Enough background - show me the malware!
Each of these screen shots can be clicked to bring up a
larger version. All were taken from a Virtual PC window running Windows
XP Service Pack 3 and fully patched as of early September 2008. Networks
sniffs were taken with Wireshark running on the host PC.
This shows the system just before infection. System.exe
was created by the malicious site and somehow executed. I tried to
replicate the drive-by download scenario but the site hosting the
initial infection had already been cleaned. On the originally infected
system, there were a few copies of this file with various extensions and
names, telling me the system tried multiple ways to make the download
and run happen. One was a screen saver, one was a media file, a .tmp
file, and others.
Once run, the background changed to a static graphic
image and the window asking you if you accept the license agreement kept
popping up. The license says you can indicate you don't agree, however
there is no button to press to actually decline and the window won't let
you move it off the screen. I moved the window around so you can see the
scary warning about your system being infected.
The rest of the background graphic -- I couldn't get a
full screen shot because the dialogue box you have to agree to won't
disappear.
The text reads:
"Warning! Win32/Adware.Virtumonde Detected on your
computer Danger!"
"Warning! Win32/PrivacyRemover.M64 Detected on your computer
Danger!"
"Please activate your antivirus software to Clean your computer"
As you will see, while there is certainly a LOT of
danger from this malware those are just meant to scare you into buying
their "Antivirus XP 2008" product. If you do buy it, I'll bet you get
more crap or just get rid of that message -- but your system will remain
infected with this or worse. There is probably also an "Antivirus XP
2009" out there now, and who knows but I'll bet they come out with
"Antivirus XP 2010"
For this particular version of the infection, a number
of processes were started. This next screen shot shows processes named
.tt7B.tmp, rld77.tmp, VMSrvc.exe, VMUSrvc.exe are the ones we can
initially see. But trust me, there are others (plus, who knows what else
this initial malware downloading application will download and install?)
Upon asking the Antivirus product to scan my system, it
pronounced that "Antivirus XP 2008 has found 1397 threats. It is
recommended to proceed with removal." Curiously, this was the EXACT same
number of threats found on the client computer I'd disinfected.
What happened behind the scenes of this infection?
Upon running the malware, the first thing this program did was phone
home. This short bit of data sniff shows two queries, one to axionaw.com
and the other to axp2008.com:
The data conversation between the target system and its
home base redirects the browser to
http://presents.axp2008.com/scan/07ae3bfbb444cd15c9548caa69d39362/16/
where the system gets the bigger malware payload. I tried it recently
and the part after "/scan/" and all those numbers appears to be just a
method of tracking who and what was downloaded, no doubt so the malware
distributors can see what methods of infection are working better than
others and thus tailor how they send out stuff to infect more people.
The exact HTML conversation looks like this:
I could show you more data how scan.exe comes into your
system, but suffice to say you are already running a program that
downloads and runs whatever the authors wanted you to run. As it is
said, "If I can get you to run my program on your computer, it isn't
your computer anymore!"
But this looks so
real -- how can you be sure it is malware and not a real antivirus
product?I've got screen shots from their
'support' page, where it is a form for email support. No phone number,
no legitimate company name, no other contact for support other than
sending email through their form.
Lets look at the registration info for the two domains
the malware phoned home to, axp2008.com and axionaw.com. There is a
utility on the internet called 'whois' that digs information about
domains from various data sources. Doing whois queries on both domains I
came up with (edited down for easier reading):
---------------
Domain Name: AXP2008.COM
Registrar: BIZCN.COM, INC.
Whois Server: whois.bizcn.com
Referral URL: http://www.bizcn.com
Status: ok
Updated Date: 10-sep-2008
Creation Date: 02-sep-2008
Expiration Date: 02-sep-2009
>>> Last update of whois database: Wed, 10 Sep 2008 07:29:46 EDT <<<
Domain name: axp2008.com
Registrant Contact:
AXP INC
Marie P. Garza info@axp2008.com
+1.318-479-6028 fax: +1.318-479-6028
1613 August Lane
Shreveport LA 71101
Created: 2008-09-02
Expires: 2009-09-02
-----------------
The phone number is disconnected. I called the day after
this domain registration was created. What is really curious is how
quickly the malware was created, pointed at this domain, distributed via
infected websites, and landed on consumer PCs. Now THAT is an effective
distribution network!
Looking at the other domain:
Domain Name: AXIONAW.COM
Registrar: ESTDOMAINS, INC.
