# Onapsis Security Advisory 2021-0019: [Multiple CVEs] Memory Corruption
vulnerability in SAP NetWeaver ABAP IGS 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-2021-0019
- Researcher(s): Yvan Genuer


## Vulnerability Information

- Vendor: SAP
- Affected Components:
  - SAP IGS 7.20
  - SAP IGS 7.20EXT
  - SAP IGS 7.53
  - SAP IGS 7.20\_EX2
  - SAP IGS 7.81

  (Check SAP Note 3021050 for detailed information on affected releases)

- Vulnerability Class: CWE-20, CWE-125, CWE-834
- CVSS v3 score: 5.9 AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- Risk Level: High
- Assigned CVE:
  CVE-2021-27620
  CVE-2021-27622
  CVE-2021-27624
  CVE-2021-27625
  CVE-2021-27626
  CVE-2021-27627
- Vendor patch Information: SAP Security NOTE 3021050


## Affected Components Description

The SAP IGS is a widely-used, server-based engine for generating graphical
and
non-graphical content based on data from an SAP system or an external
system.
An integral part of its architecture are different interpreters responsible
for
the semantic processing of the received data. The appropriate interpreter is
selected by a portwatcher and depends on the basis of the requested type of
information (ex: chart, map, zip).


## Vulnerability Details

CVE-2021-27620: An out of bounds read access exists in function
`Ups::AddPart()`
in IGS portwatcher binary through the SAP IGS service. The function uses
directly a part of the packet as a counter in movs instruction.

CVE-2021-27622: It is possible to trigger an undesired excessive iteration
vulnerability in `CDrawRaster::LoadImageFromMemory` in IGS portwatcher
library
imgconv.so through the SAP IGS service. In particular image requests, the
number
of color planes can be overwritten by the number of bits per pixel. This
led to
an excessive loop where a movzx instruction eventually crashed.

CVE-2021-27624: An undesired excessive iteration vulnerability exists in
function `CiXMLIStreamRawBuffer::readRaw` in IGS Portwatcher binary through
the
SAP IGS service. In particular IGS packet type, the size of the provided
input
is directly read from the packet itself. An attacker can craft a malicious
packet to force the function to read outside his memory slot. After a few
iterations, around 0x5780, the program crashed.

CVE-2021-27625: A memory corruption vulnerability exists in function
`CXmlUtility::CheckLength` in IGS library xmlchart.so through the SAP IGS
service. The function `CChartCuParser::Load` dereference a pointer due to
the
high value provided into the igs table entry for the provided input. This
leads
to set high offset value for next input, leading to crash.

CVE-2021-27626: A memory corruption vulnerability exists in function
`CMiniXMLParser::Parse` in IGS Portwatcher binary through the SAP IGS
service.
By crafting a malicious igs packet, the attacker can provide the wrong size
for
the provided input content. This size is directly read from the IGS table
entry
CLWD, then used as counter to read the content part

CVE-2021-27627: A memory corruption vulnerability exists in function
`ChartInterpreter::DoIt()` in IGS Portwatcher binary through the SAP IGS
service. This function fails to verify the return value of several
`strchr()`
when checking the content of parameter input for a particular interpreter.
By
crafting a malicious network packet, an attacker can force the function to
return 0x0 at a particular point, leading to breaking the calculation of the
next parameter offset and crash.


## Solution

SAP has released SAP Note 3021050 which provide patched versions of the
affected components.

The patches can be downloaded from
https://launchpad.support.sap.com/#/notes/3021050.

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

 - 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-2021-27620
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-27622
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-27624
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-27625
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-27626
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-27627
- Vendor Patch:
https://launchpad.support.sap.com/#/notes/3021050


## 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.

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