CVE-2016-3974 in Netweaver Java AS
Summary
by MITRE
XML external entity (XXE) vulnerability in the Configuration Wizard in SAP NetWeaver Java AS 7.4 allows remote attackers to cause a denial of service, conduct SMB Relay attacks, or access arbitrary files via a crafted XML request, related to the ctcprotocol servlet, aka SAP Security Note 2235994.
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Analysis
by VulDB Data Team • 08/23/2024
The CVE-2016-3974 vulnerability represents a critical XML external entity processing flaw within SAP NetWeaver Java Application Server version 7.4 configuration wizard component. This vulnerability specifically targets the ctcprotocol servlet which handles XML processing for configuration operations, creating a pathway for remote attackers to exploit the system through malformed XML requests. The flaw stems from insufficient input validation and improper handling of external entity references in the XML parser, allowing malicious actors to manipulate the processing behavior of the affected component.
The technical implementation of this vulnerability enables attackers to leverage XML external entity processing to perform multiple malicious activities simultaneously. When the vulnerable servlet processes crafted XML requests containing external entity declarations, the XML parser resolves these references without proper sanitization, leading to potential file system access, denial of service conditions, and SMB relay attack capabilities. The vulnerability specifically affects the configuration wizard functionality which typically handles administrative operations and system configuration tasks, making it particularly dangerous for privileged access scenarios.
From an operational impact perspective, this vulnerability creates significant security risks for SAP NetWeaver environments, as it allows remote attackers to escalate privileges and access sensitive system resources without authentication. The denial of service component can disrupt critical business operations by rendering the configuration wizard unavailable, while the SMB relay capabilities enable attackers to leverage existing network credentials for unauthorized access to other systems. The arbitrary file access component poses additional risks for data confidentiality and integrity, potentially exposing sensitive configuration files, user credentials, or system information. This vulnerability directly maps to CWE-611 (Improper Restriction of XML External Entity Reference) and aligns with ATT&CK technique T1213.002 (Data from Information Repositories) and T1499.004 (Endpoint Denial of Service).
Organizations affected by this vulnerability should implement immediate mitigations including disabling external entity processing in XML parsers, implementing proper input validation for all XML processing components, and restricting network access to the affected servlet endpoints. SAP released Security Note 2235994 with specific patches and workarounds addressing this vulnerability, recommending the application of the latest hotpatches or the implementation of network segmentation to limit access to the vulnerable configuration wizard functionality. The mitigation strategy should also include monitoring for suspicious XML processing activities and implementing proper access controls to prevent unauthorized access to administrative components. Additionally, organizations should conduct comprehensive vulnerability assessments to identify other potentially affected components within their SAP environments that may share similar XML processing vulnerabilities, as this type of flaw often indicates broader architectural weaknesses in XML handling implementations.