CVE-2021-33664 in NetWeaver Application Server ABAP
Summary
by MITRE • 06/09/2021
SAP NetWeaver Application Server ABAP (Applications based on Web Dynpro ABAP), versions - SAP_UI - 750,752,753,754,755, SAP_BASIS - 702, 731 does not sufficiently encode user-controlled inputs, resulting in Cross-Site Scripting (XSS) vulnerability.
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Analysis
by VulDB Data Team • 06/12/2021
SAP NetWeaver Application Server ABAP represents a critical enterprise application platform that serves as the foundation for numerous business-critical applications across global organizations. This platform encompasses various components including Web Dynpro ABAP applications and the underlying SAP_BASIS framework, which together form the backbone of enterprise resource planning and business application delivery. The vulnerability identified as CVE-2021-33664 specifically targets the input validation mechanisms within these applications, creating a significant security exposure that can be exploited by malicious actors to compromise user sessions and execute unauthorized actions. The affected versions span across multiple release branches including SAP_UI versions 750 through 755 and SAP_BASIS versions 702 and 731, indicating a widespread impact across different generations of the platform.
The technical flaw manifests as insufficient encoding of user-controlled inputs within the Web Dynpro ABAP applications, which directly violates fundamental security principles for input validation and output encoding. This vulnerability classifies under CWE-79 as Cross-Site Scripting, where malicious scripts can be injected into web applications and subsequently executed in the context of other users' browsers. The root cause lies in the application's failure to properly sanitize and encode user-supplied data before rendering it in web responses, allowing attackers to inject malicious JavaScript code through various input vectors including form fields, URL parameters, and API endpoints. The vulnerability specifically affects the Web Dynpro ABAP components that handle user interactions and data display, making it particularly dangerous as it can target the most interactive elements of enterprise applications.
The operational impact of this vulnerability extends far beyond simple data theft or display manipulation, as it provides attackers with a powerful foothold for further exploitation within enterprise networks. Successful exploitation can lead to session hijacking, where attackers can impersonate legitimate users and gain unauthorized access to sensitive business data, financial systems, and confidential enterprise information. The vulnerability enables attackers to execute malicious scripts that can capture keystrokes, steal cookies, redirect users to malicious sites, or perform actions on behalf of authenticated users. This creates significant risk for enterprise environments where SAP NetWeaver serves as the primary platform for mission-critical business applications, potentially leading to data breaches, financial losses, and compliance violations that could result in substantial regulatory penalties and reputational damage.
Organizations affected by this vulnerability should implement immediate mitigations including applying the relevant SAP security notes and patches that address the input encoding deficiencies in the affected components. The recommended approach involves configuring proper output encoding mechanisms within the Web Dynpro ABAP applications to ensure all user-supplied data is appropriately sanitized before being rendered in web responses. Security teams should also implement web application firewalls and content security policies to provide additional layers of protection against XSS attacks. According to ATT&CK framework, this vulnerability maps to T1059.007 for script injection techniques and T1566 for social engineering attacks that leverage XSS for initial access. Organizations must conduct comprehensive security assessments of their SAP environments to identify all potential injection points and ensure proper input validation is implemented across all user-facing interfaces. The remediation process should include thorough testing of patched components to verify that the encoding mechanisms function correctly and do not introduce regressions in application functionality while maintaining compliance with industry standards such as OWASP Top Ten and NIST cybersecurity frameworks.