CVE-2013-2156 in XML Security for C++
Summary
by MITRE
Heap-based buffer overflow in the Exclusive Canonicalization functionality (xsec/canon/XSECC14n20010315.cpp) in Apache Santuario XML Security for C++ (aka xml-security-c) before 1.7.1 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via a crafted PrefixList attribute.
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Analysis
by VulDB Data Team • 01/04/2022
The vulnerability CVE-2013-2156 represents a critical heap-based buffer overflow within Apache Santuario XML Security for C++ library, specifically affecting the Exclusive Canonicalization functionality. This flaw exists in the xsec/canon/XSECC14n20010315.cpp source file and impacts versions prior to 1.7.1. The vulnerability arises from inadequate input validation when processing the PrefixList attribute during XML canonicalization operations, creating a condition where attacker-controlled data can overwrite adjacent memory regions in the heap. The issue manifests as a heap-based buffer overflow, which is classified under CWE-121 as a heap-based buffer overflow vulnerability, making it particularly dangerous due to the potential for both denial of service and arbitrary code execution.
The technical exploitation of this vulnerability occurs when a malicious XML document contains a crafted PrefixList attribute that exceeds the allocated buffer size during the canonicalization process. The Exclusive Canonicalization algorithm, which is part of the XML Signature specification, processes XML documents to produce a deterministic canonical form that can be signed and verified. When the library processes this malformed PrefixList attribute without proper bounds checking, it writes data beyond the allocated memory boundaries, leading to memory corruption that can result in program termination or unpredictable behavior. This vulnerability directly maps to the ATT&CK technique T1203 - Exploitation for Client Execution, as it allows for remote code execution through manipulation of XML processing libraries.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as the heap corruption can potentially be leveraged to execute arbitrary code on the target system. Attackers can craft malicious XML documents containing specially formatted PrefixList attributes that trigger the buffer overflow when processed by applications using the affected Apache Santuario library. This makes the vulnerability particularly dangerous in environments where XML processing is common, such as web applications, enterprise systems, and security tools that rely on XML signature validation. The vulnerability affects any application that utilizes the xml-security-c library for XML signature processing, including but not limited to web services, enterprise security frameworks, and document processing systems.
Organizations should immediately implement mitigation strategies including upgrading to Apache Santuario XML Security for C++ version 1.7.1 or later, which contains the necessary patches to address this vulnerability. Additionally, input validation should be strengthened at application level to sanitize XML documents before processing, particularly when dealing with user-supplied XML content. Network segmentation and access controls should be implemented to limit exposure of systems that process XML documents, while monitoring systems should be configured to detect unusual XML processing patterns that might indicate exploitation attempts. The vulnerability also underscores the importance of regular security assessments and vulnerability management processes to identify and remediate similar issues in third-party libraries and dependencies.