CVE-2011-0158 in iOS
Summary
by MITRE
MobileSafari in Apple iOS before 4.3 does not properly implement application launching through URL handlers, which allows remote attackers to cause a denial of service (persistent application crash) via crafted JavaScript code.
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Analysis
by VulDB Data Team • 06/16/2017
The vulnerability identified as CVE-2011-0158 resides within Apple iOS versions prior to 4.3, specifically affecting the MobileSafari web browser component. This flaw represents a significant security weakness in the operating system's handling of URL scheme processing and application launching mechanisms. The vulnerability stems from improper implementation of URL handler protocols that govern how iOS applications interact with web-based content and external launch requests. MobileSafari's failure to properly validate and sanitize URL schemes creates an exploitable condition that remote attackers can leverage to disrupt normal application functionality.
The technical implementation of this vulnerability occurs through crafted JavaScript code that manipulates URL scheme handlers within the MobileSafari environment. When a user visits a malicious webpage containing specifically crafted JavaScript, the code can trigger improper application launching sequences that result in persistent crashes. This occurs because the iOS operating system fails to properly validate the parameters and execution context of URL scheme requests, allowing attackers to construct malicious payloads that exploit the underlying implementation flaw. The vulnerability specifically targets the application launching subsystem that processes URL handlers, creating a pathway for denial of service conditions that can persist across multiple application sessions.
The operational impact of CVE-2011-0158 extends beyond simple service disruption to create persistent application instability that affects user experience and system reliability. Users visiting compromised websites face immediate risk of application crashes that can render MobileSafari unusable until the affected application is manually restarted or the device is rebooted. This vulnerability can be exploited in mass deployment scenarios where attackers craft malicious web pages designed to trigger the crash condition across multiple devices simultaneously. The persistent nature of the crashes indicates that the vulnerability affects core system components rather than just individual application processes, potentially creating cascading effects that impact other iOS services and user applications.
This vulnerability aligns with CWE-170, which addresses improper handling of input that can lead to application instability, and demonstrates characteristics consistent with ATT&CK technique T1211, which involves exploitation of application vulnerabilities to cause denial of service conditions. The flaw represents a critical implementation gap in iOS's URL scheme handling architecture that allows attackers to bypass normal security controls through web-based exploitation. Organizations and users should consider this vulnerability as part of broader mobile security assessments, particularly in environments where iOS devices handle sensitive information or critical business functions. The vulnerability's persistence across application sessions indicates a fundamental flaw in iOS's application launching and URL processing architecture that requires comprehensive system-level remediation.
Mitigation strategies for CVE-2011-0158 require immediate implementation of iOS version updates to 4.3 or later, which contain the necessary patches to address the URL handler implementation flaw. System administrators should also implement web content filtering solutions to block access to known malicious domains that may host exploit code targeting this vulnerability. Additionally, user education regarding safe browsing practices and awareness of suspicious web content can help reduce exposure risk. Network monitoring solutions should be configured to detect and alert on unusual URL scheme processing patterns that may indicate exploitation attempts. The vulnerability serves as a reminder of the critical importance of timely security updates and proper input validation in mobile operating system implementations, particularly in handling cross-application communication mechanisms.