Every day we get emails from senders with attachments or with links enticing us to visit websites offering fantastic discounts or friendship with no strings attached. Most often, you can be sure the people behind these offers are out to lighten your wallet considerably. As a rule you should avoid opening mails from unknown senders with ZIP files as attachments. But if you must, head over to VirusTotal site at https://www.virustotal. com. Save the ZIP file to your desktop and upload it to the site. VirusTotal does a very good job in scanning the file and telling you whether it is infected or not.
It also gives a listing of anti-virus programs which think the file is safe and which do not. Most files can be scanned, including Windows executable, Android APKs, PDFs, images, javascript code and ZIP files. VirusTotal will not scan your entire computer. It exists just to provide a second opinion and act as a multi-antivirus scanner. I uploaded a known malicious attachment to the site and was surprised to find that several anti-virus programs did not flag the file as infected. '
You can also copy and paste the URL of a website that you feel is suspect. VirusTotal will tell you whether it is trying to scam you. For a complete analysis you should enter the URL and also do a search of the web address. Use this website whenever you are in doubt, especially when you are using a free anti-virus program which you have neglected to update for fear of paying up.
You can make the process of uploading files to the site easier by using the VirusTotal Windows Uploader. Once it is installed, all you have to do is right click on a file and choose VirusTotal from the Send To Windows menu. Files must be under 32 MB.
Sometimes even a genuine website can become malicious. A lot of advertising that you see on any site comes from third-party marketing agencies. The website owner is given a line of code that books a slot on a page. Every time a user goes to a web page, an advertisement is generated depending on the user's browsing habits. Hackers manipulate the ad network and put up ads that direct you to malicious sites. Typically they have a large 'Download' button that diverts you from the real download button on the page. This is called 'malvertising'.
Always be wary of ads that have words such as 'amazing', 'free', 'awesome'. Before clicking on such an ad, hover your mouse over the image and see where the URL is leading to. Then type the web address into VirusTotal to get it checked.
Another useful website is MXToolbox ( www.mxtoolbox.com) where you can check the validity of an email. Go to the site and click the Analyze Headers link. Paste the email header in the box on the page. In Gmail you can display the email header by opening the mail and clicking on the down arrow in the top-right corner of the message. Click on 'Show original' to display the full message headers. Email headers provide valuable information on where the mail came from and how it was routed and whether the domain it came from is blacklisted or not.
If you are a little advanced user, you must check out the excellent Internet Storm Centre at https://isc.sans.edu/. The site has very good tools for your detective work on malware and its sources.
Send in your computer-related problems to askdoss@abpmail.com with bits&bytes in the subject line
