CVE-2012-1147 in iTunes
Summary
by MITRE
readfilemap.c in expat before 2.1.0 allows context-dependent attackers to cause a denial of service (file descriptor consumption) via a large number of crafted XML files.
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Analysis
by VulDB Data Team • 11/24/2022
The vulnerability identified as CVE-2012-1147 resides within the expat XML parser library, specifically in the readfilemap.c component that handles file mapping operations. This issue affects expat versions prior to 2.1.0 and represents a significant security concern that can be exploited by context-dependent attackers to execute denial of service attacks. The flaw manifests when the parser processes a large number of crafted XML files, leading to excessive consumption of file descriptors and ultimately system resource exhaustion.
The technical root cause of this vulnerability stems from inadequate resource management within the XML parsing process. When expat encounters multiple XML files, the readfilemap.c module fails to properly close or release file descriptors associated with previously processed files. This results in a gradual accumulation of open file handles that can eventually exhaust the system's available file descriptor limit. The vulnerability is particularly dangerous because it can be triggered through legitimate XML parsing operations, making it difficult to distinguish between normal usage and malicious exploitation attempts. The context-dependent nature of this attack means that the impact varies based on system configuration, available resources, and the specific XML content being processed.
The operational impact of CVE-2012-1147 extends beyond simple service disruption to potentially compromise entire system stability. When file descriptors become exhausted, applications relying on expat for XML processing may crash or become unresponsive, leading to cascading failures in dependent services. This vulnerability particularly affects web applications, enterprise systems, and any software that processes external XML data feeds. The attack vector is especially concerning in environments where XML processing is frequent or automated, as the resource exhaustion can occur gradually over time without immediate detection. System administrators may observe performance degradation before full system failure, making this vulnerability particularly insidious.
Organizations should implement immediate mitigation strategies including upgrading to expat version 2.1.0 or later, which contains the necessary patches to address the file descriptor leak. Additionally, deploying input validation mechanisms to limit the number of XML files processed in single sessions can help reduce exposure. System monitoring should be enhanced to track file descriptor usage patterns and alert on unusual increases that may indicate exploitation attempts. The vulnerability aligns with CWE-404, which addresses improper resource shutdown or release, and maps to ATT&CK technique T1499.001 for network denial of service attacks. Regular security assessments and vulnerability scanning should include checks for expat versions to ensure proper patch management and prevent exploitation of this and similar resource exhaustion vulnerabilities.