CVE-2016-4615 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-2016-4616, and CVE-2016-4619.
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Analysis
by VulDB Data Team • 09/06/2022
The vulnerability identified as CVE-2016-4615 represents a critical memory corruption issue within libxml2, a widely deployed XML parsing library that forms the backbone of numerous Apple operating systems and applications. This flaw exists across multiple Apple platforms including iOS, macOS, tvOS, and watchOS, as well as Windows versions of iTunes and iCloud. The vulnerability manifests through unknown vectors that differ from related CVEs, indicating a distinct attack surface that requires careful analysis of the underlying XML processing mechanisms. The affected versions demonstrate the widespread nature of this issue, with iOS before 9.3.3, macOS before 10.11.6, and various other Apple products all susceptible to exploitation.
The technical implementation of this vulnerability stems from improper handling of malformed XML data within the libxml2 library. When processing specially crafted XML documents, the library fails to properly validate memory allocations and deallocations, leading to memory corruption that can result in arbitrary code execution or system instability. This type of vulnerability typically falls under CWE-125, which describes out-of-bounds read conditions, or CWE-787, which covers out-of-bounds write operations. The memory corruption occurs during the parsing process when the library attempts to handle malformed input structures that exceed expected boundaries or contain invalid memory references.
The operational impact of CVE-2016-4615 extends beyond simple denial of service, as the memory corruption can potentially enable remote attackers to execute arbitrary code on affected systems. This represents a significant escalation from basic service disruption to full system compromise, particularly when considering that libxml2 is used extensively throughout Apple's ecosystem for parsing configuration files, web content, and various data interchange formats. Attackers could leverage this vulnerability through web-based attacks, email attachments, or any vector that delivers malicious XML content to an affected system, making it particularly dangerous in enterprise environments where such content might be encountered during routine operations.
The exploitation of this vulnerability aligns with techniques described in the MITRE ATT&CK framework under the T1059 category for command and control communication, as well as T1203 for legitimate program execution. The memory corruption aspect particularly relates to T1068 which covers local privilege escalation and T1190 which covers exploit public-facing application. Organizations should implement immediate mitigation strategies including patching affected systems to the latest available versions, as well as network-based filtering to prevent malicious XML content from reaching vulnerable systems. Additionally, monitoring for unusual memory allocation patterns and system instability could serve as early warning indicators of attempted exploitation.
Security teams should prioritize patch management for all affected Apple platforms and applications, with particular attention to the specific version numbers mentioned in the vulnerability description. The remediation process should include comprehensive testing of patched systems to ensure that the vulnerability is properly addressed without introducing regressions in functionality. Organizations utilizing Apple products in enterprise environments should also consider implementing additional security controls such as sandboxing mechanisms and network segmentation to limit the potential impact of successful exploitation attempts. The vulnerability demonstrates the critical importance of maintaining up-to-date security patches across all system components, particularly those that handle external data processing and parsing functions.