Type packetstorm
Reporter A. Grossmann
Modified 2006-05-22T00:00:00


                                            `Release Date: 03/01/2006  
Affected Applications: SAP WebAS Kernel up to version 7.00  
Affected Platforms: Platform-Independant  
Local / Remote: Remote  
Severity: Medium to High  
Author: A. Grossmann arnold.grossmann (at)  
Vendor Status: Confirmed  
Product Overview ( cited from SAP ):  
SAP Web Application Server  
The only Application Platform for the SAP NetWeaver Suite  
SAP Web Application Server (SAP Web AS) is the application platform of SAP  
NetWeaver, i.e. it provides the complete infrastructure to develop, deploy  
and run all SAP NetWeaver applications. The major key capability of SAP Web  
AS is the full support for both the proven ABAP technology and the innovative  
open source internet-driven technologies Java, Java 2 Enterprise Edition  
(J2EE) and Web Services.  
Vulnerability Description:  
SAP Web Application Server was found to be vulnerable to an URL manipulation  
allowing an attacker to prefix the http response ( to a request containing a  
manipulated URL ) with a sequence of bytes of his choice.  
The vulnerability may be exploited to mount various attacks to gain knowledge  
of authentication information valid within the context of the WAS website  
( like cookies, usernames or passwords ). Also the vulnerability may aid an  
attacker in manipulating the way a website is cached, served or interpreted -  
leading to a false sense of trust or a partial defacement.  
Technical Details:  
One way the vulnerability can be exploited is by inserting ";%20" into the http  
request URL, followed by the characters to be inserted, replacing all  
characters with special meaning like "/", CR, LF and "=" by one of their  
illegal UTF-8- and URL-encoded representations. This results in an incorrectly  
handled http error. WAS translates each illegal character representation into  
one byte and returns the sequence chosen by the attacker, followed by some  
garbage characters built from the URL, a slightly incorrect http response-header  
plus the original http message-body, thus allowing the complete control over the  
first sequence of bytes of the response. If the attacker inserts a http message  
containing a HTML page in it's entity-body, the user's browser will render that  
page and discard the rest of the response.  
Cache manipulations might be done by letting WAS return one or multiple  
specially crafted HTTP responses within the bytes inserted. This could  
facilitate phishing or defacement style attacks.  
Exploit (Poc):  
Following proof of concept will return a html page that  
is defined by the request URL.  
Patches are provided from SAP. See SAP Note 908147 and 915084 for details.  
Vendor Response:  
* 11/29/2005: Initial Vendor Contact.  
* 11/30/2005: Technical details for the vulnerabilities sent to vendor.  
* 01/10/2006: patch provided by vendor.  
* 03/01/2006: Coordinate release of pre-advisory without technical details  
* 05/16/2006: Coordinate release of advisory with technical details