# Onapsis Security Advisory 2022-0001: HTTP Request Smuggling in SAP Web  
## Impact on Business  
By injecting an HTTP request as a prefix into a victim's request, a  
malicious user  
is able to cause damage in different ways, such as producing a Denial of  
Service by  
setting an invalid request as a prefix.  
It is also possible to inject a valid prefixed request that will include the  
victim's information from its original request. This can be leveraged to  
malicious requests with the victim's credentials or information, or even  
user data.  
HTTP smuggling can also be combined with other vulnerabilities such as a  
XSS or  
reflected content (not vulnerability by itself), by injecting a request to  
vulnerable application/web page as a prefix. If the attacker is able to set  
prefix of the victim request and also knows a reflected XSS (it can also  
work with  
other content reflection), then the response will include a malicious  
script that  
will be executed on the victim's browser.  
This vulnerability is also useful to perform Web Cache Poisoning.  
The HTTP caches in the different layers will see valid requests for which  
the response  
should be stored (considered static), but the actual request is modified by  
the prefix  
of the attacker to retrieve another resource, which should not be stored in  
the cache.  
As an example, if a user requests an image, the server will probably cache  
the response as  
the resource is static. However, if this request is prefixed by another  
request which  
returns sensible data, such as personal information, then this response  
will be stored  
in the cache. Therefore, when the attacker requests the same image, all the  
personal information will be retrieved.  
Finally, a critical information disclosure could end up in session  
hijacking and further  
attacks. This can be performed by combining HTTP Desynchronization with  
Open Redirect, and  
use the victim's request as the parameter of the redirect location. This  
would force the  
victim to send its original request to the attacker, including critical  
data such as session  
cookies or query parameters.  
## Advisory Information  
- Public Release Date: 04/05/2022  
- Security Advisory ID: ONAPSIS-2022-0001  
- Researcher(s): Martin Doyhenard, Yvan Genuer  
## Vulnerability Information  
- Vendor: SAP  
- Affected Components:  
- KRNL64NUC 7.22, 7.22EXT, 7.49  
- KRNL64UC 7.22, 7.22EXT, 7.49, 7.53  
- WEBDISP 7.53, 7.77, 7.81  
- KERNEL 7.22, 7.49, 7.53, 7.77, 7.81, 7.83  
(Check SAP Note 3080567 for detailed information on affected releases)  
- Vulnerability Class: CWE-444  
- CVSS v3 score: 8.9 AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:L  
- Risk Level: High  
- Assigned CVE: CVE-2021-38162  
- Vendor patch Information: SAP Security NOTE 3080567  
## Affected Components Description  
The SAP Web dispatcher works as a frontend server between the Internet and  
one or more  
backend systems. Which consists of one or more SAP Netweaver ABAP, SAP  
JAVA, SAP HANA, as well as third party application servers.  
## Vulnerability Details  
An HTTP desynchronization vulnerability, TE.CL type is present in SAP Web  
Dispatcher if the parameter ```wdisp/HTTP/use_pool_for_new_conn``` is  
Pool connection related SAP Note :  
* 2007212 - Tuning SAP Web Dispatcher and ICM for high load  
* 953784 - SAP Web Dispatcher Connection Pooling  
If an attacker sends both HTTP headers "Content-Length" (CL) and  
"Transfer-Encoding" (TE) in the same HTTP request, the SAP Webdispatcher  
processes the TE header and treats the message body as using chunked  
This request is forwarded on to the SAP system ICM service, which processes  
the CL header and determines the body size with it. The rest of the request  
left unprocessed and the ICM will treat it as being the start of the next  
in the sequence.  
This can be leveraged to gain control of requests issued by other users, and  
even obtain sensitive information by retrieving the victim's requests and  
## Solution  
SAP has released SAP Note 3080567 which provides patched versions of the  
affected components.  
The patches can be downloaded from  
Onapsis strongly recommends SAP customers to download the related  
security fixes and apply them to the affected components in order to  
reduce business risks.  
## Report Timeline  
- 07/12/2021: Onapsis sends details to SAP  
- 07/12/2021: SAP provides internal ID  
- 08/09/2021: Vulnerability in progress  
- 09/14/2021: SAP releases SAP Note fixing the issue.  
- 05/04/2022: Advisory Published  
## References  
- Onapsis blogpost:  
- CVE Mitre:  
- Vendor Patch:  
## About Onapsis Research Labs  
Onapsis Research Labs provides the industry analysis of key security  
issues that impact business-critical systems and applications.  
Delivering frequent and timely security and compliance advisories with  
associated risk levels, Onapsis Research Labs combine in-depth knowledge  
and experience to deliver technical and business-context with sound  
security judgment to the broader information security community.  
Find all reported vulnerabilities at  
## About Onapsis, Inc.  
Onapsis protects the mission-critical applications that run the global  
from the core to the cloud. The Onapsis Platform uniquely delivers  
insight, secure change, automated governance and continuous monitoring for  
systems—ERP, CRM, PLM, HCM, SCM and BI applications—from leading vendors  
such as SAP,  
Oracle, Salesforce and others, while keeping them protected and compliant.  
For more information, connect with us on Twitter or LinkedIn, or visit us at  
This email and any files transmitted with it are confidential and intended   
solely for the use of the individual or entity to whom they are addressed.   
If you have received this email in error please notify the system manager.   
This message contains confidential information and is intended only for the   
individual named. If you are not the named addressee you should not   
disseminate, distribute or copy this e-mail.  
Please notify the sender   
immediately by e-mail if you have received this e-mail by mistake and   
delete this e-mail from your system. If you are not the intended recipient   
you are notified that disclosing, copying, distributing or taking any   
action in reliance on the contents of this information is strictly