Malwarebytes DLL Hijacking

Type packetstorm
Reporter Stefan Kanthak
Modified 2016-03-07T00:00:00


                                            `Hi @ll,  
Malwarebytes executable installers mbam-setup-  
and mbae-setup- (available from  
<> and  
<>) 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 <>  
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 <>, download  
<>, 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 <>,  
<> and plus  
<!execute.html> and  
<> 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  
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 <>