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I've been infected with Virut. Is there any hope for me or is a reformat my only option?


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#1 EvaXephon

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Posted 06 November 2009 - 07:29 AM

I am seeking help from anyone who is familiar with this particular virus: It is called Virut.

On October 27th, my computer was infected with the Virut family of trojans. Anti-spyware scans revealed that I was infected with rootkits, backdoors, and keyloggers. I tried using anti-spyware programs to delete all infections, but many of the files I deleted kept re-appearing, and many others were unable to be removed. Eventually, logonui.exe failed to operate properly and I was unable to access my desktop at all.

I re-formatted my C:\ drive, re-installed Windows XP, and began anew. Last night, Virut returned. My computer is showing all of the signs of infection it had previously. I suspect that Virut infected executable files on my D and E drives, and laid dormant until I executed these programs.

Immediately, I began to diligently hunt down all traces of the virus on my computer. Using HijackThis and Malwarebytes' Anti-Malware, I located and deleted all programs, processes, and files until HijackThis showed no foul entries and MalwareBytes gave my computer a clean bill of health. It is still extremely likely that the virus still exists on my computer, as its nature is to infect executable files so as to resurrect and perpetuate itself.

I am extremely hesitant to reset my computer now, as I fear that logonui.exe is infected and thus I will be unable to return to my desktop if I restart my computer at this point. A small number of processes are running, there is no unexplained network activity occurring, and I can carry out business as usual; despite Virut's assured existence on my computer, it is operating fine, and so I am not motivated to reset my computer and doom myself to another re-format.

I have learned that there exist "Virut Removal Tools" but I have not been able to find very much testimony as to the success of these tools. For example, the Symantec Virut Removal Tool claims to terminate the Virut processes, delete the Virut files, repair infected files, and delete Virut's registry values. I am very tempted to boot into Safe Mode and run this miraculous tool, but I am skeptical that it cannot fulfill its promises, and I am unwilling to turn off my computer for fear that I will not be able to return to the desktop.

And so, I have come to this forum to ask the following:

1. Has the Virut family been dealt with successfully in the past? Can this collection of trojans be defeated, despite their polymorphic, parasitic nature?

2. Are the Virut Removal Tools successful or ineffective? If there is a tool capable of ending the threat, which one is the best?

3. Is it unhealthy to leave my computer on perpetually in order to evade the risk of being unable to reboot?

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#2 htv8

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Posted 06 November 2009 - 08:03 AM

Hello EvaXephon, and welcome to BleepingComputer.com.

Virut is a polymorphic file infector with IRCBot functionality which infects .exe, .scr files, downloads more malicious files to your system, and opens a back door that compromises your computer. According to this Norman White Paper Assessment of W32/Virut, some variants can infect the HOSTS file and block access to security related web sites. Virux is an even more complex file infector which can embed an iframe into the body of web-related files and infect script files (.php, .asp, and .html). When Virut creates infected files, it also creates non-functional files that are corrupted beyond repair. In many cases the infected files cannot be disinfected properly by your antivirus. When disinfection is attempted, the files become corrupted and the system may become irreparable.

The virus has a number of bugs in its code, and as a result it may misinfect a proportion of executable files [..] some W32/Virut.h infections are corrupted beyond repair.

REFERENCE: McAfee Risk Assessment and Overview of W32/Virut

There are bugs in the viral code. When the virus produces infected files, it also creates non-functional files that also contain the virus [..] Due to the damaged caused to files by virut it's possible to find repaired but corrupted files. They became corrupted by the incorrect writing of the viral code during the process of infection. undetected, corrupted files (possibly still containing part of the viral code) can also be found. this is caused by incorrectly written and non-function viral code present in these files.

REFERENCE: AVG Overview of W32/Virut

miekiemoes' Blog: Virut is back again - sigh

miekiemoes' Blog: Virut and other File infectors - Throwing in the Towel?
This kind of infection is contracted and spread by visiting remote, crack and keygen sites. These type of sites are infested with a smörgåsbord of malware and an increasing source of system infection. However, the CA Security Advisor Research Blog says they have found MySpace user pages carrying the malicious Virut URL. Either way you can end up with a computer system so badly damaged that recovery is not possible and it cannot be repaired. When that happens there is nothing you can do besides reformatting and reinstalling the OS.

[..] warez and crack web pages are being used by cybercriminals as download sites for malware related to VIRUT and VIRUX. Searches for serial numbers, cracks, and even antivirus products like Trend Micro yield malcodes that come in the form of executables or self-extracting files [..] quick links in these sites also lead to malicious files. Ads and banners are also infection vectors [..]

