CVE-2016-3886 in Android
Summary
by MITRE
systemui/statusbar/phone/QuickStatusBarHeader.java in the System UI Tuner in Android 7.0 before 2016-09-01 does not prevent tuner changes on the lockscreen, which allows physically proximate attackers to gain privileges by modifying a setting, aka internal bug 30107438.
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Analysis
by VulDB Data Team • 09/15/2022
The vulnerability identified as CVE-2016-3886 resides within the System UI Tuner component of Android 7.0 operating systems, specifically affecting versions prior to the 2016-09-01 security update. This flaw exists in the QuickStatusBarHeader.java file which governs the lockscreen interface elements, creating a critical security gap that undermines the device's fundamental security posture. The issue represents a privilege escalation vulnerability that allows attackers with physical proximity to the device to manipulate system settings through the lockscreen interface, bypassing normal security controls that should prevent such modifications.
The technical flaw stems from insufficient access controls within the System UI Tuner framework, where the QuickStatusBarHeader component fails to properly validate whether the current user context permits setting modifications. This oversight creates an attack vector where an attacker can physically access a locked device and alter system configurations through the status bar interface. The vulnerability specifically targets the lockscreen environment where normal security restrictions should prevent unauthorized access to system settings, yet the tuner functionality remains accessible even when the device is secured. This represents a direct violation of the principle of least privilege and demonstrates a failure in the Android security model's context awareness mechanisms.
Operationally, this vulnerability poses significant risks to device security as it allows attackers to gain elevated privileges through simple physical access to a locked device. The attack requires only proximity to the device and does not necessitate network connectivity or complex exploitation techniques, making it particularly dangerous in environments where devices may be left unattended or where physical access is possible. An attacker could potentially modify critical system settings such as notification configurations, display preferences, or other interface elements that could be leveraged to create persistent backdoors or facilitate further attacks. The vulnerability also aligns with the ATT&CK framework's privilege escalation tactics, specifically targeting the 'Modify System Image' and 'Access to System Resources' techniques that adversaries use to gain deeper control over affected systems.
The security implications extend beyond simple setting modifications, as the System UI Tuner interface provides access to components that could be manipulated to alter device behavior in ways that compromise security. This vulnerability demonstrates a failure in Android's lockscreen security model where interface elements designed for user convenience inadvertently create security risks. The flaw represents a design oversight in the Android security architecture where the distinction between user interface controls and system security boundaries becomes blurred. Organizations and individuals using affected Android 7.0 devices face potential exposure to unauthorized modifications that could compromise device integrity and user privacy.
Mitigation strategies should focus on immediate patch deployment to address the vulnerability through the 2016-09-01 security update, which properly restricts tuner access on the lockscreen. System administrators should ensure all Android devices are updated to versions that include the security fixes, particularly in enterprise environments where device security is paramount. Additional protective measures include implementing physical security controls to prevent unauthorized access to devices, configuring device policies to limit system UI customization options, and monitoring for unauthorized system modifications. The vulnerability also highlights the importance of security reviews of user interface components, particularly those that provide access to system configuration settings, as demonstrated by the CWE classification for insufficient access control in user interface elements. Organizations should conduct regular security assessments of their mobile device management policies to ensure that interface elements designed for user convenience do not inadvertently create security risks.