CVE-2017-8913 in NetWeaver AS JAVA
Summary
by MITRE
The Visual Composer VC70RUNTIME component in SAP NetWeaver AS JAVA 7.5 allows remote authenticated users to conduct XML External Entity (XXE) attacks via a crafted XML document in a request to irj/servlet/prt/portal/prtroot/com.sap.visualcomposer.BIKit.default, aka SAP Security Note 2386873.
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Analysis
by VulDB Data Team • 10/02/2020
The vulnerability identified as CVE-2017-8913 represents a critical XML External Entity processing flaw within the Visual Composer VC70RUNTIME component of SAP NetWeaver AS JAVA version 7.5. This security weakness exists in the web application's handling of XML data within the specific servlet endpoint irj/servlet/prt/portal/prtroot/com.sap.visualcomposer.BIKit.default. The vulnerability enables remote authenticated attackers to exploit XML External Entity processing mechanisms, which fall under the CWE-611 weakness category related to Improper Restriction of XML External Entity Reference. The attack vector requires an authenticated user to submit a specially crafted XML document through the vulnerable servlet path, making this a significant concern for SAP NetWeaver environments where user authentication is required for access to business intelligence and visualization components.
The technical exploitation of this XXE vulnerability occurs through the improper validation and processing of XML input data within the Visual Composer component. When a crafted XML document is submitted to the vulnerable endpoint, the application fails to properly restrict external entity references, allowing an attacker to manipulate the XML parser to access internal system resources. This weakness enables various attack scenarios including file disclosure, internal network scanning, and potential denial of service conditions. The vulnerability specifically affects the BIKit default servlet path which is part of SAP's business intelligence and visualization framework, making it particularly dangerous for organizations relying on SAP NetWeaver for enterprise reporting and data visualization capabilities. The attack requires authentication but does not require special privileges beyond standard user access, which significantly increases the attack surface and potential impact within enterprise environments.
The operational impact of CVE-2017-8913 extends beyond simple data exposure, as it represents a fundamental flaw in XML processing that could enable attackers to gain unauthorized access to sensitive internal resources. This vulnerability can potentially allow attackers to read local files on the server, perform port scanning of internal networks, or even execute arbitrary code depending on the server configuration and available resources. The attack can be particularly devastating in enterprise environments where SAP NetWeaver systems often serve as central business intelligence platforms containing sensitive corporate data, financial information, and operational metrics. Organizations utilizing this component may face compliance violations, data breaches, and operational disruptions that could affect business continuity and regulatory compliance. The vulnerability also aligns with ATT&CK technique T1059.007 for XML External Entity Processing, which specifically targets the exploitation of XML parsing vulnerabilities to achieve unauthorized access and data exfiltration.
Mitigation strategies for CVE-2017-8913 should prioritize immediate patch application from SAP as the primary remediation measure, addressing the root cause through the official security note 2386873. Organizations should also implement network segmentation and access controls to limit the exposure of vulnerable endpoints, particularly restricting access to the irj/servlet/prt/portal/prtroot/com.sap.visualcomposer.BIKit.default path to only authorized users. Additional protective measures include implementing XML parser configuration changes to disable external entity processing, deploying web application firewalls with rules to detect and block suspicious XML content, and conducting regular vulnerability assessments to identify similar weaknesses in other components. Security monitoring should be enhanced to detect unusual XML processing patterns or unauthorized access attempts to the vulnerable servlet paths. Organizations should also review their authentication mechanisms and implement least privilege principles to minimize the potential impact of successful exploitation, as the vulnerability requires authentication but could provide attackers with elevated access to business intelligence data and system resources within the SAP environment.