CVE-2016-1856 in Safari
Summary
by MITRE
WebKit, as used in Apple iOS before 9.3.2, Safari before 9.1.1, and tvOS before 9.2.1, 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-2016-1854, CVE-2016-1855, and CVE-2016-1857.
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Analysis
by VulDB Data Team • 08/21/2022
This vulnerability affects WebKit rendering engine implementations across multiple Apple platforms including iOS, Safari, and tvOS, representing a critical memory corruption flaw that enables remote code execution. The vulnerability stems from improper handling of crafted web content that leads to memory corruption conditions, allowing attackers to execute arbitrary code on affected systems. WebKit serves as the core rendering engine for Apple's web browsers and applications, making this vulnerability particularly dangerous as it can be exploited through standard web browsing activities without requiring any special privileges or user interaction beyond visiting a malicious website.
The technical flaw manifests as a memory corruption vulnerability that occurs when WebKit processes specially crafted web content, specifically involving the handling of JavaScript objects and memory management operations. This type of vulnerability typically arises from buffer overflows, use-after-free conditions, or improper memory deallocation scenarios within the browser's JavaScript engine. The vulnerability is classified under CWE-125 as an out-of-bounds read condition and may also involve CWE-787 as an out-of-bounds write, both of which are common in browser engine memory management failures. Attackers can leverage this flaw by constructing malicious web pages that trigger the vulnerable code path when rendered by the affected WebKit implementations.
The operational impact of CVE-2016-1856 is severe as it allows remote attackers to achieve arbitrary code execution on targeted systems without user interaction, making it a zero-click exploit. This capability enables attackers to install malware, steal sensitive data, perform man-in-the-middle attacks, or use the compromised system as a pivot point for further network reconnaissance. The vulnerability affects a broad range of Apple devices including iPhones, iPads, Mac computers running affected Safari versions, and Apple TV devices, creating a significant attack surface across Apple's ecosystem. The exploit can be delivered through malicious websites, phishing campaigns, or compromised legitimate websites that serve the malicious content.
Organizations and users should immediately apply the security updates released by Apple as part of iOS 9.3.2, Safari 9.1.1, and tvOS 9.2.1, which address this memory corruption vulnerability through proper bounds checking and memory management improvements. System administrators should also implement network-based protections such as web application firewalls and content filtering solutions to block access to known malicious domains. The vulnerability aligns with attack patterns documented in the MITRE ATT&CK framework under technique T1059 for command and script interpreter and T1071 for application layer protocol, as attackers can use this vulnerability to establish persistent access and execute commands on compromised systems. Additional mitigations include enabling sandboxing features, disabling JavaScript when not required, and maintaining comprehensive network monitoring to detect suspicious web traffic patterns that may indicate exploitation attempts.