CVE-2015-2811 in NetWeaver
Summary
by MITRE
XML external entity (XXE) vulnerability in ReportXmlViewer in SAP NetWeaver Portal 7.31.201109172004 allows remote attackers to send requests to intranet servers via crafted XML, aka SAP Security Note 2111939.
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Analysis
by VulDB Data Team • 05/02/2022
The vulnerability identified as CVE-2015-2811 represents a critical XML external entity injection flaw within SAP NetWeaver Portal version 7.31.201109172004. This weakness specifically affects the ReportXmlViewer component, which processes XML data for report generation and display purposes. The vulnerability stems from insufficient input validation and sanitization of XML content, allowing malicious actors to exploit the system's XML parser to make unauthorized requests to internal network resources. The issue is categorized under CWE-611, which specifically addresses improper restriction of XML external entity references, making it a well-documented and severe class of vulnerability affecting many enterprise applications.
The technical exploitation of this XXE vulnerability enables remote attackers to perform server-side request forgery attacks against internal systems that are typically protected by firewalls and network segmentation. When the ReportXmlViewer processes crafted XML input containing external entity declarations, the XML parser resolves these entities by making HTTP requests to specified URLs, potentially allowing attackers to access internal services, databases, or other network resources that would normally be inaccessible from the internet. This creates a significant attack surface where intranet servers can be targeted through the vulnerable portal interface, effectively bypassing traditional network security controls.
From an operational impact perspective, this vulnerability poses severe risks to enterprise security infrastructure, particularly in environments where SAP NetWeaver Portal serves as a central integration point for business applications. The vulnerability allows attackers to potentially discover internal network topology, access sensitive data stored in internal databases, or even escalate privileges by leveraging access to internal services. The attack vector is particularly dangerous because it requires minimal privileges to exploit and can be executed through standard web browser interactions, making it difficult to detect and prevent through traditional network monitoring approaches. This vulnerability directly relates to ATT&CK technique T1190, which covers exploitation of remote services, and T1071.004, covering application layer protocol usage.
Organizations affected by CVE-2015-2811 should implement immediate mitigations including applying the relevant SAP security note 2111939, which provides specific patches and configuration changes to address the XXE vulnerability. Additional protective measures should include implementing strict XML input validation, disabling external entity resolution in XML parsers, and configuring network firewalls to restrict access to internal services from the portal server. The solution also involves updating the SAP NetWeaver Portal to supported versions that have addressed this vulnerability, as well as implementing comprehensive monitoring for suspicious XML processing activities. Organizations should also consider implementing web application firewalls and regular security assessments to prevent similar vulnerabilities from being introduced in the future, particularly focusing on input validation and secure coding practices that align with OWASP Top 10 and NIST cybersecurity frameworks.