CVE-2015-1092 in Watch OS
Summary
by MITRE
NSXMLParser in Foundation in Apple iOS before 8.3 and Apple TV before 7.2 allows remote attackers to read arbitrary files via an external entity declaration in conjunction with an entity reference, related to an XML External Entity (XXE) issue.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 05/18/2022
The vulnerability identified as CVE-2015-1092 represents a critical XML External Entity (XXE) flaw within Apple's NSXMLParser implementation in the Foundation framework. This weakness affects iOS versions prior to 8.3 and Apple TV versions prior to 7.2, creating a significant security risk that enables remote attackers to exploit the system's XML parsing capabilities. The vulnerability stems from insufficient input validation and improper handling of external entity declarations within the XML processing pipeline, allowing malicious actors to manipulate the parsing behavior through crafted XML documents.
The technical flaw manifests when NSXMLParser encounters external entity declarations within XML documents and subsequently processes entity references without adequate restrictions. Attackers can construct malicious XML payloads that declare external entities pointing to local files on the target system, then reference these entities within the document structure. When the parser processes such documents, it automatically resolves these external references, potentially exposing sensitive system files, configuration data, or user information to unauthorized parties. This vulnerability operates at the core of XML processing mechanisms and demonstrates a classic XXE attack pattern that has been documented across numerous platforms and frameworks.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with potential access to arbitrary file systems through the XML parsing interface. Remote adversaries can leverage this weakness to read system files, configuration parameters, or user data without requiring authentication or privileged access. The attack vector is particularly concerning because it can be executed through various communication channels that utilize XML parsing, including web services, file uploads, or network communications that process XML data. This capability undermines the fundamental security boundaries of the affected systems and creates opportunities for further exploitation or lateral movement within compromised environments.
Organizations and system administrators should prioritize immediate patching of affected Apple devices to address this vulnerability, as the XXE flaw represents a persistent threat that can be exploited without user interaction. The remediation strategy should include updating to iOS 8.3 or later versions and Apple TV 7.2 or later, which contain the necessary security fixes for NSXMLParser's external entity handling. Additionally, implementing proper input validation and XML parser configuration settings can provide additional defense-in-depth measures. Security teams should monitor for potential exploitation attempts and consider deploying network intrusion detection systems to identify suspicious XML processing activities. This vulnerability aligns with CWE-611 (Improper Restriction of XML External Entity Reference) and maps to ATT&CK technique T1213.002 (Data from Information Repositories) within the adversary tactics and techniques framework.