CVE-2025-27429: SAP S/4HANA RCE Vulnerability

CVE-2025-27429 Overview

CVE-2025-27429 is a critical code injection vulnerability affecting SAP S/4HANA that allows authenticated attackers to inject arbitrary ABAP code through a vulnerable function module exposed via Remote Function Call (RFC). This flaw bypasses essential authorization checks within the SAP system, effectively creating a backdoor that enables full system compromise. The vulnerability undermines the confidentiality, integrity, and availability of affected SAP environments.

Critical Impact

This vulnerability enables authenticated users to inject and execute arbitrary ABAP code, bypassing authorization controls and potentially achieving complete system compromise of SAP S/4HANA environments.

Affected Products

• SAP S/4HANA (versions as specified in SAP Security Note #3581961)

Discovery Timeline

• April 8, 2025 - CVE-2025-27429 published to NVD
• April 8, 2025 - Last updated in NVD database

Technical Details for CVE-2025-27429

Vulnerability Analysis

This vulnerability (CWE-94: Improper Control of Generation of Code, also known as Code Injection) resides within a function module exposed via SAP's RFC interface. RFC is a standard SAP communication protocol that enables programs to call functions in remote systems. The vulnerability allows authenticated users with standard privileges to inject arbitrary ABAP (Advanced Business Application Programming) code into the system.

The most concerning aspect of this flaw is its ability to bypass essential authorization checks that would normally prevent unauthorized code execution. Once exploited, an attacker gains the ability to execute arbitrary code with elevated privileges, potentially leading to complete system takeover. This includes the ability to read, modify, or delete sensitive business data, create unauthorized administrative accounts, and disrupt critical business processes.

Root Cause

The root cause of this vulnerability lies in insufficient input validation and improper authorization controls within the RFC-exposed function module. The affected component fails to adequately sanitize user-supplied input before processing it as executable ABAP code. Additionally, the authorization mechanisms that should prevent unprivileged users from executing arbitrary code are improperly implemented or missing entirely, allowing the bypass of security controls.

Attack Vector

The attack vector for CVE-2025-27429 is network-based, requiring the attacker to have valid user credentials with basic privileges on the target SAP S/4HANA system. An attacker can exploit this vulnerability by sending specially crafted RFC requests to the vulnerable function module.

The exploitation process involves crafting malicious ABAP code payloads and delivering them through the RFC interface to the vulnerable function module. The injected code executes with elevated privileges, bypassing normal authorization checks. This attack requires low complexity and no user interaction, making it particularly dangerous in enterprise environments where SAP S/4HANA systems often contain critical business data.

Detection Methods for CVE-2025-27429

Indicators of Compromise

• Unusual RFC calls to the affected function module from unexpected user accounts or source systems
• Unexpected ABAP code execution or new program registrations in the SAP system
• Anomalous user activity patterns, particularly privilege escalation or access to sensitive data
• Suspicious entries in SAP Security Audit Log (SM21) indicating unauthorized function module access

Detection Strategies

• Enable and monitor SAP Security Audit Log for RFC function module access patterns
• Implement SIEM integration to correlate SAP security events with network activity
• Deploy SAP-specific intrusion detection rules to identify malicious RFC payload patterns
• Review transaction code usage patterns, particularly for development transactions (SE38, SE80)

Monitoring Recommendations

• Configure real-time alerting for RFC calls to the affected function module
• Monitor for creation of new ABAP programs or modifications to existing code
• Track user authorization changes and privilege escalations within SAP
• Implement baseline monitoring for normal RFC communication patterns to detect anomalies

How to Mitigate CVE-2025-27429

Immediate Actions Required

• Apply the security patch from SAP Security Note #3581961 immediately
• Review RFC destinations and restrict access to the affected function module
• Audit user accounts with RFC access privileges and apply least-privilege principles
• Enable enhanced SAP Security Audit Logging for RFC activities

Patch Information

SAP has released a security patch addressing this vulnerability as part of their April 2025 Security Patch Day. Organizations should obtain and apply the patch from SAP Security Note #3581961. The patch introduces proper input validation and authorization checks for the affected RFC function module. Refer to the SAP Security Patch Day Announcement for complete patch details and installation instructions.

Workarounds

• Restrict RFC access to the vulnerable function module using authorization objects S_RFC and S_RFCACL
• Implement network segmentation to limit RFC connectivity to trusted systems only
• Disable the affected function module if not required for business operations
• Deploy additional authentication requirements for RFC connections using SNC (Secure Network Communications)