CVE-2019-8779 in iOS
Summary
by MITRE
A logic issue applied the incorrect restrictions. This issue was addressed by updating the logic to apply the correct restrictions. This issue is fixed in iOS 13.1.1 and iPadOS 13.1.1. Third party app extensions may not receive the correct sandbox restrictions.
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Analysis
by VulDB Data Team • 09/15/2020
The vulnerability identified as CVE-2019-8779 represents a logic flaw in iOS and iPadOS that affected the application of sandbox restrictions for third-party app extensions. This issue stems from an improper implementation of access control mechanisms that failed to correctly enforce security boundaries within the operating system's extension architecture. The flaw specifically manifested in how the system handled sandbox policies for app extensions, creating potential pathways for unauthorized access or privilege escalation. The vulnerability was categorized under CWE-284, which addresses improper access control issues, and aligns with ATT&CK technique T1068, which covers local privilege escalation through improper access control mechanisms. The root cause involved a logical error in the code that governs how sandbox restrictions are applied to extension processes, leading to inconsistent enforcement of security policies.
The technical impact of this vulnerability extends beyond simple access control failures as it compromised the fundamental security model of iOS app extensions. When third-party extensions were loaded, the system failed to properly apply the intended sandbox boundaries, potentially allowing extensions to access resources or perform operations that should have been restricted. This logical flaw created a scenario where the security context of app extensions could be bypassed, undermining the isolation mechanisms that protect the operating system from malicious or poorly coded extensions. The vulnerability was particularly concerning because it affected the core sandboxing architecture that governs how extensions interact with system resources, potentially enabling attackers to exploit this weakness to gain elevated privileges or access sensitive data through compromised extensions.
The operational impact of CVE-2019-8779 was significant for both end users and system administrators, as it represented a potential vector for persistent threats targeting iOS devices. The vulnerability affected all versions of iOS and iPadOS prior to 13.1.1, leaving millions of devices exposed to potential exploitation. Organizations that relied on iOS for business operations faced increased risk of data breaches or system compromise through malicious extensions, particularly in environments where third-party applications were heavily utilized. The fix implemented by Apple addressed the core logic issue by correcting the restriction application process and ensuring that proper sandbox boundaries were enforced for all app extensions. This remediation aligned with security best practices outlined in the OWASP Mobile Top 10 and iOS security guidelines, emphasizing the importance of proper access control implementation in mobile operating systems.
Mitigation strategies for this vulnerability centered on immediate system updates to iOS 13.1.1 or iPadOS 13.1.1, as this represented the primary and most effective solution to address the underlying logic flaw. Security teams were advised to prioritize deployment of these updates across all managed iOS devices to eliminate the risk of exploitation. Additionally, organizations should implement monitoring for suspicious extension behavior and review extension permissions to ensure that only necessary third-party applications were installed. The vulnerability highlighted the importance of continuous security assessment of operating system components and demonstrated how seemingly minor logic errors in access control implementation could create significant security risks. System administrators should also consider implementing additional security controls such as mobile device management policies that restrict extension installation and monitor for unauthorized application modifications to provide defense-in-depth against similar vulnerabilities.