(The following pre-advisory is also available in PDF format for download at:
http://www.cybsec.com/vuln/CYBSEC-Security_Advisory_SAP_RFC_START_GUI_RFC_Function_Buffer_Overflow.pdf )


CYBSEC S.A.
www.cybsec.com

Pre-Advisory Name: SAP RFC_START_GUI RFC Function Buffer Overflow
==================

Vulnerability Class: Buffer Overflow
====================

Release Date: 2007-04-03
=============

Affected Applications:
======================
. SAP RFC Library 6.40
. SAP RFC Library 7.00

Affected Platforms:
===================

. AIX 32bit
. AIX 64bit
. HP-UX on IA64 64bit
. HP-UX on PA-RISC 64bit
. Linux on IA32 32bit
. Linux on IA64 64bit
. Linux on Power 64bit
. Linux on x86_64 64bit
. Linux on zSeries 64bit
. Mac OS
. OS/400
. OS/400 V5R2M0
. Reliant 32bit
. Solaris on SPARC 32bit
. Solaris on SPARC 64bit
. Solaris on x64_64 64bit
. TRU64 64bit
. Windows Server on IA32 32bit
. Windows Server on IA64 64bit
. Windows Server on x64 64bit
. z/OS 32bit

Local / Remote: Remote
===============

Severity: High
=========

Author: Mariano Nuñez Di Croce
=======

Vendor Status: Confirmed. Updates Released.
==============

Reference to Vulnerability Disclosure Policy: http://www.cybsec.com/vulnerability_policy.pdf
=============================================

Product Overview:
=================

"The RFC Library offers an interface to a SAP System. The RFC Library is the most commonly used and installed component of existing SAP Software. This
interface provides the opportunity to call any RFC Function in a SAP System from an external application. Moreover, the RFC Library offers the
possibility to write a RFC Server Program, which is accessible from any SAP System or external application. Most SAP Connectors use the RFC Library as
communication platform to SAP Systems."

RFC_START_GUI RFC Function is used to start SAPGUI on front-end systems. This function is installed by default in every external RFC server.

Vulnerability Description:
==========================

A remote buffer overflow vulnerability has been detected in the RFC_START_GUI RFC Function.

Technical Details:
==================

Technical details will be released three months after publication of this pre-advisory. This was agreed upon with SAP to allow their customers to
upgrade affected software prior to technical knowledge been publicly available.

Impact:
=======

This vulnerability may allow an attacker to remotely execute arbitrary commands over external RFC servers.

Solutions:
==========

SAP has released patches to address this vulnerability. Affected customers should apply the patches immediately.
More information can be found on SAP Note 1003908.

Vendor Response:
================

. 2006-11-21: Initial Vendor Contact.
. 2006-12-01: Vendor Confirmed Vulnerability.
. 2006-12-11: Vendor Releases Update for version 6.40.
. 2006-12-11: Vendor Releases Update for version 7.00.
. 2007-04-03: Pre-Advisory Public Disclosure.


Special Thanks:
===============

Thanks goes to Victor Montero and Gustavo Kunst.

Contact Information:
====================
For more information regarding the vulnerability feel free to contact the author at mnunez <at> cybsec <dot> com.



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