While it might be fine for most users, letting your antivirus package update itself every few minutes isn’t great if you have a very small limit on your internet connection or it’s not very fast and constant updates are eating up your bandwidth, such as when using a mobile dongle on your laptop for example. It’s also true that if you disable the updates or have computers that are constantly offline and not connected to the internet for long periods or at all, the virus definitions will get badly outdated in no time and your computer becomes more vulnerable.
Also, the situation could be that you can’t get on the internet during or after a malware attack to update the antivirus signatures. They need to be as up to date as possible to have the best chance of removing the threats. Of course, if your computer is severely infected, you may have to resort to an Antivirus rescue CD from your favorite security company.
Fortunately for most of us, many of the antivirus companies provide offline virus definition signatures so you can download them from another computer and then manually install the updates on computers with a limited or no internet connection at all.
Avast! VPS Definitions
This downloaded file will update versions 5-8 of any avast! product and there’s a separate download for anyone on the older v4. Usually a new update is released daily. The file comes as an executable you run to update the virus definitions.
AVG Bin Virus Definitions
AVG has separate update files for the free antivirus and their paid products. Download the Bin file, open the AVG main program and go to the Options menu -> Update from Directory. Then locate the bin file in the requester dialog. The module files on the download page can also update the AVG scanning engine or all of the program’s components while offline.
Avira VDF Package Generator
You cannot download the Avira virus definitions directly, but instead download a tool called the Fusebundle Generator. Run this and it downloads the latest signatures and then packs them into vdf_fusebundle.zip in the Install folder. To import the file into the Avira program, go to the Update menu -> Manual Update and locate the Zip file. There is a helpful slideshow on the download page.
Bitdefender Weekly Updates
Bitdefender updates its offline definition files once a week on a Friday so they could be a nearly week out of date depending what day you download them. The file comes as a setup installer so you just need to run it and the updates will be installed, make sure to get the correct 32-bit or 64-bit version for the operating system Bitdefender is installed on.
ClamWin / ClamAV Virus Database
Clam has 2 definition files you can download although the main.cvd is updated far less frequently than the daily.cvd which is the more important download of the two. Download the daily file (or both) and put it in the default folder of “C:\Documents and Settings\All Users\.clamwin\db” for Windows XP, or for Vista and 7 place it in “C:\ProgramData\.clamwin\db”.
Comodo Complete Antivirus Database
The complete database of the Comodo definitions is updated every couple of days, check the Summary date for the last update. Some older versions of the software need to extract the Base with 7-Zip. The safest way to update is in Safe Mode and the Base.cav file has to be copied to:
C:\Program files\Comodo\Comodo internet security\scanners
On the next page there is manual update information for several more products including Kaspersky, Norton, Microsoft and F-Secure etc.
F-Secure Virus Definition Databases
The F-Secure download page has definition downloads for Windows, Linux and an update for the rescue CD, but you need to download the fsdbupdate9.exe under the “Manual Update Using fsdbupdate: Windows” heading. Run the executable upon getting it to update Antivirus, Spyware, Spam, Parental control definitions.
Kaspersky Antivirus / Internet Security / Pure Updates
Updating a Kaspersky product offline isn’t quite as easy as some of the other competitor’s software, although luckily it isn’t too difficult. First you need to download the zip file for your specific product, for KAV or KIS go to section 3 -> step 1 for the link, for Pure go to Step by Step instructions -> step 1.
Then when you have extracted the zip, run the Updater.bat file and wait for the definitions to download, there is no progress meter so you will have to be patient as it’s a big download of around 400MB and the Command Prompt window will close when it’s finished. After that, you need to go into your software’s settings and choose to update the sources manually. Full instructions are on the download pages.
McAfee Virus Definition Updates
Updating a McAfee product is pretty straightforward and you simply download the DAT executable file from the website, run it then follow any on screen instructions. The SuperDAT definition file contains the virus definitions and the latest antivirus engine update.
Microsoft Security Essentials / Windows 8 Defender
The update file for Security Essentials / Win 8 Defender is an easy one to update because it simply comes in the form of an executable file which will install the update automatically when you run it. Make sure to click on the correct link to download the 32-bit or 64-bit version that matches the Windows you want to install it on.
Sophos virus identity (IDE) files
The Sophos definition files are compatible with versions of Sophos Antivirus not older than 3 months, and can be downloaded as either Zip or self extracting executable. Oddly it says you can’t use the self extracting files with Windows 2003 or Vista.
Symantec / Norton Security Products
The Norton virus definitions update page has update files for a number of products including the consumer Antivirus / Internet Security / 360 and the business Endpoint Protection and Antivirus Corporate, so make sure you download the correct one for your package. Note the 64-bit version of the update file is under the 32-bit version on the page. Simply run the downloaded executable to update your definitions.
Trend Micro Offline Pattern Files
There are a number of pattern files displayed on the download page, but the top most Consumer Pattern is all that’s needed to get your antivirus definitions up to date. Download the file and unzip it to “C:\Program Files\Trend Micro\Internet Security”. Then restart your computer for the new file to be recognized.
ESET NOD32 and Norman products don’t offer offline virus definition signature updates. So if you’re going to install an antivirus on a computer that has a limited Internet connection, do not go for NOD32 and Norman. Panda requires you to enter your username and password to access the database download which you’ll need to know in advance.