CVE-2015-5827 in iOS
Summary
by MITRE
WebKit in Apple iOS before 9 allows remote attackers to bypass the Same Origin Policy and obtain an object reference via vectors involving a (1) custom event, (2) message event, or (3) pop state event.
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Analysis
by VulDB Data Team • 11/22/2024
The vulnerability described in CVE-2015-5827 represents a critical security flaw in Apple iOS WebKit implementation that fundamentally undermines the browser's security model. This issue affects iOS versions prior to 9.0 and specifically targets the Same Origin Policy enforcement mechanism that serves as a cornerstone of web security. The Same Origin Policy is a fundamental security principle that prevents scripts from one origin from accessing resources or objects from another origin, thereby protecting users from cross-site scripting attacks and data theft. The flaw allows attackers to circumvent this essential protection through three distinct attack vectors involving custom events, message events, and pop state events, creating a significant window for malicious activities.
The technical nature of this vulnerability stems from improper handling of event propagation and object reference management within WebKit's JavaScript execution environment. When custom events are dispatched, message events are processed, or pop state events are triggered, the browser fails to properly validate the origin of these events before exposing object references to potentially malicious code. This improper validation creates a pathway for attackers to manipulate the event flow and gain access to objects that should remain isolated due to cross-origin restrictions. The vulnerability operates at the intersection of event handling mechanisms and object security boundaries, exploiting a design flaw in how WebKit manages the security context during event processing. This allows attackers to execute code that can access sensitive information or manipulate objects across different origins, effectively breaking down the isolation that browsers maintain between different websites and applications.
The operational impact of CVE-2015-5827 extends far beyond simple privacy violations, as it enables sophisticated attack scenarios that can compromise user data and system integrity. Attackers can leverage this vulnerability to perform cross-site scripting attacks that bypass traditional security controls, potentially accessing cookies, local storage, and other sensitive data from different origins. The attack vectors provide multiple pathways for exploitation, making the vulnerability particularly dangerous as defenders must protect against three distinct attack methods rather than a single entry point. Users of affected iOS versions face elevated risk when visiting malicious websites or clicking on compromised links, as the vulnerability can be exploited through simple web page interactions without requiring any special privileges or user actions beyond normal browsing. This type of vulnerability directly impacts the CIA triad by compromising confidentiality and integrity, as attackers can access and manipulate data across different security domains.
Security mitigations for CVE-2015-5827 primarily focus on updating to iOS 9.0 or later versions where Apple has implemented proper event handling and origin validation mechanisms. System administrators should ensure that all iOS devices within their environment are updated to the latest security patches, as this vulnerability represents a critical threat to mobile web security. Organizations should also implement network monitoring solutions that can detect suspicious web traffic patterns and consider deploying web application firewalls that can help identify and block exploitation attempts. The vulnerability aligns with CWE-284, which addresses improper access control in web applications, and maps to ATT&CK techniques related to privilege escalation and credential access through web-based attacks. Additionally, developers should review their web applications for potential reliance on vulnerable event handling patterns and ensure that proper security measures are in place to prevent exploitation of similar vulnerabilities in other components of their systems.