13 November 2009

Be Careful with Attachments

There have been a number of really bad viruses just within the past 6 months. We've seen the W32.Beagle, W32.Netsky, MyDoom, and so on. Most of these viruses were transported or replicated from pc to pc-using email attachments. These are easy to spot if you're paying attention, simply because they are usually executable files, but not always.

Some attachments contain Macros (simple programs that run within other programs, all the titles in Microsoft Office use macros). If you're not that familiar with spotting file extensions, don't worry, that's what I'm here to talk about today. If you are a little hazy on the whole "file extension" thing then let's spend a few moments explaining it.

File extensions are what tell the program how to treat a particular piece of data. For example, most people are somewhat familiar with .doc or a .txt file extensions these are both text documents and when the user opens this file the Operating System looks at this extension and then knows how to open it.

Hackers try to use some sort of eye-grabbing ploy to get you to open their email and activate the virus, which is always an attachment. Most Anti-virus nowadays stops, or at least warns, you of these high risk attachments and even take measures to protect you. However, on the average 10-15 new viruses are created every day and I personally wouldn't count on any program to 100% protect my pc. That's why I scrutinize any email, if I wasn't expecting an attachment, I won't open it until I had a chance to talk to the sender.

Some of the more common file types used to hide viruses include:

.scr - Windows Screen Saver - USE CAUTION if you receive a screen saver via email. They can contain worms or viruses
.pif - DO NOT OPEN! This is most likely a virus. Clicking it will run a program or code that can mess up your computer.
.exe - executable file - a program that contains a virus, Trojan horse, or worm
.pps - MS PowerPoint (can contain macro virus)
.zip - Zip (compressed) file
.vbs - Visual Basic script
.bat - Executable MS-DOS batch file
.com - DOS executable command
.asp - active server page - internet script
.doc - Word document (can contain macro virus)
.xls - Excel file (can contain macro virus)

This is not a complete list. Just because an attachment may have one of these extensions doesn't mean that it is a virus, but it should send up warning flags. Hackers use clever subject lines, and viruses can appear to come from a friend so keep on your toes and don't fall victim to their deceptive traps. Scan those attachments and verify with the sender before opening.

AbhiShek SinGh
Founder of 'TheHackingArticles'. Cyber Security Analyst, Cyber Security Researcher, and Software Engineer. Follow 'AbhiShek SinGh' on Facebook , Twitter or Google+ or via Email

Subscribe to stay up to date