Executable installers are vulnerable^WEVIL (case 31): MalwareBytes' installers allows arbitrary (remote) code execution WITH escalation of privilege Mar 06 2016 07:29PM
Stefan Kanthak (stefan kanthak nexgo de)
Hi @ll,

Malwarebytes executable installers mbam-setup-
and mbae-setup- (available from
<https://downloads.malwarebytes.org/file/mbam_current/> and
<https://downloads.malwarebytes.org/file/mbae_current/>) load
and execute UXTheme.dll and DWMAPI.dll from their "application

For software downloaded with a web browser the application
directory is typically the user's "Downloads" directory: see
and <http://seclists.org/fulldisclosure/2012/Aug/134>

If an attacker places UXTheme.dll and/or DWMAPI.dll in the user's
"Downloads" directory, for example per "drive-by download" or
"social engineering", this vulnerability becomes a remote code

Due to the application manifest embedded in the executables which
specifies "requireAdministrator" the executable installers are run
with administrative privileges ("protected" administrators are
prompted for consent, unprivileged standard users are prompted for
an administrator password); execution of the DLLs therefore results
in an escalation of privilege!

Proof of concept/demonstration:

1. visit <http://home.arcor.de/skanthak/sentinel.html>, download
<http://home.arcor.de/skanthak/download/SENTINEL.DLL>, save it
as UXTheme.dll in your "Downloads" directory, then copy it as

2. download mbam-setup- and mbae-setup-
and save them in your "Downloads" directory;

3. execute mbam-setup- and mbae-setup-
from your "Downloads" directory;

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


See <http://seclists.org/fulldisclosure/2015/Nov/101>,
<http://seclists.org/fulldisclosure/2015/Dec/86> and
http://seclists.org/fulldisclosure/2015/Dec/33 plus
<http://home.arcor.de/skanthak/!execute.html> and
<http://home.arcor.de/skanthak/sentinel.html> for details about
this well-known and well-documented BEGINNER'S error!

Stefan Kanthak

PS: I really LOVE (security) software with such trivial beginner's
errors. It's a tell-tale sign to stay away from this snakeoil!


2015-12-25 sent report regarding MBAM to vendor

2015-12-25 automatic reply from vendor:
"We have received your request and an agent will respond
to your ticket in the order in which it was received."

2016-01-03 reply from vendor:
"We'll take this into consideration for a near-future
installer revamp."

2016-02-02 requested status update

NO REPLY, not even an acknowledgement of receipt

2016-02-02 sent notice to Marcin Kleczynski after his public
announcement of a bug bounty program

2016-02-02 reply from Marcin Kleczynski:
"I'm copying Pedro Bustamante who organizes our bug
bounty program to take a look."

NO reply from Pedro Bustamante et.al.

2016-02-12 sent report regarding MBAE to vendor

NO REPLY, not even an acknowledgement of receipt

2016-02-22 resent report regarding MBAE to vendor

NO REPLY, not even an acknowledgement of receipt

2016-03-06 report published in accordance with my disclosure
policy <http://home.arcor.de/skanthak/policy.html>

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