# Onapsis Security Advisory 2021-0018: [Multiple CVEs] Memory Corruption
vulnerability in SAP NetWeaver ABAP Gateway service


## Impact on Business

An unauthenticated attacker without specific knowledge of the system can
send a
specially crafted packet over a network which will trigger an internal
error in
the system causing the system to crash and rendering it unavailable.


## Advisory Information

- Public Release Date: 11/22/2021
- Security Advisory ID: ONAPSIS-2021-0018
- Researcher(s): Yvan Genuer


## Vulnerability Information

- Vendor: SAP
- Affected Components: All SAP kernel 32 and 64 bits, unicode and no-unicode
  - SAP KERNEL 7.22
  - SAP KERNEL 7.22EXT
  - SAP KERNEL 7.49
  - SAP KERNEL 7.53
  - SAP KERNEL 7.73
  - SAP KERNEL 7.77
  - SAP KERNEL 7.81
  - SAP KERNEL 8.04

  (Check SAP Note 3020209 for detailed information on affected releases)

- Vulnerability Class: CWE-20, CWE-125, CWE-476
- CVSS v3 score: 7.5 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Risk Level: High
- Assigned CVE:
  CVE-2021-27597
  CVE-2021-27633
  CVE-2021-27634
- Vendor patch Information: SAP Security NOTE 3020209


## Affected Components Description

The SAP Gateway server is the component that manages the communication
between
SAP system and the rest of the world. This is a mandatory service for SAP
Netweaver system, whitout it any background communication to the system is
not
possible, make the system useless.


## Vulnerability Details

CVE-2021-27597: An improper input validation for a memory function in
`GwCheckReceivedSapParams()` exists in SAP RFC Gateway service. The source
pointer is calculated partially with attacker controlled inputs. When this
`GW_REQ*` pointer’s is used again in `GwSearchConn()`, to get another
offset, it
leads to unattended behavior or crash.

CVE-2021-27633: A memory corruption vulnerability exists for `ThCPIC()` in
Disp+work binary through the SAP RFC Gateway service. An attacker can craft
a
malicious RFC packet to reach a particular part of function `ThrtHdlAppc()`,
where inputs, after a few modifications, are sent to disp+work with
`ThSAPCMSEND()`. Leading it to crash in `ThCPIC()`.

CVE-2021-27634: A memory corruption vulnerability exists for
`ThCpicDtCreate()`
in Disp+work binary through the SAP RFC Gateway service. In normal workload,
RFC requests received by the gwrd are forwarded to a work process type DIA
to
perform an ABAP task. These requests are stored in `pendingRequests` part in
memory. An attacker can craft a valid RFC packet and force the service to
store
malicious entry in `pendingRequests` aera. Leading the disp+work to crash.


## Solution

SAP has released SAP Note 3020209 which provide patched versions of the
affected components.

The patches can be downloaded from
https://launchpad.support.sap.com/#/notes/3020209.

Onapsis strongly recommends SAP customers to download the related
security fixes and apply them to the affected components in order to
reduce business risks.


## Report Timeline

 - MM-DD-YYYY:
 - 02/01/2021: Onapsis sends details to SAP
 - 02/04/2021: SAP provides internal ID
 - 02/08/2021: SAP confirms CVSS
 - 06/09/2021: SAP releases SAP Note fixing the issue.
 - 11/22/2021: Advisory published

## References

- Onapsis blogpost:
https://www.onapsis.com/blog/sap-security-patch-day-june-2021-multiple-memory-corruption-vulnerabilities-can-lead-system
- CVE Mitre:
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-27597
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-27633
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-27634
- Vendor Patch:
https://launchpad.support.sap.com/#/notes/3020209


## About Onapsis Research Labs

Onapsis Research Labs provides the industry analysis of key security
issues that impact business-critical systems and applications.
Delivering frequent and timely security and compliance advisories with
associated risk levels, Onapsis Research Labs combine in-depth knowledge
and experience to deliver technical and business-context with sound
security judgment to the broader information security community.

Find all reported vulnerabilities at
https://github.com/Onapsis/vulnerability_advisories


## About Onapsis, Inc.

Onapsis protects the mission-critical applications that run the global
economy,
from the core to the cloud. The Onapsis Platform uniquely delivers
actionable
insight, secure change, automated governance and continuous monitoring for
critical
systems—ERP, CRM, PLM, HCM, SCM and BI applications—from leading vendors
such as SAP,
Oracle, Salesforce and others, while keeping them protected and compliant.

For more information, connect with us on Twitter or LinkedIn, or visit us at
https://www.onapsis.com.


## License
This advisory is licensed under a [Creative Commons 4.0 BY-ND International
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