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Large infection by expiro virus


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#1 Khorden

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Posted 23 September 2014 - 03:41 AM

Hello everyone,
I have AVG antivirus, yesterday it detected a huge infection by expiro. The scan found about 2,000 files infected, asked me to reboot but avg alert windows are still popping up because of the expiro infection.

My SO is Windows 7 Home Premium, I have 2 internal HDD and 1 external. Checking the files in the scan report it seems that the infection is quite everywhere.

Can you please help me?

Thanks a lot.



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#2 TB-Psychotic

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Posted 23 September 2014 - 09:18 AM

I'm afraid I have very bad news. Your system is infected with a nasty variant of Virut, a dangerous polymorphic file infector with IRCBot functionality which infects .exe, .scr 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. -- 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? 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. Other variants of virut can even penetrate and infect .exe files within compressed files (.zip, .cab, rar). The Virux and Win32/Virut.17408 variants are an even more complex file infectors which can embed an iframe into the body of web-related files and infect script files (.php, .asp, .htm, .html, .xml). When Virut creates infected files, it also creates non-functional files that are corrupted beyond repair and in some instances can disable Windows File Protection. In many cases the infected files cannot be disinfected properly by your anti-virus. When disinfection is attempted, the files become corrupted and the system may become irreparable. The longer virut remains on a computer, the more critical system files will become infected and corrupt so the degree of damage can vary.

The virus disables Windows File Protection by injecting code into the "winlogon.exe" process that patches system code in memory.
CA Virus detail of W32/Virut

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.
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.
AVG Overview of W32/Virut Virut is commonly spread via a flash drive (usb, pen, thumb, jump) infection using RUNDLL32.EXE and other malicious files. It 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.

...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...
Keygen and Crack Sites Distribute VIRUX and FakeAV However, the CA Security Advisor Research Blog 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. Since virut is not effectively disinfectable, 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. In many cases the infected files (which could number in the thousands) cannot be deleted and anti-malware scanners cannot disinfect them properly. 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 reformat and reinstall the OS. 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. 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 Khorden

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Posted 23 September 2014 - 05:15 PM

First, thank you for responding.
But how can you do such a statement without any log file or scan report?


Edited by Khorden, 23 September 2014 - 05:45 PM.


#4 TB-Psychotic

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Posted 24 September 2014 - 07:21 AM

There is no way of a safe removal for this virus.

It injects istself into any .exe file (as you can see in your logs already...) and spreads using multiple ways.

 

Please read my last reply carefully - the only safe way to get rid of a file infection trojan is to wipe the disk.


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#5 TB-Psychotic

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Posted 13 October 2014 - 08:06 AM

Due to the lack of feedback, this topic is now closed.

In the event you still have problems, please send me or any Moderator a Private Message and ask them to reopen this topic within the next 5 days.

Please include a link to your topic in the Private Message. Thank you.
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