CVE-2017-11457 in NetWeaver AS JAVA
Summary
by MITRE
XML external entity (XXE) vulnerability in com.sap.km.cm.ice in SAP NetWeaver AS JAVA 7.5 allows remote authenticated users to read arbitrary files or conduct server-side request forgery (SSRF) attacks via a crafted DTD in an XML request, aka SAP Security Note 2387249.
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Analysis
by VulDB Data Team • 01/06/2021
The vulnerability CVE-2017-11457 represents a critical XML external entity (XXE) flaw located within the com.sap.km.cm.ice component of SAP NetWeaver AS JAVA version 7.5. This security weakness falls under the CWE-611 category, specifically addressing improper restriction of XML external entity reference, which is a well-documented vulnerability pattern in software security. The flaw enables malicious actors to manipulate XML processing mechanisms and exploit the system's handling of external entities, creating a pathway for unauthorized data access and potentially more severe attack vectors. The vulnerability affects authenticated users who can submit crafted XML requests containing malicious DTD references, making it particularly dangerous in environments where user authentication is required for system access.
The technical implementation of this XXE vulnerability occurs within the XML parsing functionality of the SAP NetWeaver application server, specifically when processing XML content through the com.sap.km.cm.ice module. When a malicious user submits an XML request containing a crafted DTD that references external entities, the system processes these entities without proper validation, allowing the attacker to access local system resources. This flaw enables two primary attack vectors: arbitrary file reading and server-side request forgery attacks. The XML parser fails to properly sanitize external entity references, leading to potential information disclosure and unauthorized system interactions. The vulnerability is particularly concerning because it operates at the XML processing layer, where attackers can leverage the system's legitimate XML handling capabilities to bypass normal security controls.
The operational impact of CVE-2017-11457 extends beyond simple data theft, creating significant risks for SAP NetWeaver AS JAVA environments. Attackers can leverage this vulnerability to read sensitive files from the application server's file system, potentially accessing configuration files, database credentials, or other confidential information stored locally. The server-side request forgery component allows attackers to make unauthorized requests from the vulnerable server to internal network services, effectively using the SAP system as a proxy for attacks against other internal systems. This creates a potential lateral movement vector within network environments, as attackers can use the compromised system to target other internal hosts that might be protected by firewalls or other network security controls. The vulnerability's classification under ATT&CK technique T1071.004 (Application Layer Protocol: Web Protocols) highlights its impact on web application security and the potential for exploitation through standard web-based attack vectors.
Organizations affected by this vulnerability should implement immediate mitigations to protect their SAP NetWeaver AS JAVA environments. The primary defense involves configuring the XML parser to disable external entity processing and DTD resolution entirely, which prevents the exploitation of XXE vulnerabilities. SAP has released Security Note 2387249 with specific patch recommendations and configuration guidelines that organizations should implement immediately. Additional protective measures include network segmentation to limit access to vulnerable systems, implementing web application firewalls that can detect and block malicious XML content, and conducting thorough security assessments of XML processing components throughout the application stack. The vulnerability demonstrates the importance of proper input validation and secure coding practices in enterprise applications, particularly those handling XML data, and underscores the need for regular security updates and vulnerability assessments in complex enterprise systems.