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TDSSC killer coming up with suspicious after trojan clean


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#1 splink

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Posted 19 February 2017 - 02:19 AM

Hi there,

 

I got a trojan a few days ago : Crypt.Xpack.Gen5 (and possibly Ramnit)

 

I ran the following (they were not all installed at the same time - I did them one by one):

 

Avira AV

Malware Bytes AV

ClamWin (this scan said the virus was a Ramnit Trojan)

Superspyware

Adw Cleaner

Tdssc Killer

 

I then restored Windows (OS = Windows 10) to a restore point, wiping all my data, and ran them all again (all clean except TDSSC - see below) before restoring a 2nd time. I believe I got rid of the Trojan.

 

When TDSSC ran at all 3 stages, it said that I had 2 suspicious files:

 

Fastboot        C:\Windows\system32\DRIVERS\Fastboot.sys
11:16:37.0018 0x17d0  Fastboot - detected UnsignedFile.Multi.Generic ( 1 )
 
FBFsmon.sys C:\Windows\system32\DRIVERS\FBFsmon.sys
11:16:43.0206 0x17d0  FBFsmon - detected UnsignedFile.Multi.Generic ( 1 )
 
I uploaded these files to Virus total and they came back clean.
 
The question I have is - am I clean?
 
Further note: when I restored windows, it said it could not delete all my personal files - something called windows.old stayed. I have since cleared this using disk cleanup
 
Even further note: the pc is still a bit slow.
 

Thank you in advance for any help you can offer.


Edited by splink, 19 February 2017 - 02:22 AM.


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#2 boopme

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Posted 02 March 2017 - 12:07 PM

I'm afraid I have very bad news.

Win32/Ramnit (and related variants) is a dangerous file infector with IRCBot functionality which infects .exe, and .HTML/HTM files, and opens a back door that compromises your computer. Using this backdoor, a remote attacker can access and instruct the infected computer to download and execute more malicious files. The infected .HTML or .HTM files may be detected as Virus:VBS/Ramnit.A or VBS/Generic. Win32/Ramnit.A!dll is a related file infector often seen with this infection. It too has IRCBot functionality which infects .exe, .dll and .HTML/HTM files and opens a back door that compromises your computer. This component is injected into the default web browser by Worm:Win32/Ramnit.A which is dropped by a Ramnit infected executable file.

-- Note: As with most malware infections, the threat name may be different depending on the anti-virus or anti-malware program which detected it. Each security vendor uses their own naming conventions to identify various types of malware.With this particular infection the safest solution and only sure way to remove it effectively is to reformat and reinstall the OS.

Why? The malware injects code in legitimate files similar to the Virut virus and in many cases the infected files (which could number in the thousands) cannot be disinfected properly by your anti-virus. When disinfection is attempted, the files often become corrupted and the system may become unstable or irreparable. The longer Ramnit.A remains on a computer, the more files it infects and corrupts so the degree of damage can vary.

Ramnit is commonly spread via a flash drive (usb, pen, thumb, jump) infection where it copies Worm:Win32/Ramnit.A with a random file name. The infection is often contracted by visiting remote, crack and keygen sites. These type of sites are infested with a smörgåsbord of malware and a major source of system infection. However, a variant called the Ramnit worm targets Facebook users....can bypass two-factor authentication and transaction signing systems, gain remote access to financial institutions and compromise online banking.

In my opinion, Ramnit is not effectively disinfectable, so your best option is to perform a full reformat as there is no guarantee this infection can be completely removed. In most instances it may have caused so much damage to your system files that it cannot be completely cleaned or repaired. Security vendors that claim to be able to remove file infectors cannot guarantee that all traces of it will be removed as they may not find all the remnants. If something goes awry during the malware removal process there is always a risk the computer may become unstable or unbootable and you could loose access to all your data.

Further, your machine has likely been compromised by the backdoor Trojan and there is no way to be sure the computer can ever be trusted again. It is dangerous and incorrect to assume the computer is secure even if your anti-virus reports that the malware appears to have been removed.

Many experts in the security community believe that once infected with this type of malware, the best course of action is to wipe the drive clean, reformat and reinstall the OS. Please read:

Whenever a system has been compromised by a backdoor payload, it is impossible to know if or how much the backdoor has been used to affect your system...There are only a few ways to return a compromised system to a confident security configuration. These include:
• Reimaging the system
• Restoring the entire system using a full system backup from before the backdoor infection
• Reformatting and reinstalling the system

Backdoors and What They Mean to You

This is what security expert miekiemoes has to say: Virut and other File infectors - Throwing in the Towel?

If I guide someone with Virut (or any other File Infector) present and their Antivirus cannot properly disinfect it, then I recommend a format and reinstall...dealing with such infections is a waste of time and that's why I prefer the fastest and safest solution - which is a format and reinstall...After all, I think it would be irresponsible to let the malware "stew" (download/spread/run more malware) for another couple of days/weeks if you already know it's a lost case.

This is what Jesper M. Johansson at Microsoft TechNet has to say: Help: I Got Hacked. Now What Do I Do?.

The only way to clean a compromised system is to flatten and rebuild. That’s right. If you have a system that has been completely compromised, the only thing you can do is to flatten the system (reformat the system disk) and rebuild it from scratch (reinstall Windows and your applications).



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#3 splink

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Posted 03 March 2017 - 07:27 PM

Thank you.

 

So doing system restore doesn't count as a reformat?



#4 boopme

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Posted 04 March 2017 - 10:07 AM

No that only returns your machine back to a specific time.


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