CVE-2015-7116 in iOS
Summary
by MITRE
libxml2 in Apple iOS before 9.2, OS X before 10.11.2, and tvOS before 9.1 allows remote attackers to obtain sensitive information or cause a denial of service (memory corruption) via a crafted XML document, a different vulnerability than CVE-2015-7115.
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Analysis
by VulDB Data Team • 11/16/2024
The vulnerability identified as CVE-2015-7116 represents a critical memory corruption issue affecting libxml2, the XML parsing library widely used across Apple's ecosystem including iOS, macOS, and tvOS. This flaw manifests when the affected software processes maliciously crafted XML documents, creating potential vectors for both information disclosure and denial of service attacks. The vulnerability specifically impacts versions of Apple's operating systems prior to the security patches released in iOS 9.2, macOS 10.11.2, and tvOS 9.1, indicating a widespread exposure across multiple platform variants that rely on the same underlying XML processing infrastructure.
The technical nature of this vulnerability stems from improper memory handling within libxml2's XML parser implementation. When processing specially constructed XML documents, the parser fails to properly validate memory allocations and deallocations, leading to memory corruption that can be exploited by remote attackers. This memory corruption typically occurs through buffer overflows or use-after-free conditions that allow attackers to either extract sensitive information from memory or cause the application to crash, resulting in denial of service. The flaw operates at the parser level where XML document structures are interpreted and converted into memory representations, making it particularly dangerous as XML processing is fundamental to numerous applications and system components.
The operational impact of CVE-2015-7116 extends beyond simple system instability, as it provides attackers with potential pathways for information disclosure that could reveal sensitive system data, credentials, or proprietary information stored in memory. The remote exploitation capability means that attackers do not need physical access to devices or local network presence to carry out attacks, making the vulnerability particularly concerning for enterprise environments and users who process untrusted XML content from web services, email attachments, or file downloads. Systems that regularly parse XML documents from external sources become prime targets, as the vulnerability can be triggered through legitimate XML processing operations without requiring user interaction or specific malicious actions beyond crafting the initial XML payload.
Security professionals should consider this vulnerability in the context of the broader ATT&CK framework, where it maps to techniques involving memory corruption and information disclosure within application execution environments. The vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and CWE-122, covering buffer overflow issues, while also demonstrating characteristics of CWE-476, pointer issues, and CWE-119, which encompasses memory corruption vulnerabilities. Organizations should implement immediate mitigation strategies including applying the relevant security patches, deploying network-based protections such as XML filtering rules, and monitoring for suspicious XML processing activities. Additionally, security teams should conduct vulnerability assessments to identify systems running affected versions of libxml2 and establish incident response procedures to address potential exploitation attempts. The vulnerability serves as a reminder of the critical importance of keeping XML processing libraries updated and maintaining robust input validation controls to prevent similar memory corruption issues in other software components.