Download Accelerator Plus can be tricked to download malicious file
Product(ONLY TESTED ON): Download Accelerator Plus 7.4.0.2 (unregistered)
Test Environment: Winxp Pro sp2 (patch level latest)
Risk Type: Rare exception
Threat Level: High
Vendor website:www.speedbit.com
POC screenshots: http://img482.imageshack.us/img482/4205/31uk.jpg
http://img425.imageshack.us/img425/4380/15an.jpg
speedbit.com claims to have 110 million users of DAP world wide and is one of
the popular and best download manager for windows. One of its biggest strength
to download big files in a faster connection at optimum speed is, it can
automatically search for best mirrors and download different parts of the file
form multiple location.
BUT Download Accelerator Plus(DAP) may switch its download to a un trusted or
malicious website while searching for fastest mirrors for a particular file
under certain conditions. If the ACTUAL, trusted host providing the file is
DOWN or due to network congestions the users may get and execute a malicious
file instead.
I've included two screenshots which should be self explanatory. Check out the
url?s in each screenshot and see from where the file is being received at the
end.
In the screenshot I'm trying to download 'Windows 2003 sp1' from
download.microsoft.com but DAP automatically chooses to download it only from
ftp.planet.nl as my network was having tooooooooo low internet bandwidth at
that time.
Further more, on some network/OS there might be rules for MAX CONNECTION PER
HOST and (say)if in the network someone is already downloading some file from
download.microsoft.com the outcome will surely be a VIRTUAL network
congensation for download.microsoft.com within that DMZ.
For my test I used another client computer behind the gateway to send
continuous ping ( 17 different instants) to download.microsoft.com As a result,
for my network download.microsoft.com was off the radar. So, in my another
computer DAP chooses to download Win2003 sp1 from ftp.planet.nl instead. So,
even after my network gained its full throttle... no-wounder DAP was still
downloading the file from ftp.planet.nl
My test network setup was a 3 computer PC which was left on default
configuration with Winxp sp2 (patchlevel: latest)
Changes: This advisory is slightly modified than the one that I emailed to the
vendor about a week back and tried contacting it, but with no response till now!
Result: I was receiving the file from an unknown and un-trusted source which
could be infected with a malicious program.
BUT fyi: I haven't researched on HOW and WHERE 'DAP' queries to get other
possible mirrors for the particular file.
Conclusion: I insist NOT to use download managers that does the same while
downloading important files. Or either force your download manager and check
whether the file is being downloaded from the original URL or not.
Regards,
-Bipin Gautam