CVE-2012-1148 in iTunes
Summary
by MITRE
Memory leak in the poolGrow function in expat/lib/xmlparse.c in expat before 2.1.0 allows context-dependent attackers to cause a denial of service (memory consumption) via a large number of crafted XML files that cause improperly-handled reallocation failures when expanding entities.
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Analysis
by VulDB Data Team • 11/24/2022
The vulnerability identified as CVE-2012-1148 represents a critical memory management flaw within the expat XML parser library, a widely-used open source component that processes xml data across numerous applications and systems. This issue specifically affects versions of expat prior to 2.1.0 and stems from improper handling of memory allocation during entity expansion operations. The flaw manifests when the poolGrow function in expat/lib/xmlparse.c fails to properly manage reallocation attempts, leading to progressive memory consumption that can ultimately result in system instability or complete service disruption. The vulnerability operates with context dependency, meaning that attackers must craft specific XML payloads to exploit the weakness effectively.
The technical implementation of this memory leak occurs within the expat library's memory management subsystem where the poolGrow function is responsible for expanding memory pools when processing XML entities. When the parser encounters XML documents containing crafted entities that trigger reallocation failures, the function fails to properly handle these error conditions, resulting in memory fragments that are never properly deallocated. This creates a progressive memory consumption pattern where each processed XML file with malicious content contributes to growing memory usage without adequate cleanup. The vulnerability is particularly insidious because it can be triggered through repeated processing of seemingly benign XML files, making it difficult to detect and prevent through simple input validation alone.
From an operational impact perspective, this vulnerability enables attackers to execute effective denial of service attacks against systems relying on expat for XML processing. The memory consumption pattern can gradually exhaust system resources, leading to application crashes, system slowdowns, or complete service unavailability. Since expat is integrated into numerous applications including web servers, database systems, and enterprise software platforms, the potential attack surface is extensive. The vulnerability can be exploited through various attack vectors including web applications that process user-supplied XML content, email systems processing XML attachments, or any system that parses XML data without proper input sanitization. This makes the impact particularly severe as organizations may unknowingly expose themselves to this vulnerability across multiple layers of their infrastructure.
The mitigation strategy for CVE-2012-1148 requires immediate upgrading of expat libraries to version 2.1.0 or later where the memory leak has been addressed through improved reallocation error handling. Organizations should implement comprehensive patch management procedures to ensure all systems using expat are updated promptly. Additionally, input validation and rate limiting measures should be implemented to reduce the effectiveness of potential exploitation attempts. The vulnerability aligns with CWE-401, which specifically addresses improper handling of memory allocation failures, and represents a classic example of memory leak patterns that can be exploited through resource exhaustion attacks. From an attacker perspective, this vulnerability maps to ATT&CK technique T1499.004, which covers network denial of service attacks through resource exhaustion, making it a significant concern for cybersecurity practitioners responsible for protecting enterprise infrastructure.