Whois Server: whois.estdomains.com
Referral URL: http://www.estdomains.com
Name Server: NS1.AXIONAW.COM
Name Server: NS2.AXIONAW.COM
Status: clientTransferProhibited
Updated Date: 27-aug-2008
Creation Date: 27-aug-2008
Expiration Date: 27-aug-2009
>>> Last update of whois database: Wed, 10 Sep 2008 07:30:17 EDT <<<
Registrant:
Protect Details, Inc
Domain Manager (privatecontact@protectdetails.com)
29 Kompozitorov st.
Saint Petersburg
,194358
RU
Tel. +7.8129342271
Domain Name: AXIONAW.COM
Record created on 27-Aug-2008
Record expired on 27-Aug-2009
Administrator:
Protect Details, Inc
Domain Manager (privatecontact@protectdetails.com)
29 Kompozitorov st.
Saint Petersburg
,194358
RU
Tel. +7.8129342271
-------------------
[Brief update, 3/2010: All these domains now point to
privacyprotect.com - so whoever they are they decided to fly below the
radar] Does anybody reading this think sending your credit card
number to some anonymous website run by someone in Russia is a good
idea?
If you leave the system to do nothing, it goes to a
screen saver that simulates a Blue Screen of Death (BSOD) followed by a
reboot. The BSOD rotates what it displays, and this happens to be one of
the screens I captured:
Show me the cleaning!
The following walk-through is presented for your informational
purposes only. It is entirely possible that whatever malware bits
installed by this site (or others that are associated with it) have
changed what and how they work since this was detected (9/2/2008) and
written (9/10/2008). That said, I certainly do hope this helps you
either disinfect your own system because you have the same problems or
perhaps gives you clues as to what you might look for given some other
form of malware present on your system.
[4/2010 update: Actually, I no longer recommend cleaning systems and
haven't for quite awhile now. It is highly probable that even after you
completely disinfect your system from what you can see, that other
malware is still lurking around. The last thing you want to do is log
into your bank account from such an infected machine. So be safe - take
your data off, wipe the system clean, reinstall from known good media,
and put your data back on. After you read this article,
read this other article before you
decide to try cleaning it or trusting any other cleaning product /
service. Be safe. Keep your money in your own accounts.]
This was a scan I ran just before cleaning, caught in the middle to
show you the whole scary program before it comes up with its pop-up
windows you can't seem to get rid of:
With that screen running, call up task manager and get rid of the
tasks that obviously don't belong, like lphc939j0ecan.exe,
pphc939j0ecan.exe, rhcc39j0ecan.exe, VMSrvc.exe, VMUSrvc.exe, and any
others. If you've got malware that respawns when killed, you should
instead use Process Explorer from sysinternals (www.sysinternals.com,
now owned by Microsoft) and suspend the processes instead of killing
them:
With those processes dead, I found those files and deleted them.
In my case, they were in various directories, including:
C:\Program Files\Microsoft Common\
C:\Windows\system32\ <various names>
C:\Program Files\rhcc39j0ecan
If you have this infection, those file names are likely randomized
and thus different from the ones presented above. I found these by
looking in the directories and sorting by date / time and looking at the
latest files gave me most all of them in both the client and my
deliberate laboratory infections. The following screen shots show the
erasures in progress, along with the background screen that was left
over by the malware to keep me quaking in my boots that my system was
infected and I should buy their cleaning product.
Remnants of
damage left behind
After all that cleaning, I was feeling pretty confident the system
was cleaned from these threats and rebooted. This was the only screen I
saw after the boot screen:
It was a blank blue background screen with no toolbar, icons, or
anything. Apparently one of the bits of malware I'd removed was somehow
hooked into running some critical part of windows. I could hit
Ctrl-Alt-Del and come up with task manager. Looking, I couldn't find
explorer.exe running, so I tried running it manually. What came up was
an error dialogue box stating that:
"Windows cannot find 'explorer.exe'. Make sure you typed the name
correctly, and then try again. To search for a file, click the Start
button, and then click Search."
The screen is captured here:
I checked, and explorer was right where it should have been, was the
right size, and I even copied a new copy from another system in case
that program had been hacked by the malware, and still explorer would
not start. Nor would it start from the command line. Somehow (rootkit?)
that file was being redirected and not allowed to run. However, I could
copy explorer.exe to explorer1.exe and then it ran just fine. That told
me the binary was in tact, but it was somehow being mangled or
redirected.
Some strategic Internet searching lead me to a registry key that can
be used to redirect one program to another for debugging purposes. That
key's value is shown in the screen below and should be deleted.
