing its functionality.