CVE-2015-7326 in Webdav
Summary
by MITRE
XML External Entity (XXE) vulnerability in Milton Webdav before 2.7.0.3.
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Analysis
by VulDB Data Team • 06/22/2024
The CVE-2015-7326 vulnerability represents a critical XML External Entity processing flaw affecting the Milton Webdav server software prior to version 2.7.0.3. This vulnerability falls under the broader category of XML external entity injection attacks that have plagued web applications for over a decade. The flaw allows attackers to manipulate how XML documents are processed by the application, potentially enabling them to access internal resources, perform server-side request forgery attacks, or even execute arbitrary code depending on the underlying system configuration. The vulnerability specifically affects the XML parsing functionality within the Milton Webdav implementation, which is commonly used for web-based file sharing and collaboration platforms.
The technical root cause of this vulnerability stems from insufficient input validation and sanitization within the XML processing pipeline of the Milton Webdav server. When the application receives XML data containing external entity declarations, it fails to properly restrict or disable the processing of external references. This behavior aligns with CWE-611, which categorizes improper restriction of XML external entity references as a fundamental weakness in application security. The vulnerability allows an attacker to craft malicious XML payloads that reference external resources, potentially leading to information disclosure, denial of service conditions, or remote code execution depending on the server environment and configuration. The flaw exists because the XML parser used by the application does not enforce secure parsing practices, particularly in disabling external entity resolution by default.
The operational impact of CVE-2015-7326 extends beyond simple data exposure, as it can enable sophisticated attack vectors that leverage the Webdav protocol's functionality. Attackers can exploit this vulnerability to perform server-side request forgery attacks by referencing external URLs that may contain malicious content or attempt to access internal network resources. This capability significantly expands the attack surface for organizations using affected Milton Webdav implementations, particularly in environments where the Webdav server serves as a gateway to internal systems. The vulnerability can also facilitate denial of service attacks by causing the server to consume excessive resources while processing malicious XML entities. Organizations may face compliance issues with security frameworks such as the Payment Card Industry Data Security Standard (PCI DSS) and the National Institute of Standards and Technology (NIST) cybersecurity guidelines, which require proper input validation and secure coding practices to prevent such vulnerabilities.
Mitigation strategies for CVE-2015-7326 should prioritize immediate patching of affected Milton Webdav installations to version 2.7.0.3 or later, which contains the necessary security fixes. Organizations should also implement proper XML parser configuration to disable external entity resolution entirely, following the principle of least privilege in security implementations. Network segmentation and firewall rules can help limit the exposure of Webdav services to untrusted networks, while web application firewalls may provide additional protection layers. Security teams should conduct thorough vulnerability assessments to identify all instances of the affected software and ensure proper input validation is implemented across all XML processing components. The vulnerability also highlights the importance of adhering to the ATT&CK framework's defense-in-depth strategies, particularly the techniques related to input validation and secure coding practices. Regular security testing and code reviews should be implemented to prevent similar issues in future development cycles, while also ensuring compliance with industry standards such as OWASP Top Ten and ISO 27001 security requirements. Organizations should also consider implementing automated monitoring solutions to detect potential exploitation attempts and maintain detailed audit logs for forensic analysis purposes.