CVE-2015-0923 in Ektron CMS
Summary
by MITRE
The ContentBlockEx method in Workarea/ServerControlWS.asmx in Ektron Content Management System (CMS) 8.5 and 8.7 before 8.7sp2 and 9.0 before sp1 allows remote attackers to read arbitrary files via an external entity declaration in conjunction with an entity reference within an XML document named in the xslt parameter, related to an XML External Entity (XXE) issue.
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Analysis
by VulDB Data Team • 11/04/2024
The vulnerability identified as CVE-2015-0923 represents a critical XML External Entity (XXE) flaw within the Ektron Content Management System that affects versions 8.5 and 8.7 prior to 8.7sp2 and 9.0 prior to sp1. This vulnerability exists in the ContentBlockEx method located within the Workarea/ServerControlWS.asmx web service endpoint, making it accessible to remote attackers without authentication. The flaw specifically manifests when the system processes XML documents submitted through the xslt parameter, creating a dangerous attack vector that enables unauthorized file access and system reconnaissance.
The technical implementation of this vulnerability exploits the improper handling of XML input by the Ektron CMS system, where the application fails to properly sanitize or validate external entity declarations within XML documents. When an attacker crafts a malicious XML document containing external entity declarations and references them within the xslt parameter, the system processes these entities without adequate restrictions, allowing the XML parser to resolve external references and access local files on the server. This XXE vulnerability falls under CWE-611, which specifically addresses improper restriction of XML external entity reference, and demonstrates how XML parsing libraries can be manipulated to bypass security controls. The vulnerability enables attackers to perform file disclosure attacks, potentially accessing sensitive system files, configuration data, and database connection strings that are stored locally on the server.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with the ability to escalate their attack and potentially gain deeper system access. Remote attackers can leverage this XXE flaw to read arbitrary files on the target system, including system configuration files, application source code, and potentially sensitive data stored in local repositories. The vulnerability affects the core content management functionality of Ektron CMS, making it particularly dangerous for organizations that rely on this platform for their digital content management. Attackers can use this vulnerability to gather intelligence about the target environment, identify other potential attack vectors, and potentially establish persistence within the compromised system.
Organizations affected by CVE-2015-0923 should immediately apply the vendor-provided patches, specifically upgrading to Ektron CMS 8.7sp2 or 9.0sp1, which contain fixes addressing the XXE vulnerability in the ContentBlockEx method. The mitigation strategy should also include implementing proper XML input validation and sanitization measures, configuring web application firewalls to detect and block suspicious XML content, and conducting comprehensive security assessments of all XML processing components within the application. Additionally, organizations should consider implementing network segmentation to limit access to the affected web service and establish monitoring protocols to detect potential exploitation attempts. This vulnerability aligns with ATT&CK technique T1213.002, which involves data from information repositories, and demonstrates how XXE vulnerabilities can be exploited to extract sensitive data from server-side applications, making it a critical concern for cybersecurity professionals managing enterprise content management systems.