Having copied and now running explorer1.exe, I got the desktop, start
bar, and other associated functionality back. In this screen, the key
redirects explorer.exe to instead run the program at C:\Program
Files\Microsoft Common\wuauclt.exe, which is their malware. As it turns
out, there was still some traces of malware on the system that
re-download and re-infected the system with the same malware I'd just
removed ... so for me it was lather, rinse, and repeat what I'd already
done.
For reference, the key to delete was:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image
File Execution Options\explorer.exe\Debugger
It looks like this key can be used to redirect just about any
executable to another. Very powerful. But with great power comes great
responsibility.
The next step was getting rid of various files that were run upon
startup. You can use the program autoruns, also available from
sysinternals.com or check all the various run keys manually. As the
screen shot below shows, I found them at HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run.
The key VPCUserServices is needed for the virtual machine additions and
is not part of the malware.
There are a few remnants of damage left behind -- first off, that
annoying screen telling me I'm infected. Being a background screen, it
is in the background properties pages. Except the malware disabled the
display properties and the screen saver tabs to keep its message
displaying as long as possible. By using group policy settings, anyone
can disable or enable your ability to do just about anything on your
system. On the left, screen showing the Display Properties control
panel's Display and Screen Saver tabs are missing. On the right are the
registry keys that were created to disable them.
So deleting the registry keys:
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System\NoDispBackgroundPage
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System\NoDispScrSavPage
Brings your Screen Saver and Display tabs back from the "Display
Properties" control panel dead:
And you can now change them off that awful malware reminder and onto
something more pleasant.
And so I thought I was done. Yet again. Are you sensing a pattern
here? No matter how much you do, you can never really be 100% certain
that every trace of the malware is gone -- unless you completely wipe
out the system and reinstall everything from known good media. Again I
thought I was done, and again I was wrong.
As it turns out, that system was phoning home and sending out spam
mail. Here are some network sniff traces I took while experimenting with
it. The was a fresh boot in the virtual machine. I'm giving the packet
number, followed by what is happening.
212-217: Check for internet connectivity, connect / disconnect from
google.com. If no internet, it stops.
218-226: Check if it has access to google's mail server. If it can't
send mail, it stops.
I found this by booting first with no internet connectivity, then
full connectivity, then I added a rule to the firewall to prevent this
system from sending any SMTP mail packets which I could instantly turn
on / off. Once it phoned home and got its payload, it started spamming
and I could shut down SMTP and watch all the connections get blocked at
my local firewall.
Packets 228-401 are split between the two sniff snapshots and are the
malware logging into its home base, getting its spam mail messages, who
to send the mail to, and then starting to connect to different mail
servers to actually send.
Packets 398-420 are here:
I grabbed one of the message sequences that got out of the system to
show the spam mail:
I dug around with various tools for an hour or so looking for this
piece of code. TCPView showed a process as a system service generating
all the connections, but that system service had two very legitimate
uses (the Event Log and the Plug and Play service). The DNS Cache
service was doing a lot, but that was in response to the malware making
DNS queries to find mail servers. Nothing showed up in any of the
autoruns, process monitor, or any other tool as a 'this is the malware
you are looking for' since it was somehow hiding.
When I started poking around in system drivers, I found one I
couldn't recognize and was date / time stamped at the infection time,
which I also couldn't delete as it appeared like it was in use. That
file was 3cba6cfe.sys and is pictured below. As it turns out, I booted
into safe mode and could see I wasn't sending any malware, and thus
could rename the suspected malware, which I'm doing below:
Once renamed, I booted back into normal windows mode and watched the
sniffer -- no queries were made, no connections out to the bad site
happened, and all appeared quiet on the network, so I'm thinking this
was the bad stuff.
That spam sending malware was actually a driver or service starting
up in the registry in a couple of places called "3cba6cfe.sys" (though
if you see it the name is probably different by now) -- those two places
are shown in the two screens below. Both keys were deleted with the
registry editor:
I watched the system for a few more hours and didn't see any more bad
network data, so I pronounced this re-infected virtual machine as
reasonably clean and deleted it. But I wouldn't bet my life savings on
it being 100% clean -- it could have had still more hidden stuff that
only wakes up if I log into my bank, and only then forward my login
information to someone else interested in cleaning my account.
How would you like to make it so you never have to go through
this again? Read this article on
making malware recovery easy!
------
If you found this helpful (or not), please send me a brief email -- one line
will more than do. If I see people need, want, and / or use this kind of
information that will encourage me to keep creating this kind of content.
Whereas if I never hear from anyone, then why bother?
I can be reached at:
das (at-sign) dascomputerconsultants (dot) com
Enjoy!
David Soussan
(C) 2008, 2010 DAS Computer Consultants,
LTD. All Rights Reserved.
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