CVE-2016-4731 in iOS
Summary
by MITRE
WebKit in Apple iOS before 10 and Safari before 10 allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted web site, a different vulnerability than CVE-2016-4729.
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Analysis
by VulDB Data Team • 09/20/2022
The vulnerability identified as CVE-2016-4731 represents a critical memory corruption flaw within Apple WebKit engine that affected iOS versions prior to 10.0 and Safari versions before 10.0. This vulnerability resides in the core rendering engine that powers web browsing on Apple devices, making it a prime target for attackers seeking to compromise user systems through malicious web content. The flaw manifests when WebKit processes specially crafted web pages, creating conditions that can lead to arbitrary code execution or system-wide denial of service. The vulnerability operates independently from CVE-2016-4729, indicating that attackers could leverage different attack vectors to achieve similar outcomes, though the underlying technical mechanisms differ.
The technical nature of this vulnerability stems from improper memory handling within WebKit's JavaScript engine and rendering components. Attackers can construct malicious web pages that trigger buffer overflows, use-after-free conditions, or other memory corruption scenarios when the browser attempts to render or execute the crafted content. These memory corruption issues typically occur during the processing of complex web elements such as JavaScript objects, DOM manipulations, or multimedia content. The flaw exploits weaknesses in memory management and input validation mechanisms that should prevent malformed data from corrupting the browser's memory space. According to CWE classification, this vulnerability aligns with CWE-125, which covers out-of-bounds read conditions, and CWE-787, which addresses out-of-bounds write operations, both of which are common precursors to arbitrary code execution in web browsers.
The operational impact of CVE-2016-4731 extends beyond simple exploitation as it provides attackers with persistent access to user systems through seemingly benign web browsing activities. Users could be compromised simply by visiting malicious websites, making this vulnerability particularly dangerous in phishing campaigns or exploit delivery scenarios. The memory corruption nature of the flaw means that successful exploitation could result in complete system compromise, allowing attackers to execute arbitrary code with the privileges of the web browser process. This could enable data exfiltration, persistent backdoor installation, or further escalation to full system control. The vulnerability's presence in both iOS and Safari applications creates a wide attack surface, as these platforms are widely used for web browsing and often contain sensitive user data.
Mitigation strategies for CVE-2016-4731 primarily focus on immediate system updates and security hardening measures. Apple's release of iOS 10.0 and Safari 10.0 patches addressed the underlying memory corruption issues through improved memory management and input validation. Organizations should implement comprehensive patch management policies to ensure all affected systems receive updates promptly. Network security controls including web proxies, content filtering systems, and intrusion detection systems can provide additional layers of protection by blocking access to known malicious domains. Browser hardening techniques such as sandboxing, disabling unnecessary browser features, and implementing strict content security policies can reduce the attack surface. From an ATT&CK framework perspective, this vulnerability maps to techniques involving exploitation of known vulnerabilities and privilege escalation, requiring defensive measures that align with tactics such as defense evasion and execution. Regular security assessments and user awareness training should also be implemented to reduce the risk of successful exploitation through social engineering or targeted attacks.