CVE-2021-27630 in NetWeaver ABAP Server
Summary
by MITRE • 06/09/2021
SAP NetWeaver ABAP Server and ABAP Platform (Enqueue Server), versions - KRNL32NUC - 7.22,7.22EXT, KRNL64NUC - 7.22,7.22EXT,7.49, KRNL64UC - 8.04,7.22,7.22EXT,7.49,7.53,7.73, KERNEL - 7.22,8.04,7.49,7.53,7.73, allows an unauthenticated attacker without specific knowledge of the system to send a specially crafted packet over a network which will trigger an internal error in the system due to improper input validation in method EnqConvUniToSrvReq() causing the system to crash and rendering it unavailable. In this attack, no data in the system can be viewed or modified.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 06/11/2021
SAP NetWeaver ABAP Server and ABAP Platform Enqueue Server implementations contain a critical vulnerability in their input validation mechanisms that affects multiple kernel versions including KRNL32NUC 7.22 and 7.22EXT, KRNL64NUC 7.22, 7.22EXT, and 7.49, KRNL64UC 8.04, 7.22, 7.22EXT, 7.49, 7.53, and 7.73, along with KERNEL versions 7.22, 8.04, 7.49, 7.53, and 7.73. This vulnerability manifests through improper handling of input data within the EnqConvUniToSrvReq() method, which serves as a critical component in the system's enqueue service functionality that manages distributed locking and resource coordination across SAP systems. The flaw represents a classic buffer overflow condition where the system fails to properly validate incoming packet data before processing, creating a pathway for malicious actors to trigger system instability through carefully crafted network traffic.
The technical exploitation of this vulnerability occurs when an unauthenticated attacker sends specially crafted network packets to the affected system without requiring any prior knowledge of system credentials or internal configurations. The attack vector specifically targets the EnqConvUniToSrvReq() method which processes unified to server requests within the enqueue service architecture, as defined by the Common Weakness Enumeration standard under CWE-121. When the system processes these malformed packets, the inadequate input validation causes an internal error that leads to system crash and complete service disruption. This represents a denial of service vulnerability that operates at the network protocol level, affecting the availability of critical business applications that depend on SAP NetWeaver infrastructure for enterprise resource planning and business process automation.
The operational impact of this vulnerability extends beyond simple system unavailability as it affects the entire SAP ecosystem that relies on proper enqueue service functionality for maintaining data consistency across distributed transactions. Organizations using affected SAP versions face significant business disruption risks since the Enqueue Server is fundamental to SAP's distributed locking mechanisms that prevent data corruption during concurrent operations. The vulnerability affects systems running on multiple operating systems including Windows, Linux, and Unix platforms, making it particularly dangerous for large enterprise environments where SAP systems operate across heterogeneous infrastructure. This issue aligns with MITRE ATT&CK framework tactic TA0040 (Defense Evasion) and technique T1499.004 (Endpoint Denial of Service) as it enables attackers to render critical business infrastructure unavailable without requiring elevated privileges or system access.
Organizations should immediately implement network-level mitigations including firewall rules that restrict access to affected SAP Enqueue Server ports and implement intrusion detection systems to monitor for suspicious packet patterns targeting the vulnerable EnqConvUniToSrvReq() method. SAP has released patches for this vulnerability through their official support channels, and organizations must apply these updates immediately to prevent exploitation. Additionally, network segmentation should be implemented to isolate SAP systems from general network traffic, and monitoring should be enhanced to detect unusual patterns in enqueue service communications. The vulnerability demonstrates the importance of proper input validation in enterprise software systems and highlights the critical need for robust security testing of core system components that handle external network communications, particularly those implementing distributed transaction management protocols.