31 March 2009

Malware or legitimate?

by Roger Karlsson

Are you struggling to figure out if a file listed in FreeFixer's File Database is malware or a legitimate file that you want to keep on your computer? Hopefully this guide will help you:

Comparing two files, side by side

Let's look at firefox.exe, which is a legitimate file, and compare it to olhrwef.exe which is malware. These two files are great candidates for typical legitimate and malware behaviour:

firefox.exe

firefox.exe was added to FreeFixer's database on the 30 Mar 2009. The most recent search for this file was done on 30 Mar 2009. firefox.exe is located in the 'C:\Program Files\Mozilla Firefox\' folder and has a size of 307704 bytes.

So far there has been 2 searches for firefox.exe.

olhrwef.exe

olhrwef.exe was added to FreeFixer's database on the 13 Mar 2009. The most recent search for this file was done on 13 Mar 2009. olhrwef.exe is located in the 'C:\WINDOWS\system32\' folder and has a size of 106199 bytes.

So far there has been 1 search for olhrwef.exe.

File names and folder information is what appears on top for each file in the file database. Legitimate software developers give their files meaningful names that users recognize, while many malware programs use names that seems to be a number of randomized letters. Malware use this technique to avoid detection based on filenames. Legitimate programs are in most cases installed under 'C:\Program Files\', while malware has a tendency to end up in the Windows system directory 'C:\WINDOWS\system32\'. Please keep in might that there is nothing that prevent a malware author from giving their files meaningful names, or even the same name as another legitimate file.

Now, let's have a look at the version information for firefox.exe and olhrwef.exe:

Vendor and version information

The following is the available information for firefox.exe:

Property	Value
Product name	Firefox
Company name	Mozilla Corporation
File description	Firefox
Internal name	Firefox
Original filename	firefox.exe
Legal copyright	©Firefox and Mozilla Developers, according to the MPL 1.1/GPL 2.0/LGPL 2.1 licenses, as applicable.
Legal trademark	Firefox is a Trademark of The Mozilla Foundation.
Product version	3.0.8
File version	1.9.0.8

Vendor and version information

This file does not have any version or vendor information.

The vast majority of legitimate software developers take the time to fill in the version and vendor data for each file in their product, which the developers of Firefox have done. Version information is missing for olhrwef.exe, which I would say is typical malware behaviour. But keep in mind that there is nothing that stops a malware author from adding version information that seems legitimate. Also keep in mind that there are a few cases where legitimate software is missing version information.

Digital signatures

This file has a valid digital signature.

Property	Value
Signer name	Mozilla Corporation
Certificate issuer name	Thawte Code Signing CA
Certificate serial number	1ee2bfb90ae659c80cb7ea4c606ff03e

Digital signatures

This file is not signed.

The digital signature is a great tool for determining if a file is legitimate. Nowadays many of the big software publishers, such as Microsoft, Adobe and Google are signing their files. firefox.exe has a valid digital signature, which means that firefox.exe files comes from the company/person listed as "Signer name", in this case the Mozilla Corporation. A valid digital signature also implies that no one has manipulated the file in any way. The absence of a digital signature does however not imply that the file is malicious. Many small scale software developers, like myself, does not yet sign files.

Now you should have a pretty good idea if the file on your computer is legitimate of malware, but there is more you can do:

Using the online virus scanners

There are a few great free online services that will scan suspicious files. I highly recommend using these online scanners to further investigate the files on your computer. These scanners will run the file through a big number of anti-virus engines:

Well, now you have loads of information to determine if that file on your computer is malware or legitimate. Me and all other FreeFixer users would greatly appreciate if you share your findings by posting comments or voting on the thumb up icon keep / thumb down icon remove polls for each file you investigate. Thank you!

Comments

Craig Barbre writes

0 thumbs

I found your web site very informative and much easier to understand than other sites,it is also straight forward and to the point. thanks I WILL recommend it to others in need. thanks again Craig

# 26 May 2009, 4:07

Roger Karlsson writes

1 thumb

@Craig Thank you!

# 27 May 2009, 2:12

Lance writes

-2 thumbs

Hi i need to download keenfinder.exe because every time i open my computer an error box appears saying keenfinder.exe not found. Please help me to fix this. Thanks

# 6 Jun 2009, 7:01

stacie writes

2 thumbs

Thank this was very helpful.

# 18 Jun 2009, 21:58

Roger Karlsson writes

-1 thumb

@Lance: Keenfinder.exe is a program that redirects you to keenfinder.com if you type in a search in the browser's address bar. Keenfinder is sometimes referred to as Adware.Onestep.

More information on Keenfinder.exe is available here:

http://www.freefixer.com/library/file/30422/

# 1 Jul 2009, 1:21

Jim Vermillion writes

-1 thumb

Thank you for the labor of love that you have invested in this very informative, clear and understandable site. You answered my need. I am very grateful.

