Mozilla Firefox / Thunderbird DLL Hijacking

Type packetstorm
Reporter Stefan Kanthak
Modified 2016-04-29T00:00:00


                                            `Hi @ll  
despite better knowledge and MULTIPLE bug/vulnerability reports  
(see <>,  
<>, ...)  
Mozilla continues to ship Firefox and Thunderbird for Windows with  
a vulnerable executable installer.  
Proof of concept/demonstration:  
1. visit <>, download  
<> and save  
it as ShimEng.dll in your "Downloads" folder, then copy it as  
WinMM.dll, SetupAPI.dll, MSACM32.dll, UXTheme.dll, DWMAPI.dll,  
ShFolder.dll, RichEd20.dll, ClbCatQ.dll, COMRes.dll, Version.dll,  
SAMCli.dll, SFC.dll, SFC_OS.dll, UserEnv.dll, ProfAPI.dll, MPR.dll,  
NTMarta.dll, Secur32.dll and CryptSP.dll  
2. download any full-package installer for Firefox or Thunderbird  
from <>  
or <>  
(these are self-extractors built with 7-zip)  
3. extract setup.exe from the downloaded self-extractor and save it  
in your "Downloads" folder, for example using the command line  
7za.exe x <self-extractor> setup.exe  
(or start the downloaded self-extractor, find the temporary  
subdirectory 7z*.tmp it created below %TEMP% and copy setup.exe  
from this subdirectory to your "Downloads" folder)  
4. execute the extracted/copied setup.exe and notice the message  
boxes displayed from the DLL(s) downloaded in step 1:  
See <>,  
<> plus  
<> for the  
well-known and well-documented DLL search path vulnerability.  
Stay away from Mozilla's crapware until Mozilla starts to develop  
a sense for the basics of software engineering as well as the safety  
and security of their users^Wvictims: the authors of the 3rd party  
installer fixed these vulnerabilities about 4 months ago!  
JFTR: the vulnerable executable installer is not the only outdated  
3rd party component used to build Firefox and Thunderbird!  
Mozilla even uses different versions of this vulnerable  
executable installer for Firefox and Firefox ESR.  
See <>  
why you should NEVER name any executable (installer) setup.exe!  
stay tuned  
Stefan Kanthak  
PS: Mozilla fixed the same vulnerabilities in their executable self-  
extractor long ago (see for example  
<> or  
<>), but  
apparently did not send their fixes to the author of this tool.