It’s a well known fact that you need to have your Anti Virus software up to date in order to be protected from latest viruses and other malware. Most security software vendors tend to provide updates over the internet. But what if you have a computer that is not connected to the internet or is having limited internet connectivity (low bandwidth, data cap, etc)? This article describes how you can update your Anti Virus software manually using offline definition updates.
Although most Anti Virus software have a built in automatic updates feature, vendors tend to release standalone update installers usually through their official website. Once you download one of these offline installers, you can use it to update virus definition files even on Anti Virus software installed on computers without internet access (Ex- Download offline installer from work computer which has internet access and then use the installer to update home computer which is not connected to the internet). Below is a list of locations where you can find and download offline definition update installers for several popular Anti Virus software.
1. Kaspersky Internet Security and Kaspersky Anti Virus 
Offline updates for Kaspersky version 5, 6 and version 7 products can be downloaded from this page. If you are using the new Kaspersky Anti Virus 2009 or Kaspersky Internet Security 2009 products, there is a separate procedure you need to follow. A complete tutorial on how to update Kaspersky 2009 (version 8.0) products offline can be found here.
2. AVG 
These offline definition updates are for the free version of AVG. AVG 7.5 offline updates can be downloaded from this page while AVG 8.0 definition updates can be found here.
3. Mcafee 
Note that not all of Mcafee’s Anti Virus products support offline updating. I’m not sure if products such as Mcafee Total Protection 2009 can be updated offline. However, updating some versions such as VirusScan Enterprise 8.5i/8.7i is possible. You can download the latest virus definition .DAT files from this page.
Note: DAT files are definition updates, SUPERDAT files are definition + scan engine updates
4. BitDefender 
Although many people don’t know, BitDefender releases offline updates for almost all of its security products including BitDefender Internet Security 2009. All of these updates can be downloaded from this page.
5. Symantec/Norton security products 
Most Norton Anti Virus products and Symantec Anti Virus products including corporate versions can be updated offline. Visit this page and choose your product under ‘Download Definitions by Product’ option.
6. Trend Micro 
Trend Micro offers pattern files to update a number of security products offline including Trend Micro Internet Security. Latest pattern files and installers can be obtained form this page.
7. Sophos 
Sophos definition files are called Virus Identity Files (IDE) - self extracting zip files with latest IDE files are released regularly. You can download them from here. Note that Sophos products older than 3 months cannot be updated offline.
8. F-Secure 
F-Secure regularly releases a file named latest.zip which includes the newest virus definition files. You can download and use this file to update your F-Secure security product manually. The most current version of latest.zip and a tutorial on how to manually update can be found on this page.
9. Avast 
Only 4.X versions of Avast! can be updated offline. You can download the iAVS utility which will update your Avast! product automatically. Latest iAVS can be freely downloaded from this page.
10. Avira 
A number of Avira products such as Avira Antivir Windows Professional, Avira AntiVir Premium and Avira Premium Security Suite can be updated offline using the VDF update. You can download latest offline definition files for Avira from here.
If your favorite anti virus software is not listed above, please let us know via a comment. We will try to find an offline updates source for it and update the article if we manage to find one.
