CVE-2015-2812 in NetWeaver
Summary
by MITRE
XML external entity (XXE) vulnerability in XMLValidationComponent in SAP NetWeaver Portal 7.31.201109172004 allows remote attackers to send requests to intranet servers via crafted XML, aka SAP Security Note 2093966.
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Analysis
by VulDB Data Team • 05/02/2022
The XML external entity vulnerability identified as CVE-2015-2812 represents a critical security flaw within SAP NetWeaver Portal version 7.31.201109172004 that exposes organizations to significant remote attack vectors. This vulnerability specifically affects the XMLValidationComponent which processes XML data inputs within the portal environment. The flaw enables malicious actors to craft specially formatted XML requests that can trigger unintended network communications, effectively allowing attackers to bypass normal network segmentation controls and access internal systems that should otherwise remain isolated from external threats. The vulnerability operates through the improper handling of external entity references during XML parsing operations, creating a pathway for attackers to leverage the portal's XML processing capabilities as an attack vector against internal infrastructure.
The technical implementation of this vulnerability stems from inadequate input validation and XML parser configuration within the SAP NetWeaver Portal framework. When the XMLValidationComponent processes malformed XML containing external entity declarations, it fails to properly restrict access to internal network resources. This behavior aligns with CWE-611, which classifies improper restriction of XML external entity references as a fundamental weakness in web application security. The vulnerability permits attackers to construct XML payloads that reference external entities hosted on internal servers, enabling them to send requests to intranet services and potentially exfiltrate information or perform unauthorized operations against internal systems. The attack mechanism exploits the default XML parser behavior that automatically resolves external entity references without proper sanitization, creating an attack surface that extends beyond the intended network boundaries.
The operational impact of this vulnerability extends beyond simple data exposure, as it fundamentally compromises the network security posture of affected organizations. Remote attackers can leverage this vulnerability to perform internal reconnaissance, identify vulnerable services, and potentially escalate privileges within the internal network infrastructure. The attack scenario typically involves crafting XML requests that reference internal resources, allowing the vulnerable system to make outbound connections to internal servers that would normally be protected by firewalls and network segmentation controls. This capability directly violates the principle of least privilege and network isolation that security professionals rely upon to protect critical internal systems. The vulnerability also creates opportunities for attackers to perform server-side request forgery attacks, potentially enabling them to access sensitive internal applications and databases that are not directly exposed to the internet. Organizations using SAP NetWeaver Portal are particularly at risk as this vulnerability can be exploited without requiring any authentication or privileged access to the portal itself.
Mitigation strategies for CVE-2015-2812 must address both immediate remediation and long-term architectural improvements to prevent similar vulnerabilities from emerging in the future. Organizations should implement immediate patches provided by SAP in accordance with SAP Security Note 2093966, which specifically addresses this XXE vulnerability through updated XML processing components. Network-level protections should include implementing strict firewall rules that prevent outbound connections from the SAP portal to internal servers, combined with proper XML parser configuration that disables external entity resolution. The implementation of proper input validation and sanitization processes becomes critical, ensuring that all XML processing operations are configured to reject external entity references. Additionally, organizations should consider implementing web application firewalls and security monitoring solutions that can detect and prevent suspicious XML processing patterns. This vulnerability highlights the importance of following secure coding practices and adhering to established security frameworks such as the OWASP Top Ten and NIST cybersecurity guidelines. The attack vector described in this vulnerability aligns with ATT&CK technique T1071.004, which covers application layer protocol: xml file transfer, demonstrating how attackers can leverage XML processing capabilities to establish persistent access to internal systems. Organizations should also implement comprehensive security awareness training for developers to prevent similar issues in custom applications and ensure proper XML handling practices are maintained throughout the software development lifecycle.