I live only by the grace of GOD in His Beloved Son JESUS who came into the world to save sinners, even tjhe worst. Praise be to HIM forever.

Jim Vermillion

# 5 Aug 2009, 11:54

Helen Long writes

0 thumbs

THANKS for your helpful website! I'm not sure about a file named ld12 that just began appearing as an error as I was shutting down my pc yesterday, and again this a.m., after an Avast antivirus update was installed. The error made me wonder what this file (new to me) was for so searched Google and found your review. I deleted it and now hope it isn't one I may need somewhere. Does anyone have info on it, or suggestions of where else to look?

# 19 Aug 2009, 8:21

Chiku writes

-2 thumbs

Thanx A trillion my PC ws actin up n i js dwnldd FF n im strting 2 remve tha shyza'z as u cn tell by my spellcheck-less message im a youngin and im gna halla 2 ma peepz bout this... cheers mate...1

# 19 Aug 2009, 15:12

Holly Stallings writes

2 thumbs

Your website gets 5 *'s from me. I can actually understand what your talking about. This is going on my favorites list. I would put it in my google bookmarks, but for some reason my booksmarks and my form filler disappear everytime I download the google toolbar. I even made google my homepage, but those two things are gone.

# 29 Aug 2009, 16:19

Pchopat writes

0 thumbs

Hello folks and thanks to the person who brought that information to all of us. Here is my question. I am using Webroot spy sweeper for cleaning viruses and other harmful n suspicous files. So far i am so happy about the work of that small and not that famous anti-viruses program. However recently i don't know how but i catch on my pc an adware which pops up so many different advertisments which kill the speed of my pc. So when i ran the program it finds that adware but when i put in quaranteen i still receive those pops up advertisments. Hope you can give me some advices which program will it help me because i have tried the famous anti-viruses programs and i end with the conclusion that there is no any anti-viruses program which can find all of the harmful files and viruses.

Thanks for you help and advices

# 29 Aug 2009, 16:43

manawizard writes

0 thumbs

Pchopat

try http://www.malwarebytes.org

hope this helps your situation.

# 29 Aug 2009, 17:57

Shawinds writes

0 thumbs

Your wonderful site has now been bookmarked...wonderful clear information that actually answers my questions..Refreshing!! Thanks

# 1 Sep 2009, 5:06

Roger Karlsson writes

0 thumbs

@Pchopat: You can also give FreeFixer a try. It scans many locations where unwanted software has a known record of appearing or leaving traces. More info here:

http://www.freefixer.com/

# 1 Sep 2009, 9:38

Åsa Möller writes

0 thumbs

En bra sida och jag hoppas att jag har fått hjälp.

# 19 Oct 2009, 8:35

jim writes

0 thumbs

seems pretty good so far i will test it further. also good is old macdonalds farm auto eater and spybot search and destroy both free programs ... the auto eater stops the malware from executing .. spybot is not good at removing all malware

# 7 Nov 2009, 18:16

Mahesh writes

0 thumbs

i am having the error of MSVMCLS64.exe what is this and why do it occur?

having problem.

thanks

# 10 Dec 2009, 2:41

Roger Karlsson writes

0 thumbs

@Mahesh: msvmcls64.exe looks like malware to me. What does the error message say? Please post here:

http://www.freefixer.com/library/file/46046/

# 10 Dec 2009, 3:07

Jonas writes

-1 thumb

is yahooservice.AU a virus? or will it Block me from going in my E-mail if I block access?

# 14 Dec 2009, 2:28

Jackson writes

0 thumbs

My virus software has told me that I have an infected file c:\windows/system32/sshnas.dll. I cannot find this file anywhere. Is it a legitimate file that is infected or a malware file?

# 20 Dec 2009, 14:45

Roger Karlsson writes

0 thumbs

@jackson: sshnas.dll is a malware file. You can find more info about it here:
http://www.freefixer.com/library/file/45164/

# 20 Dec 2009, 19:37

Brian Van Hoose writes

1 thumb

I just happened to be cleaning out my Temp folder when I came across several files that I didn't recognize. This site provided information on the files in question in a way that was clear. I was able to feel comfortable with my decision to delete the files.

Thanks for providing this service.

# 18 Feb 2010, 12:14

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31 March 2009

Malware or legitimate?

by Roger Karlsson

Comparing two files, side by side

firefox.exe

olhrwef.exe

Vendor and version information

Vendor and version information

Digital signatures

Digital signatures

Using the online virus scanners

Comments

Craig Barbre writes

Roger Karlsson writes

Lance writes

stacie writes

Roger Karlsson writes

Jim Vermillion writes

Helen Long writes

Chiku writes

Holly Stallings writes

Pchopat writes

manawizard writes

Shawinds writes

Roger Karlsson writes

Åsa Möller writes

jim writes

Mahesh writes

Roger Karlsson writes

Jonas writes

Jackson writes

Roger Karlsson writes

Brian Van Hoose writes

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