Scan downloads automatically in Firefox
I was looking for a way to automatically scan specific file types immediately after finishing the download instead of scanning them manually before I unpacked them or started them for the first time on the system.
This way I could sort out malicious files immediately without having to worry about potentially dangerous files on my hard drive. While the local virus scanner may pick up on downloads, stored malicious files or executions as well, it may take time before it may find and identify malware.
The Firefox extension "Download Scan" sends a request to an antivirus scanner whenever a download of a certain file type has finished. The scanner will then scan the file and report back if a virus, trojan or other malicious code has been found in it.
Several options have to be configured before you can use the extension. The most important one is of course the selection of the scanner that you want to use for the scan. While this may sound complicated, it is usually not that complicated.
I'm using AntiVir as my virus scanner and had some troubles locating the correct executable for the job. After some trial and error I was able to use avcmd.exe to scan the files. I suggest you either take a look at the website / faq / helpfile of your scanner or find the right one via trial and error just like I did.
After choosing the scanner you may want to exclude certain file types from being scanned and add arguments that you want to pass to the scanner. If you want to add arguments you may need to look them up in a reference file. You may also experience issues with DOS windows not closing if the scanner is using a command line window for its scans. This can get mighty annoying if you are downloading many files throughout the day.
I suspect there must be some argument that I could add that would close the window automatically if no virus was found.
Update: Please note that the extension has not been updated since 2005 and is likely to not work anymore in recent versions of Firefox. I suggest you check out VTZilla instead which you can use to scan files directly without downloading them first. The extension has a limit of 25 Megabytes currently though which means that you cannot scan files larger than that.