CVE-2017-7376 in libxml2
Summary
by MITRE
Buffer overflow in libxml2 allows remote attackers to execute arbitrary code by leveraging an incorrect limit for port values when handling redirects.
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Analysis
by VulDB Data Team • 02/08/2023
The vulnerability identified as CVE-2017-7376 represents a critical buffer overflow flaw within the libxml2 library, a widely deployed XML parsing component that forms the backbone of numerous applications across diverse computing environments. This vulnerability specifically manifests when the library processes HTTP redirects, creating a scenario where remote attackers can exploit malformed port value handling to trigger arbitrary code execution. The flaw resides in the library's improper validation of port limits during redirect processing, allowing attackers to craft malicious XML content that, when parsed, overflows buffer boundaries and potentially compromises system integrity.
The technical implementation of this vulnerability stems from insufficient input validation within the libxml2 parsing engine's redirect handling mechanism. When processing XML documents containing HTTP redirect references, the library fails to properly enforce bounds checking on port values, particularly when these values exceed expected ranges. This oversight creates a condition where attacker-controlled data can overflow predetermined buffer sizes, potentially overwriting adjacent memory regions and enabling code execution. The vulnerability is particularly dangerous because it can be triggered through standard XML parsing operations, making it accessible to attackers who can influence XML content through various attack vectors such as web applications, file uploads, or network communications.
The operational impact of CVE-2017-7376 extends across numerous software ecosystems that rely on libxml2 for XML processing, including but not limited to web servers, content management systems, database applications, and security tools. Attackers exploiting this vulnerability can achieve remote code execution with the privileges of the affected application, potentially leading to full system compromise, data exfiltration, or establishment of persistent backdoors. The vulnerability's remote exploitability means that attackers do not require local access or special privileges to initiate attacks, making it particularly concerning for internet-facing applications and services. The flaw can be leveraged in conjunction with other techniques to escalate privileges or move laterally within compromised networks, amplifying its overall threat potential.
Mitigation strategies for CVE-2017-7376 should prioritize immediate patching of affected libxml2 versions, with administrators monitoring for updates from their respective software vendors and operating system distributors. Organizations should implement network segmentation and access controls to limit exposure of systems that process untrusted XML content, while also deploying intrusion detection systems to monitor for potential exploitation attempts. The vulnerability aligns with CWE-121, which addresses stack-based buffer overflow conditions, and can be mapped to ATT&CK technique T1059.007 for remote code execution through XML parsing. Security teams should also consider implementing application whitelisting policies, input validation measures, and regular vulnerability assessments to identify and remediate similar issues within their technology stack, ensuring comprehensive protection against both current and emerging threats targeting XML processing components.