Message-ID: <8acb87ad-f333-b24b-6ea0-318da6b82c26@sec-consult.com>
Date: Tue, 17 Jan 2023 13:43:47 +0000
From: "SEC Consult Vulnerability Lab,
 Research via Fulldisclosure" <fulldisclosure@...lists.org>
To: "fulldisclosure@...lists.org" <fulldisclosure@...lists.org>
Subject: [FD] SEC Consult SA-20230117-0 :: Pre-authenticated Remote Code
 Execution in cs.exe (@OpenText Content Server component of OpenText
 Extended ECM)

SEC Consult Vulnerability Lab Security Advisory < 20230117-0 >
=======================================================================
               title: Pre-authenticated Remote Code Execution in cs.exe
             product: OpenText™ Content Server component of OpenText™ Extended ECM
  vulnerable version: 20.4 - 22.3
       fixed version: 22.4
          CVE number: CVE-2022-45923
              impact: Critical
            homepage: https://www.opentext.com/
               found: 2022-09-16
                  by: Armin Stock (Atos)
                      SEC Consult Vulnerability Lab

                      An integrated part of SEC Consult, an Atos company
                      Europe | Asia | North America

                      https://www.sec-consult.com

=======================================================================

Vendor description:
-------------------
"OpenText™ Extended ECM is an enterprise CMS platform that securely governs the
information lifecycle by integrating with leading enterprise applications, such
as SAP®, Microsoft® 365, Salesforce and SAP SuccessFactors®. Bringing content
and processes together, Extended ECM provides access to information when and
where it’s needed, improves decision-making and drives operational effectiveness."

Source: https://www.opentext.com/products/extended-ecm


Business recommendation:
------------------------
The vendor provides a patch which should be installed immediately.


Vulnerability overview/description:
-----------------------------------
1) Pre-authenticated Remote Code Execution in cs.exe (CVE-2022-45923)
The `Common Gateway Interface (CGI)` program `cs.exe` of the `Content Server`
has a vulnerability, which allows an attacker to increase/decrease an arbitrary
memory address by 1 and to trigger a call to a method of a `vftable` with a
`vftable pointer` value chosen by the attacker.

The `cs.exe` does de-serialize (crack) the user provided data in the `_fInArgs`
parameter, if the parameter `_ApiName` is set. During this de-serialization to
a `class KOSValue` object, the function `obj_ref_cracker` can be called. This
function tries to create a new `class KOSValue` object with an unknown class ID
of `3`.

As the class ID is unknown the function returns an object of type
`KOSValueBaseClass` instead of `KOSObjRefClass`, but the value of the
`class_ptr` attribute of the new `class KOSValue` object is controlled by the
attacker. This new object can then be used to increase/decrease arbitrary
memory addresses and call methods of its `vftable` via the functions
`KOSValueBaseClass::AddReference` and `KOSValueBaseClass::ReleaseReference`.


Proof of concept:
-----------------
1) Pre-authenticated Remote Code Execution in cs.exe (CVE-2022-45923)
The following request crashes the `CGI` binary `cs.exe` with an `access
violation exception - 0xC0000005` trying to read memory from address
`0xAAAA+8`:

-------------------------------------------------------------------------------
[ PoC removed, will be published at a later date ]
-------------------------------------------------------------------------------

There are `.dll` files (`libaprutil-1` & `libapriconv-1.dll`) which are not
compiled with the security flag `Address Space Layout Randomization - ASLR`
enabled, which can be used to achieve remote code execution.

-------------------------------------------------------------------------------
.\winchecksec.exe --json (get-item C:\OPENTEXT-22\cgi\*.dll) > .\checksec-results.json
-------------------------------------------------------------------------------

-------------------------------------------------------------------------------
cat checksec-results.json | jq -r '.[] | [.path, .mitigations.aslr.presence] | @csv'

"icudt69.dll","Present"
"icuin69.dll","Present"
"icuio69.dll","Present"
"icutu69.dll","Present"
"icuuc69.dll","Present"
"jsoncpp.dll","Present"
"libapr-1.dll","Present"
"libapriconv-1.dll","NotPresent"
"libaprutil-1.dll","NotPresent"
"libcrypto-1_1-x64.dll","Present"
"libexpat.dll","Present"
"libssl-1_1-x64.dll","Present"
"llcrypt.dll","Present"
"llisapi.dll","Present"
"llkernel.dll","Present"
"llresources.dll","Present"
"log4cxx.dll","Present"
"PocoFoundation.dll","Present"
-------------------------------------------------------------------------------


Vulnerable / tested versions:
-----------------------------
The following version has been tested:
* 22.1 (16.2.19.1803)

The following versions are vulnerable according to the vendor:
* 20.4 - 22.3


Vendor contact timeline:
------------------------
2022-10-07: Vendor contacted via security@...ntext.com
2022-10-07: Vendor acknowledged the email and is reviewing the reports
2022-11-18: Vendor confirms all vulnerabilities and is working on a patch aimed to
             be released in November
2022-11-24: Vendor delays the patch "few days/weeks into December"
2022-11-25: Requesting CVE numbers (Mitre)
2022-12-15: Vendor delays the patch and provides a release date: January 16th 2023
2023-01-17: Public release of security advisory


Solution:
---------
Upgrade to at least version 22.4 or apply hotfixes which can be downloaded at
the vendor's page:
https://support.opentext.com/csm?id=kb_article_view&sysparm_article=KB0781429


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
The SEC Consult Vulnerability Lab is an integrated part of SEC Consult, an
Atos company. It ensures the continued knowledge gain of SEC Consult in the
field of network and application security to stay ahead of the attacker. The
SEC Consult Vulnerability Lab supports high-quality penetration testing and
the evaluation of new offensive and defensive technologies for our customers.
Hence our customers obtain the most current information about vulnerabilities
and valid recommendation about the risk profile of new technologies.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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EOF Armin Stock / @2023
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