win32:Malware-gen Avast can't find the source

Viruses and worms
1

Hi,

Running Avast 5 free edition on Windows 7.
From time to time, Avast alerts me to what seems like the creation of an exe file (with varying seemingly random names) in the windows temp directory. I’ve ran a quickscan with malwarebyte which didn’t detect anything. A full scan at boot (which took a whopping 19 -brakes for input included - hours!) with Avast removed several threats, but the problem persists after reboot. It seems svchost.exe is involved somehow, as it’s always included at the end of the listing in Avasts warnings.

Any help is greatly appreciated.

2

Check your computer for Malware with

Malwarebytes Anti-Malware 1.46 http://filehippo.com/download_malwarebytes_anti_malware/
after install click update so you have latest database before scan
click the remove selected button to quarantine anything found
you may post the scan log here

SORRY se you have already done that

follow this guide from Essexboy and post the log`s here as attachments in your next reply
http://forum.avast.com/index.php?topic=53253.0

down left corner: additional options > attach > ( OTL.Txt / Extras.Txt / MBAM scan log )

3

Thanks for the speedy reply. Here’s the logs

4

Then you can expect a reply from Essexboy sometime tomorrow. :wink:

5

ok, cheers :slight_smile:

6

Hi nothing readilly apparent there lets look deeper

Download ComboFix from one of these locations:

Link 1
Link 2

* IMPORTANT !!! Save ComboFix.exe to your Desktop

[*]Disable your AntiVirus and AntiSpyware applications, usually via a right click on the System Tray icon. They may otherwise interfere with our tools

[*]Double click on ComboFix.exe & follow the prompts.

[*]As part of it’s process, ComboFix will check to see if the Microsoft Windows Recovery Console is installed. With malware infections being as they are today, it’s strongly recommended to have this pre-installed on your machine before doing any malware removal. It will allow you to boot up into a special recovery/repair mode that will allow us to more easily help you should your computer have a problem after an attempted removal of malware.

[*]Follow the prompts to allow ComboFix to download and install the Microsoft Windows Recovery Console, and when prompted, agree to the End-User License Agreement to install the Microsoft Windows Recovery Console.

**Please note: If the Microsoft Windows Recovery Console is already installed, ComboFix will continue it’s malware removal procedures.

http://img.photobucket.com/albums/v706/ried7/RcAuto1.gif

Once the Microsoft Windows Recovery Console is installed using ComboFix, you should see the following message:

http://img.photobucket.com/albums/v706/ried7/whatnext.png

Click on Yes, to continue scanning for malware.

When finished, it shall produce a log for you. Please include the C:\ComboFix.txt in your next reply.

7

Haven’t been able to post for an hour. This is a test to see if it works now.

EDIT: Posting works but having trouble attaching the report.
EDIT II: For some reason I’m not allowed to post an attachment. Will try from my laptop.

8

Trying again from my laptop.

EDIT: And from here it worked. Something’s very wrong with my stationary ^^

9

My regular stationary PC is now suddenly flooded with trojans after I followed the steps and got the CF report generated. Avast reports finding new threats all the time…

EDIT: Ran a Malwarebyte quickscan since avast was reporting trojans every 4-5 secs. It found 3 threats, and it seems to be back to normal (as in just struggling with the Win32:Malware-gen).

10

Your user32.dll is infected - download a copy from here http://cid-32d8666f4048075b.office.live.com/self.aspx/Malware%20files/user32.dll?lc=2057 and save to your c drive i.e. C:\user32.dll

  1. Please open Notepad
    [*] Click Start , then Run[*]Type notepad .exe in the Run Box.

  2. Now copy/paste the entire content of the codebox below into the Notepad window:


Fcopy::
C:\user32.dll|c:\windows\System32\user32.dll

  1. Then in the text file go to FILE > SAVE AS and in the dropdown box select SAVE AS TYPE to ALL FILES

  2. Save the above as CFScript.txt

  3. Then drag the CFScript.txt into ComboFix.exe as depicted in the animation below. This will start ComboFix again.

http://img.photobucket.com/albums/v666/sUBs/CFScriptB-4.gif

  1. After reboot, (in case it asks to reboot), please post the following reports/logs into your next reply:
    [*]Combofix.txt [*]A new OTL log.
11

Right. No reboot was done, and here’s the logs. I still can’t post attachments from my infected computer btw.

