(The following pre-advisory is also available in PDF format for download at:
Pre-Advisory Name: SAP RFC_SET_REG_SERVER_PROPERTY RFC Function Denial Of Service
Vulnerability Class: Denial Of Service
Release Date: 2007-04-03
. SAP RFC Library 6.40
. SAP RFC Library 7.00
. 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 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
Author: Mariano Nuñez Di Croce
Vendor Status: Confirmed. Updates Released.
Reference to Vulnerability Disclosure Policy: http://www.cybsec.com/vulnerability_policy.pdf
"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_SET_REG_SERVER_PROPERTY RFC function is used to set properties of externally registered RFC servers. This function is installed by default in
every external RFC server.
This function allows defining the exclusive use of an external registered RFC server, denying access to other clients.
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.
This vulnerability may allow an attacker to remotely prevent licit clients to connect with external RFC servers.
SAP has released patches to address this vulnerability. Affected customers should apply the patches immediately.
More information can be found on SAP Note 1005397.
. 2006-11-21: Initial Vendor Contact.
. 2006-12-01: Vendor Confirmed Vulnerability.
. 2007-01-09: Vendor Releases Update for version 6.40.
. 2007-01-09: Vendor Releases Update for version 7.00.
. 2007-04-03: Pre-Advisory Public Disclosure.
Thanks goes to Victor Montero and Gustavo Kunst.
For more information regarding the vulnerability feel free to contact the author at mnunez <at> cybsec <dot> com.
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