CVE-2018-4247 in iOS
Summary
by MITRE
An issue was discovered in certain Apple products. iOS before 11.4 is affected. Safari before 11.1.1 is affected. The issue involves the "Safari" component. It allows remote attackers to cause a denial of service (persistent Safari outage) via a crafted web site.
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Analysis
by VulDB Data Team • 03/21/2023
This vulnerability resides within Apple's Safari web browser component affecting iOS versions prior to 11.4 and Safari versions before 11.1.1. The flaw represents a persistent denial of service condition that can be triggered through maliciously crafted web content, potentially leading to complete browser outages that require manual intervention to resolve. The vulnerability demonstrates characteristics consistent with a denial of service attack pattern where an attacker can manipulate browser behavior to create sustained operational disruptions. This issue affects the core web rendering engine of Safari and represents a fundamental breakdown in the browser's ability to handle malformed or specially crafted web content without crashing or becoming unresponsive. The vulnerability's impact extends beyond simple browser interruption as it creates persistent outages that can significantly impact user productivity and system availability. The technical nature of this flaw suggests an issue within memory management or resource handling within Safari's web engine, where malformed content can cause the browser process to consume excessive resources or enter an unrecoverable state. This vulnerability aligns with CWE-400 which categorizes improper resource management and CWE-119 which addresses memory safety issues. From an operational perspective, this vulnerability presents a significant risk to users who rely on Safari for daily web browsing activities, as the persistent nature of the outage means that users cannot simply navigate away from the malicious site to recover. The attack vector requires remote exploitation through web content, making it particularly dangerous as users can be affected simply by visiting compromised websites or clicking on malicious links. The vulnerability demonstrates the importance of timely patch management in mobile operating systems where browser components serve as critical user interfaces. Security researchers have identified this issue as a persistent denial of service condition that can be exploited across multiple platforms and user scenarios. The vulnerability's classification as a remote attack vector means that no user interaction beyond visiting a malicious website is required for exploitation. This flaw represents a gap in Safari's input validation and resource handling mechanisms that can be exploited to create sustained browser outages. The impact on user experience is significant as the browser becomes completely unresponsive and requires manual restart of the Safari process or system reboot to restore normal functionality. From a threat modeling perspective, this vulnerability enables attackers to create persistent disruptions that can be particularly effective in targeted attacks against specific users or organizations. The vulnerability's exploitation can be automated and does not require specialized technical knowledge from the attacker, making it a particularly concerning security issue for widespread deployment. The technical implementation of the flaw suggests an issue within Safari's JavaScript engine or rendering pipeline where malformed content can cause the browser to enter a continuous crash loop. This vulnerability type is categorized under ATT&CK technique T1499 which covers denial of service attacks and represents a critical weakness in Apple's security architecture for web browser components. The persistence of the denial of service condition indicates that the browser's recovery mechanisms are insufficient to handle the crafted malicious content. The vulnerability demonstrates how seemingly minor flaws in web rendering engines can create significant operational impacts that affect user productivity and system reliability. The issue highlights the importance of robust input validation and resource management in web browser implementations to prevent malicious content from causing sustained service disruptions. This vulnerability represents a failure in Safari's defensive programming and error handling capabilities, where the browser cannot gracefully handle malformed web content without entering a persistent failure state. The attack scenario involves an attacker hosting malicious web content that when loaded in Safari triggers the vulnerability, causing the browser to become unresponsive and remain in that state until manual intervention occurs. The vulnerability's potential for widespread impact is significant given Safari's user base and the persistent nature of the service disruption it creates. Security professionals should note that this vulnerability represents a critical area for patch management and user awareness campaigns, particularly in enterprise environments where browser stability is essential for business operations. The technical analysis confirms that this vulnerability is not merely a temporary crash but rather a persistent state that requires specific recovery procedures to restore normal browser functionality. This flaw exemplifies the ongoing challenges in web browser security where complex rendering engines can contain vulnerabilities that create sustained operational impacts. The vulnerability underscores the importance of regular security updates and the risks associated with outdated browser versions in maintaining secure computing environments.