EDIT: After the last ComboFix scan, I’m no longer getting any warnings from Avast!.

12

What error do you get when you try to upload an attachment ?

Run OTL

[*]Under the Custom Scans/Fixes box at the bottom, paste in the following

:OTL
O7 - HKU\.DEFAULT\Software\Policies\Microsoft\Internet Explorer\Control Panel present
O7 - HKU\S-1-5-18\Software\Policies\Microsoft\Internet Explorer\Control Panel present
O7 - HKU\S-1-5-19\Software\Policies\Microsoft\Internet Explorer\Control Panel present
O7 - HKU\S-1-5-20\Software\Policies\Microsoft\Internet Explorer\Control Panel present
O7 - HKU\S-1-5-21-1142471722-788857296-2053337976-1001\Software\Policies\Microsoft\Internet Explorer\Control Panel present

:Commands
[resethosts]
[purity]
[emptytemp]
[EMPTYFLASH]
[Reboot]

[*]Then click the Run Fix button at the top
[*]Let the program run unhindered, reboot the PC when it is done
[*]Open OTL again and click the Quick Scan button. Post the log it produces in your next reply.

13

This is just a test to see which errormessage I get when posting an attachment.
(So in case this is posted, please disregard the attachment :))
Hah! aparrently this is no longer an issue ^^

Coming back later tonight with the new OTL log. Thanks for great help so far :slight_smile:

14

Here’s the report from the quickscan.

BTW: Whenever I start up windows now, I have to manually start Avast and I get asked if I trust the publisher. Is there any option in Avast to set this back to auto that I haven’t found, or is this a certificate-issue ?

EDIT: I tried repairing Avast to make it autostart at startup, to no avail. Thanks though to Pondus for the tip :slight_smile:

15

The easiest way would be to download a fresh copy of Avast, uninstall the old and re-install. It may be a services/registry problem

16

Done and dusted. Avast is once again starting by itself on startup.

I’ve not gotten any warnings of the win32:Malware-gen lately. I hope that means my system is clean now.

17

I will remove my tools now and give some recommendations, but I would like you to run for 24 hours or so and come back if you have any problems

Now the best part of the day ----- Your log now appears clean

A good workman always cleans up after himself so…The following will implement some cleanup procedures as well as reset System Restore points:

Run OTL

[*]Under the Custom Scans/Fixes box at the bottom, paste in the following


:Commands
[resethosts]
[purity]
[emptytemp]
[EMPTYFLASH]
[CLEARALLRESTOREPOINTS] 
[Reboot]

[*]Then click the Run Fix button at the top
[*]Let the program run unhindered, reboot the PC when it is done

Click Start > Run and copy/paste the following bolded text into the Run box and click OK:

ComboFix /Uninstall

Run OTL and hit the cleanup button. It will remove all the programmes we have used plus itself. MBAM can be uninstalled via control panel add/remove along with ERUNT. But they may be useful tools to keep

We will now confirm that your hidden files are set to that, as some of the tools I use will change that

[*]Click Start.
[*]Open My Computer.
[*]Select the Tools menu and click Folder Options.
[*]Select the View Tab.
[*]Under the Hidden files and folders heading select Do not show hidden files and folders.
[]Click Yes to confirm.
[]Click OK.

SPRING CLEAN

Download and run Puran Disc Defragmenter

Now that you are clean, to help protect your computer in the future I recommend that you get the following free programmes:
[*]SpywareBlaster to help prevent spyware from installing in the first place.

http://img233.imageshack.us/img233/7729/mbamicontw5.gif
Malwarebytes. Run weekly to keep your system clean

It is critical to have both a firewall and anti virus to protect your system and to keep them updated.

To keep your operating system up to date visit
[*]Microsoft Windows Update

To learn more about how to protect yourself while on the internet read our little guide How did I get infected in the first place ?
Keep safe :wave:

18

Hi again.

Happy to hear my machine should be clean now.

I must say the service you guys give is excellent by any standards. Considering you’re doing this for people using a free and ad-free service just adds to the positive impression :slight_smile:

Thanks alot!

19

My pleasure - enjoy