May 23, 2013

Using command prompt "attrib" to check for Viruses or Malware

Microsoft Command Prompt "attrib" is a very useful tool to check if your hard drives even your flashdisks have been infected by a virus.
You will know if a Malware is inside your hard drive just by looking at the attributes of each files and the file that has the attributes of +s +h +r
The function of attrib is to set and remove file attributes (read-only, archive, system and hidden).

Launch attrib

To start attrib
  1. Go to Start Menu > Run
  2. Type cmd (cmd stands for command prompt)
  3. Press Enter key
The Command Prompt will appear showing us where is our location in the directory.

 command prompt showing the current location in the directory

Using attrib

To use attrib
  1. Go to the root directory first by typing cd\(because this is always the target of Malware / Virus)
2. Type attrib and press Enter key

after typing attrib, all the attributes of all the files (excluding folders) will be shown
In this example, I have two files that are considered as malware.
Note that there are two files which I outlined in red (SilentSoftech.exe and autorun.inf). Since you cannot see this file nor delete it (because the attributes that was set on these files are +s +h +r)
  1. +s - meaning it is a system file (which also means that you cannot delete it just by using the delete command)
  2. +h - means it is hidden (so you cannot delete it)
  3. +r - means it is a read only file ( which also means that you cannot delete it just by using the delete command)
Now we need to set the attributes of autorun.inf to -s -h -r (so that we can manually delete it)
  1. Type attrib -s -h -r autorun.inf ( be sure to include -s -h -r because you cannot change the attributes using only -s or -h or -r alone)
  2. Type attrib again to check if your changes have been commited
  3. If the autorun.inf file has no more attributes, you can now delete it by typing del autorun.inf
  4. Since SilentSoftech.exe is a malware you can remove its attributes by doing step 1 and step 3(just change the filename) ex. attrib -s -h -r silentsoftech.exe

a) I typed the attrib command with the -s -h -r setting b) the result after I pressed enter - autorun.inf has no attributes left
There you have it!!!!
NOTE : when autorun.inf keeps coming back even if you already deleted it, be sure to check your Task Manager by pressing CTRL + ALT + DELETE ( a virus is still running as a process thats why you cannot delete it. KILL the process first by selecting it and clicking End Process.
NOTE: You can also apply the attrib -s -h -r command to all the partition of your computer, drive D: drive E: drive F: (all of your drives). For example. for drive D, just type "D:" (minus the double quote) then you can see that your current drive is D.. type there the command "attrib -s -h -r *.exe" for exe files and "attrib -s -h -r *.inf" and then delete the file by "del autorun.inf".

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