Necessity to scan USB Flash Memory ?

Avast Free Antivirus / Premium Security
1

Hello,
When I see that Avast perform scanning every time a file is executed, every time a file is written, every time a file is opened, I wonder if it is still necessary to scan manually a USB flash memory when we insert it into a computer.
Could you confirm it is necessary, or could we just rely on Avast security ?

Thanks for your answer.

2

It is probably more important to protect it against becoming infected, typically this will be from autorun.inf infections.

As you rightly say avast will scan any file which is run from the USB, which is a) a target of malware or b) would present an immediate risk if infected, e.g. executable files.

  1. Flash Drive Disinfector
    Information and Download Flash_Disinfector.exe by sUBs from >here< and save it to your desktop.
    [*] Double-click Flash_Disinfector.exe to run it and follow any prompts that may appear.[*] The utility may ask you to insert your flash drive and/or other removable drives including your mobile phone. Please do so and allow the utility to clean up those drives as well.[*] Wait until it has finished scanning and then exit the program.[*] Reboot your computer when done.
    Note: Flash_Disinfector will create a hidden folder named autorun.inf in each partition and every USB drive plugged in when you ran it. Don’t delete this folder…it will help protect your drives from future infection.

Mirror download site, http://download.bleepingcomputer.com/sUBs/Flash_Disinfector.exe

3

Thank you David,
in fact I already block the access to the autorun with Panda USB vaccine.
Just to know, do you personally scan a USB memory every time you plug it into your computer ?

4

No I don’t, but then again I know the origin of where they have been (my systems) are clean. If I had a suspect USB then perhaps so, but then again the resident scanner would scan any active files.

So the policy is similar to doing on-demand scans on the main system, they are much depreciated by having a resident anti-virus. For the most part on-demand scans will be scanning files that would otherwise be dormant or inert (archives).

Whether you choose to scan them based on the above information, would be down to your acceptance/avoidance of risk and if you also have a robust backup and recovery strategy.