CVE-2016-1761 in iOS
Summary
by MITRE
libxml2 in Apple iOS before 9.3, OS X before 10.11.4, and watchOS before 2.2 allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via a crafted XML document.
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Analysis
by VulDB Data Team • 11/11/2024
The vulnerability identified as CVE-2016-1761 represents a critical memory corruption flaw within libxml2, the XML parsing library widely deployed across Apple's ecosystem. This vulnerability affects multiple Apple operating systems including iOS versions prior to 9.3, macOS versions before 10.11.4, and watchOS versions before 2.2, demonstrating the widespread impact of the flaw across Apple's product portfolio. The vulnerability stems from insufficient input validation and memory management within the XML parser implementation, creating opportunities for malicious actors to exploit the library's handling of malformed XML documents.
The technical nature of this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and CWE-122, which covers buffer overflow vulnerabilities in heap-based memory allocations. Attackers can craft specially designed XML documents that, when processed by the vulnerable libxml2 library, trigger memory corruption patterns leading to arbitrary code execution or system crashes. The flaw occurs during the parsing process when the library fails to properly validate memory allocations for XML elements, particularly when handling complex or nested XML structures that exceed expected memory boundaries.
From an operational perspective, this vulnerability presents significant risk to Apple device users and organizations relying on Apple products for business operations. The remote exploitation capability means attackers can deliver malicious XML content through various vectors including web pages, email attachments, or file downloads without requiring physical access to target devices. The potential for arbitrary code execution creates opportunities for persistent malware deployment, data exfiltration, and full system compromise. Additionally, the denial of service component can be leveraged to disrupt services or create persistent availability issues for affected systems.
The attack surface for this vulnerability extends beyond simple web browsing to include any application or service that utilizes libxml2 for XML processing, including email clients, web browsers, and enterprise applications. According to ATT&CK framework category T1203, this vulnerability could be exploited as a means to gain initial access or establish persistence within targeted environments. Organizations should prioritize patch management efforts to update affected Apple operating systems to versions containing the necessary security fixes. The remediation process involves upgrading to iOS 9.3, macOS 10.11.4, or watchOS 2.2, respectively, which contain memory safety improvements and input validation enhancements that address the underlying buffer overflow conditions. Security teams should also implement network monitoring to detect potential exploitation attempts and consider implementing XML content filtering as an additional defensive measure.