CVE-2016-4616 in tvOS
Summary
by MITRE
libxml2 in Apple iOS before 9.3.3, OS X before 10.11.6, iTunes before 12.4.2 on Windows, iCloud before 5.2.1 on Windows, tvOS before 9.2.2, and watchOS before 2.2.2 allows remote attackers to cause a denial of service (memory corruption) or possibly have unspecified other impact via unknown vectors, a different vulnerability than CVE-2016-4614, CVE-2016-4615, and CVE-2016-4619.
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Analysis
by VulDB Data Team • 09/06/2022
The vulnerability identified as CVE-2016-4616 represents a critical memory corruption issue within Apple's libxml2 library implementation across multiple operating systems and applications. This flaw affects iOS versions prior to 9.3.3, macOS versions before 10.11.6, iTunes versions before 12.4.2 on Windows, iCloud versions before 5.2.1 on Windows, tvOS versions before 9.2.2, and watchOS versions before 2.2.2. The vulnerability stems from improper handling of malformed XML data during parsing operations, creating potential pathways for remote attackers to exploit memory corruption conditions that could lead to system instability or arbitrary code execution.
The technical nature of this vulnerability involves memory management failures within the libxml2 XML parser library that Apple integrates into its various software products. When processing malformed or specially crafted XML input, the library fails to properly validate memory allocations and deallocations, leading to buffer overflows, use-after-free conditions, or other memory corruption patterns. These memory corruption issues typically occur during XML document parsing when the parser encounters unexpected or malformed elements, attributes, or encoding structures that it cannot properly handle. The vulnerability's classification aligns with CWE-122, which describes heap-based buffer overflow conditions, and CWE-476, which covers null pointer dereference scenarios that often accompany memory corruption vulnerabilities.
The operational impact of CVE-2016-4616 extends beyond simple denial of service conditions to potentially enable more severe attacks including remote code execution and system compromise. Attackers can leverage this vulnerability by delivering malicious XML content through various attack vectors such as web pages, email attachments, or file sharing protocols that trigger the affected applications to parse the malformed XML data. The memory corruption can result in application crashes, system instability, or in more sophisticated exploitation scenarios, allow attackers to execute arbitrary code with the privileges of the affected application. This vulnerability particularly affects applications that process XML content from untrusted sources, making it a significant concern for web browsers, email clients, and document processing applications that utilize libxml2 for XML parsing operations.
Security professionals should implement multiple layers of mitigation strategies to protect against exploitation of CVE-2016-4616. The primary recommendation involves applying the vendor-provided security updates and patches that address the memory corruption issues in libxml2. Organizations should also implement network-based protections such as web application firewalls and XML validation filters that can detect and block suspicious XML content before it reaches vulnerable applications. Additionally, system administrators should configure applications to limit XML processing capabilities and implement strict input validation controls that prevent parsing of untrusted XML data. The vulnerability's characteristics align with ATT&CK technique T1203, which describes exploitation of software vulnerabilities for privilege escalation and system compromise, making comprehensive patch management and network segmentation critical defensive measures. Organizations should also consider implementing monitoring solutions that can detect anomalous behavior patterns consistent with memory corruption exploitation attempts, as these systems often exhibit specific indicators before complete system compromise occurs.