CVE-2015-4162 in PAN-OS
Summary
by MITRE
XML external entity (XXE) vulnerability in the management interface in PAN-OS before 5.0.16, 6.x before 6.0.8, and 6.1.x before 6.1.4 allows remote authenticated administrators to obtain sensitive information via crafted XML data.
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Analysis
by VulDB Data Team • 04/03/2019
The CVE-2015-4162 vulnerability represents a critical XML external entity processing flaw that affected Palo Alto Networks PAN-OS management interfaces across multiple version ranges. This vulnerability specifically targeted the web-based management console that administrators used to configure and monitor network security policies. The flaw existed in the processing of XML data within the management interface, creating a pathway for unauthorized information disclosure. Attackers could exploit this vulnerability by crafting malicious XML payloads that would trigger the processing of external entities, thereby enabling them to access sensitive system information. The vulnerability was particularly concerning because it required only authenticated administrator access, meaning that an attacker who had already compromised administrative credentials could leverage this weakness to extract additional sensitive data from the system.
The technical implementation of this XXE vulnerability stemmed from insufficient input validation within the PAN-OS management interface. When the system processed XML data containing external entity references, it failed to properly sanitize or restrict the resolution of these entities. This behavior aligns with CWE-611, which categorizes improper restriction of XML external entity references as a fundamental weakness in XML processing. The vulnerability allowed attackers to reference external resources that could be crafted to return system information, including but not limited to configuration files, system logs, and potentially even credential information. The attack vector was particularly insidious because it operated through the legitimate management interface, making it difficult to detect through standard network monitoring. The authentication requirement meant that attackers needed valid administrative credentials, but once obtained, they could use this vulnerability to escalate their information gathering capabilities significantly.
The operational impact of CVE-2015-4162 extended beyond simple information disclosure, as it provided attackers with valuable reconnaissance data that could be used for further attacks. The sensitive information that could be obtained included system configurations, user credentials, network topology details, and potentially other system artifacts that would aid in planning more sophisticated attacks. This vulnerability directly aligned with several techniques described in the MITRE ATT&CK framework under the information gathering phase, specifically targeting the collection of system information and credential dumping capabilities. Organizations that were affected by this vulnerability faced increased risk of subsequent attacks, as the leaked information could be used to bypass security controls, identify system weaknesses, or plan targeted attacks against other systems within the network infrastructure. The impact was particularly severe for organizations that had centralized management interfaces and relied heavily on the administrative web console for day-to-day operations.
The recommended mitigations for this vulnerability involved immediate patching of affected PAN-OS versions to the specified secure releases. Organizations should have upgraded from affected versions to PAN-OS 5.0.16, 6.0.8, or 6.1.4 respectively, which contained the necessary fixes to prevent XML external entity processing attacks. Additionally, network administrators should have implemented additional security controls such as disabling unnecessary XML processing capabilities within the management interface, implementing stricter input validation for XML data, and monitoring for unusual XML processing activities. The vulnerability highlighted the importance of proper XML processing security measures and demonstrated the need for comprehensive security testing of management interfaces. Organizations should have also reviewed their access control policies to ensure that administrative privileges were properly restricted and that least privilege principles were applied to management interface access. The incident underscored the critical importance of maintaining up-to-date security patches and implementing defense-in-depth strategies to protect management interfaces from both external and internal threats.