REFERENCE: Crack Sites Distribute VIRUX and FakeAV | Malware Blog | Trend Micro
I would counsel you to immediately disconnect this PC from the Internet and from your network if it is on a network. If you do any banking or other financial transactions on the PC or if it should contain any other sensitive information, please get to a known clean computer and change all passwords where applicable. All passwords should be changed immediately to include those used for banking, email, eBay, PayPal, online forums, etc.: you should consider them to be compromised. Do NOT change passwords or do any transactions while using the infected computer because the attacker may get the new passwords and transaction information! (If using a router, you need to reset it with a strong logon/password so the malware cannot gain control before connecting again.) Banking and credit card institutions should be notified to apprise them of your situation (possible security breach). To protect your information that may have been compromised, I recommend reading these references:
There is no guarantee this infection can be completely removed. In some instances it may have caused so much damage to your system that it cannot be completely cleaned or repaired. The malware may leave so many remnants behind that security tools cannot find them. 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. This is something I don't like to recommend normally, but in most cases it is the best solution for your safety. Reinstalling Windows without first wiping the entire hard drive with a repartition and/or format will not remove the infection. The reinstall will only overwrite the Windows files. Any malware on the system will still be there afterwards. For more information, please read these references very carefully:

If you insist on trying to fix this infection instead of following my advice to reformat and reinstall your Operating System, there are various rescue disks available from major antivirus vendors which you can try. Keep in mind, even the vendors like Kaspersky say there is no guarantee that some files will not get corrupted during the disinfection process. In the end most folks end up reformatting out of frustration after spending hours attempting to repair and remove infected files. In my opinion, the safest and easiest thing to do is just reformat and reinstall Windows.

BleepingComputer DOES NOT assume any responsibility for your attempt to repair this infection using any of the following tools. You do this at your own risk and against our advice.

These are links to antivirus vendors that offer free LiveCD or Rescue CD files that are used to boot from for repair of unbootable and damaged systems, rescue data, scan the system for virus infections. Burn it as an image to a disk to get a bootable CD. All (except Avira) are in the ISO Image file format. Avira uses an EXE that has built-in CD burning capability.If you are not sure how to burn an image, please read How to write a CD/DVD image or ISO. If you need a FREE utility to burn the ISO image, download and use ImgBurn.




My advice to you, EvaXephon, is to reformat and reinstall. Virut is a nasty and relatively new infection and no-one can promise that the fix will work completely. Again, BleepingComputer does NOT recommend that you attempt it.

I suggest you to start backup all of your valuable data/documents/pictures/movies/songs/etc.
Keep in mind, though, that with a Virut infection, there is always a chance of backed up data reinfecting your system! Do NOT backup any applications/installers and do NOT backup any executable files (*.exe), screensavers (*.scr), autorun (.ini) or script (.php, .asp, .html, .htm, .xml) files. Also avoid backing up compressed files (.zip, .cab, .rar) that have .exe or .scr files inside them as Virut can penetrate and infect these files within compressed files too.
NOTE: If you have to backup files, do so only for MS Office documents & any non-executable files. Burn them to CD/DVD. Do NOT copy files from the infected machine to your flash drive or external hard drive as they may become compromised in the process. You risk infecting the other machine!

Virut is not disinfectable. Your only option is to perform a full reformat. Do NOT attempt a repair install. It shall be a waste of time. If you do so, the infected executables remain on the machine & you shall likely trigger another bout of Virut.

If you do not know how to perform a fresh install, use these websites and read for instructions how to format and reinstall Windows:
  • MIT IS&T: Windows XP - Clean Install
  • [url="http://www.windowsreinstall.com/"]www.windowsreinstall.com


Sorry to be the bearer of bad news, but this really is your only option at this point. Should you have any questions, please feel free to ask.

Regards,

htv8

Edited by htv8, 06 November 2009 - 08:06 AM.
typo

If I have not posted back within 24 hours, feel free to send me a PM with your topic link.

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#3 htv8

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Posted 11 November 2009 - 04:31 AM

As the problem here seems to be resolved, this topic is now closed.
If you need this topic reopened, please PM a staff member and we will reopen it for you (include the address of this thread in your request). This applies to the original topic starter only. If you should have a new issue, please start a new topic. Everyone else with similar problems, please start a new topic.
If I have not posted back within 24 hours, feel free to send me a PM with your topic link.

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