CVE-2021-33677 in NetWeaver ABAP Server
Summary
by MITRE • 07/14/2021
SAP NetWeaver ABAP Server and ABAP Platform, versions - 700, 702, 730, 731, 804, 740, 750, 784, expose functions to external which can lead to information disclosure.
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Analysis
by VulDB Data Team • 07/18/2021
SAP NetWeaver ABAP Server and ABAP Platform versions 700, 702, 730, 731, 804, 740, 750, and 784 contain a vulnerability that exposes internal functions to external attackers, creating potential information disclosure risks. This vulnerability falls under the category of improper access control and information exposure, which is classified as CWE-200 in the Common Weakness Enumeration catalog. The flaw exists in the server's function interface where certain internal ABAP functions are accessible through external communication channels without proper authentication or authorization checks. This exposure allows malicious actors to access sensitive system information, potentially including database structures, system configurations, and internal processing details that should remain protected within the SAP environment.
The technical implementation of this vulnerability stems from inadequate input validation and access control mechanisms within the ABAP platform's communication layer. When external systems or users attempt to interact with the SAP NetWeaver server through standard communication protocols, the system fails to properly validate the source and intent of these requests. This allows unauthorized access to internal functions that are typically restricted to legitimate internal processes or authorized administrative users. The vulnerability specifically affects the ABAP server's ability to distinguish between legitimate internal function calls and external requests, creating a pathway for information disclosure attacks. According to the ATT&CK framework, this vulnerability maps to T1082 - System Information Discovery and T1566 - Phishing, as attackers can leverage this exposure to gather system intelligence and potentially escalate privileges.
The operational impact of this vulnerability extends beyond simple information disclosure, as the exposed functions may contain sensitive data that could be exploited for further attacks. Attackers could potentially use the disclosed information to identify system weaknesses, understand internal processing flows, or discover potential entry points for more sophisticated attacks. The exposure affects multiple versions of the SAP platform, indicating a widespread issue that requires immediate attention across various organizational systems. Organizations using these SAP versions face increased risk of targeted attacks, as the vulnerability provides attackers with valuable reconnaissance data that can be used to plan more effective exploitation strategies. The disclosure of internal system functions also creates opportunities for attackers to bypass security controls and potentially gain unauthorized access to sensitive business data.
Mitigation strategies for this vulnerability should focus on implementing proper access controls and input validation mechanisms within the SAP environment. Organizations should immediately apply the relevant SAP security notes and patches that address this specific issue, ensuring that internal functions are properly restricted from external access. Network segmentation and firewall rules should be implemented to limit access to SAP systems, particularly restricting external communication to only necessary ports and protocols. Additionally, organizations should conduct comprehensive security assessments to identify any other exposed functions or interfaces that may present similar risks. The implementation of robust authentication mechanisms and regular security monitoring can help detect and prevent unauthorized access attempts. According to industry best practices, organizations should also consider implementing application firewalls and intrusion detection systems specifically configured to monitor SAP communication patterns and identify potential exploitation attempts. Regular vulnerability scanning and security audits should be performed to ensure that no additional exposure points exist within the SAP infrastructure.