Email Attachments and Risks

One of the most common tools we are using on a daily basis, is email. Due to this fact, email is also a major security problem, due to the fact that a lot of worms and trojans are using email to get into our computers.

The main problem with emails comes from using email attachments. While email attachments represent a useful addition to email functionality, as a way to send files via email, they are also risky due to the fact that email attachments can contain not just documents, but also binary attachments like executable files. Such email attachments can be dangerous as they may contain worms and trojans that can immediately infect our computers, once opened by the unsuspecting user.

There are a lot of things that one can do to protect his/her computer from the risks coming from email attachments:

- Configuring the email client used, to block opening/saving of email attachments that may have risk potential. As an example, Outlook has an option to block email attachments that are potentially dangerous.

- Use an antivirus that also has the ability to scan incoming/outgoing email. Norton Antivirus is an example of such product. The antivirus works by scanning incoming/outgoing emails, and in most cases they are able to clean up the message by removing dangerous/infected attachments, and preserving harmless content. It is very important to keep your antivirus updated on a daily basis, so you are protected from the latest worms and dangerous executables that may be sent through email attachments.

- Learn about email attachment risks. Keep informed about the latest virus threats that come via email, and how they disguise themselves in order to be opened by the unsuspecting user.

- Disable hidden file name extensions on your Windows-based computer. Some attachments may come as exacutables with a hidden extension, like .shs or .lnk for example. A virus may reach your computer as an email attachment with two extensions, for example FILENAME.TXT.shs ; due to the fact that .shs files have hidden extension on Windows computers, the user may try to open the FILENAME.TXT file which may seem harmless, but in fact he ends up executing the .shs binary file and infecting his computer in this fashion.

- Pay attention to filenames. There are lots of cases when hidden extensions are used, just like described above. Also, in some cases there are a lot of spaces inserted inside the filename, so the true extension of the file may scroll that much to the right, that we can't see it inside email client.

- Do not open any kind of email attachments that appear suspicious. Do not open any kind of executable files that are being sent to you. Some people may send you funny video files or similar things; they may even be your friends, unsuspecting that what they are sending actually contains a virus. Do not send such email attachments to your friends as well.

- Do not open email attachments from people that you do not know or you do not trust.

- Be aware that there are some files that come as email attachments in the format of zip files or other archives, in orde to trick antivirus scanners from detecting executable content. If you receive a zip file from someone you do not know, you should assume it must be dangerous.

- Be aware that Office documents like Excel spreadsheets or Word documents can be dangerous as well. Some people are actually sending emails with Office documents as attachments, even unaware that the documents they are creating and sending to you, are infected by a macro virus, which is a virus written for Office documents, since Office documents can contain hidden programs. To protect from such problems, disable macros in your Office programs.

Hopefully, these advices will prove useful to you, in protecting your computer from risks coming from email attachments, in the future.