CVE-2019-8711 in iOS
Summary
by MITRE
A logic issue existed with the display of notification previews. This issue was addressed with improved validation. This issue is fixed in iOS 13. Notification previews may show on Bluetooth accessories even when previews are disabled.
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Analysis
by VulDB Data Team • 09/09/2020
The vulnerability identified as CVE-2019-8711 represents a logic flaw in iOS notification handling mechanisms that specifically affects how notification previews are displayed on Bluetooth accessories. This issue stems from inadequate validation processes within the operating system's notification subsystem, creating a scenario where user preferences regarding notification privacy are bypassed. The flaw exists in the iOS 13 operating system and demonstrates a failure in proper access control validation for notification display settings. The vulnerability allows notification previews to appear on Bluetooth peripheral devices even when users have explicitly disabled this functionality through system settings, creating an unintended disclosure of information.
The technical implementation of this vulnerability involves the notification preview system failing to properly validate user configuration settings before displaying content on external Bluetooth accessories. This represents a violation of the principle of least privilege and proper access control enforcement, where the system does not adequately respect user-defined privacy preferences. The issue manifests as a logic error in the notification processing pipeline where the system does not properly check whether notification previews are enabled or disabled for Bluetooth devices. This flaw falls under the category of improper validation of system settings, which aligns with CWE-20 validation of input and configuration data. The vulnerability is classified as a privilege escalation issue in the context of notification privacy, where unauthorized information disclosure occurs due to improper access control validation.
The operational impact of this vulnerability extends beyond simple privacy concerns to potentially expose sensitive information to unauthorized parties through Bluetooth connections. When notification previews appear on accessories such as wireless headphones, smartwatches, or car audio systems, users may inadvertently disclose personal information, messages, or other sensitive data that they intended to keep private. This creates a significant risk for users in environments where Bluetooth devices are commonly used, such as public transportation, offices, or private spaces. The vulnerability directly impacts the security posture of iOS devices by undermining user expectations of privacy control and potentially enabling social engineering attacks or information gathering by malicious actors who can access Bluetooth peripherals. The issue represents a failure in the security model of the notification system and affects the integrity of user privacy controls.
Mitigation strategies for this vulnerability should focus on implementing proper validation checks within the notification system and ensuring that user preferences are consistently enforced across all device interfaces. System administrators and users should update to iOS 13 or later versions where the vulnerability has been addressed through improved validation mechanisms. Organizations should conduct security assessments of their iOS device management policies to ensure proper enforcement of notification settings and consider additional monitoring for unauthorized information disclosure. The fix implemented by Apple addresses the core logic flaw by strengthening the validation process for notification preview settings, ensuring that user preferences regarding Bluetooth accessory notifications are properly respected. This aligns with ATT&CK technique T1566 which involves credential access through privilege escalation and information gathering through improper access control validation. The remediation process involves updating to patched versions and verifying that notification settings are properly enforced across all device interfaces including Bluetooth peripherals.