Date: Wed, 31 May 2017 13:30:34 +0200
From: "Stefan Kanthak" <stefan.kanthak@...go.de>
To: <fulldisclosure@...lists.org>
Cc: <bugtraq@...urityfocus.com>
Subject: [CVE-2017-5688] Executable installers are vulnerable^WEVIL (case 52): Intel installation framework allows arbitrary code execution with escalation of privilege

Hi @ll,

executable installers built with Intels Installation Framework,
for example "Intel SSD Toolbox - v3.4.3.exe", available from
<https://downloadcenter.intel.com/download/26574>, expose two
vulnerabilities, both resulting in arbitrary code execution
with escalation of privilege.

Vulnerability #1:
~~~~~~~~~~~~~~~~~

On a fully patched Windows 7 SP1 they load and execute (at least)
Cabinet.dll, Version.dll, RichEd20.dll, UXTheme.dll or DMWAPI.dll
(on other versions of Windows different DLLs may be affected)
from the directory they are stored (their so-called "application
directory") instead Windows' "system directory"
%SystemRoot%\System32\", resulting in arbitrary code execution.

DLL hijacking is a 20 year old, well-known and well-documented
vulnerability, and a typical (but ubiquituous) beginner's error:
see <https://cwe.mitre.org/data/definitions/426.html>,
<https://cwe.mitre.org/data/definitions/427.html>,
<https://capec.mitre.org/data/definitions/471.html>,
<https://technet.microsoft.com/en-us/library/2269637.aspx>,
<https://msdn.microsoft.com/en-us/library/ff919712.aspx> and
<https://msdn.microsoft.com/en-us/library/ms682586.aspx> plus
<https://skanthak.homepage.t-online.de/!execute.html> for more
documentation!

For software downloaded with a web browser the "application
directory" is typically the user's "Downloads" directory: see
<http://seclists.org/fulldisclosure/2015/Nov/101> and
<http://seclists.org/fulldisclosure/2015/Dec/86> plus
<https://insights.sei.cmu.edu/cert/2008/09/carpet-bombing-and-directory-poisoning.html>,
<http://blog.acrossecurity.com/2012/02/downloads-folder-binary-planting.html>,
<http://seclists.org/fulldisclosure/2012/Aug/134> and
<http://blogs.technet.com/b/srd/archive/2014/05/13/load-library-safely.aspx>

Due to the specification "requireAdministrator" in the application
manifest embedded within the executable, installers like
"Intel SSD Toolbox - v3.4.3.exe" run with administrative privileges
("protected" administrators are prompted for consent, unprivileged
standard users are prompted for an administrator password),
resulting in an escalation of privilege!

If (one of) the DLLs named above get(s) planted in the users
"Downloads" directory, for example per "drive-by download", this
vulnerability becomes a remote code execution WITH escalation of
privilege.


Proof of concept/demonstration:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

1. visit <https://skanthak.homepage.t-online.de/sentinel.html>,
   download
   <https://skanthak.homepage.t-online.de/skanthak/download/SENTINEL.DLL>
   and save it as Cabinet.dll in your "Downloads" directory, then
   copy it as Version.dll, RichEd20.dll, UXTheme.dll and DWMAPI.dll;

2. visit <https://downloadcenter.intel.com/download/26574>, download
   <https://downloadmirror.intel.com/26574/eng/Intel%20SSD%20Toolbox%20-%20v3.4.3.exe>
   and save it in your "Downloads" directory;

3. execute "Intel SSD Toolbox - v3.4.3.exe" from your "Downloads"
   directory;

4. notice the message boxes displayed from the DLLs placed in
   step 1: PWNED!


Mitigation & detection:
~~~~~~~~~~~~~~~~~~~~~~~

* NEVER run executable installers from your "Downloads" directory;

* dump/avoid executable installers, use *.MSI instead!

* see <https://skanthak.homepage.t-online.de/!execute.html> plus
  <http://blogs.technet.com/b/srd/archive/2014/05/13/load-library-safely.aspx>

* also see <https://skanthak.homepage.t-online.de/verifier.html>


Vulnerability #2:
~~~~~~~~~~~~~~~~~

On EVERY version of Windows these installers create UNSAFE
(sub)directories "%TEMP%\IIF<abcd>.tmp\", "%TEMP%\IIF<abcd>.tmp\Lang\"
and "%TEMP%\IIF<abcd>.tmp\Lang\<ll>-<CC>\", extract some dozen
DLLs "%TEMP%\IIF<abcd>.tmp\Lang\<ll>-<CC>\setup.exe.dll" and load
ALL of them with administrative privileges.

An unprivileged attacker^Wuser can replace these DLLs between their
creation and their use, again resulting in elevation of privilege.

See <https://cwe.mitre.org/data/definitions/377.html> and
<https://cwe.mitre.org/data/definitions/379.html> for this
well-known and well-documented vulnerability.


Proof of concept/demonstration:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

1. visit <https://skanthak.homepage.t-online.de/sentinel.html>,
   then download
   <https://skanthak.homepage.t-online.de/skanthak/download/SENTINEL.DLL>
   and save it in an arbitrary directory;

2. save the following batch script in the same directory:

   --- IIF.CMD ---
   :WAIT
   @If Not Exist "%TEMP%\IIF????.tmp" Goto :WAIT
   For /D %%! In ("%TEMP%\IIF????.tmp") Do Set IIFTMP=%%!
   For /R "%IIFTMP%" %%! In (setup.exe.dll) Do Copy SENTINEL.DLL "%%!"
   Set IIFTMP=
   --- EOF ---

3. start the batch script;

4. execute "Intel SSD Toolbox - v3.4.3.exe".


stay tuned
Stefan Kanthak


Timeline:
~~~~~~~~~

2017-03-06    vulnerability report sent to vendor

2017-03-06    automatic reply "we received your report"

2017-03-06    reply from vendor:
              "We will escalate this to the appropriate team and get
               back to you in the next couple of days."

2017-03-14    followup from vendor:
              "Our technical team has confirmed the finding and an
               update is being created."

2017-03-15    question sent to vendor:
              "Will all executable installers built with the
               vulnerable IIF be fixed, or just the one I picked?"

2017-03-15    reply from vendor:
              "We are getting an update from the product team this
               week and will relay your concerns."

2017-04-21    notication from vendor:
              "due to an unrelated problem we are delaying release
               until the week of May 22.  I can provide you with a
               build that has the DLL hijacking fixed if you'd like."

2017-04-21    answer to vendor: "yes, I'd like to test it!"

2017-05-04    reply from vendor:
              "we produced an official build (not beta) toward the
               May 22 release, and we are very interested for you to
               put it through your 'minefield'"

2017-05-05    notication from vendor:
              "fixed installer for the SSD toolbox available from
               <https://downloadcenter.intel.com/product/80096/Intel-SSD-Toolbox>
               and
               <https://downloadcenter.intel.com/product/80095/SSD-Software>"

2017-05-11    resent question from 2017-03-15 to vendor:
              "Will all executable installers built with the
               vulnerable IIF be fixed, or just the one I picked?"

2017-05-30    vendor publishes advisory INTEL-SA-00074
              <https://security-center.intel.com/advisory.aspx?intelid=INTEL-SA-00074&languageid=en-fr>

Powered by blists - more mailing lists