CVE-2019-0365 in SAP
Summary
by MITRE
SAP Kernel (RFC), KRNL32NUC, KRNL32UC and KRNL64NUC before versions 7.21, 7.21EXT, 7.22, 7.22EXT, KRNL64UC, before versions 7.21, 7.21EXT, 7.22, 7.22EXT, 7.49, 7.73 and KERNEL before versions 7.21, 7.49, 7.53, 7.73, 7.76 SAP GUI for Windows (BC-FES-GUI) before versions 7.5, 7.6, and SAP GUI for Java (BC-FES-JAV) before version 7.5, allow an attacker to prevent legitimate users from accessing a service, either by crashing or flooding the service.
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Analysis
by VulDB Data Team • 08/18/2020
The vulnerability identified as CVE-2019-0365 affects multiple SAP kernel components and client applications including RFC implementations KRNL32NUC, KRNL32UC, KRNL64NUC, KRNL64UC, and various SAP GUI versions for Windows and Java platforms. This weakness manifests as a denial of service condition that can be exploited by malicious actors to disrupt legitimate user access to SAP services. The affected kernel versions span across multiple release lines including 7.21, 7.22, 7.49, 7.53, 7.73, and 7.76, indicating a widespread impact across SAP's product ecosystem. The vulnerability specifically targets the service availability aspect of SAP systems, allowing attackers to either crash services or flood them with excessive requests that prevent legitimate users from accessing critical business applications.
The technical flaw resides in the insufficient input validation and resource management within the SAP kernel's remote function call processing mechanisms. When processing certain malformed or crafted requests, the affected components fail to properly handle error conditions or resource allocation, leading to service disruption. This vulnerability operates at the network communication level where RFC (Remote Function Call) protocols are processed, making it particularly dangerous as it can be exploited from remote locations without requiring elevated privileges. The flaw essentially creates a condition where the kernel components become unresponsive or crash entirely, thereby blocking legitimate user sessions and business processes that depend on these services. From a cybersecurity perspective, this vulnerability aligns with CWE-400, which addresses "Uncontrolled Resource Consumption" and represents a classic denial of service attack vector.
The operational impact of CVE-2019-0365 extends beyond simple service interruption to potentially cause significant business disruption in enterprise environments that rely heavily on SAP systems. Organizations may experience extended downtime during exploitation periods, leading to productivity losses and potential revenue impacts. The vulnerability affects critical business processes that depend on RFC communications between different SAP modules and external systems, making it particularly dangerous in mission-critical environments. Attackers can leverage this weakness to perform sustained denial of service attacks that may require manual intervention to restore service availability. The impact is compounded by the fact that multiple SAP GUI versions are affected, suggesting that organizations may have to update or patch numerous client applications simultaneously to achieve complete protection. This vulnerability also aligns with ATT&CK technique T1499.004, which covers "Endpoint Denial of Service" and represents a common attack pattern used in enterprise network disruption campaigns.
Organizations should immediately implement patches and updates provided by SAP to address this vulnerability across all affected kernel versions and GUI client applications. The remediation process requires careful coordination between IT operations and security teams to ensure complete coverage of all affected systems without causing operational disruption. Network segmentation and monitoring should be implemented to detect unusual traffic patterns that may indicate exploitation attempts. Additionally, organizations should review their access controls and implement rate limiting mechanisms to reduce the effectiveness of potential denial of service attacks. Regular vulnerability assessments and penetration testing should be conducted to identify similar weaknesses in the SAP ecosystem. The vulnerability serves as a reminder of the importance of maintaining up-to-date security patches in enterprise environments and demonstrates how seemingly minor implementation flaws can lead to significant operational impacts in critical business systems.