[GUIDE] How to keep your PC safely - Tips to determine a legitimate file [TIPS]

[Vexna]

A firewall is a program that filters what travels through one network to another.



It is used to secure networks and computers, in short, control access and block what is forbidden.
We also use a firewall to protect a local network of the Internet:





Briefly, it does:

₪ Allow LAN computers to connect to the Internet.

₪ Block attempts to connect to the Internet computers on the LAN.



Each time a data packet arrives, the firewall compares the packet to every rule until it finds one that matches the packet. It runs the action corresponding to the rule.

The rules can be: the packet's destination address, source address, destination address, source port, date, time, etc..

Actions can be: deny the packet, drop the packet, accept the packet, forward the packet to another network, modify the packet headers...



Some time ago, a new type of firewall has emerged: the so-called "personal" Firewalls. They are intended for individuals who can not afford to buy a separate computer just to make a firewall.



Instead of being a separate machine, the personal firewall works directly on the computer to be protected.

Example of personal Firewalls (download link included):

₪ SoftPerfect Personal Firewall

₪ Comodo Personal Firewall

₪ BitDefender Internet Security 2012 (30 days trial)

A firewall is not an absolute weapon

Do not think your computer is 100% protected because you have a reliable and well configured firewall.

Some Trojans are able to disable personal firewalls, or even pretend to be your Internet browser to navigate to the firewall without noticing, that's why an antivirus is also very important.



An antivirus is a software that aims to detect and possibly eliminate viruses from your computer, and take steps to prevent harm.

To detect a virus, it uses several techniques. How?

The signature:

₪ This method involves analyzing the hard drive looking for the signature of the virus, which is present in the database of the software (your antivirus), if it is current and if it knows this virus. That's why a FUD file is not always detected the first time when you scan the 'suspicious file' with your antivirus or with an Online Scanner, even with VirusTotal. The signature is a piece of virus code that identifies it. This method is most used.

Heuristic analysis:

₪ This is the most powerful because it can detect any unknown viruses by your antivirus. It seeks to detect the presence of a virus by analyzing the code of an unknown program (by simulating its operation). It sometimes causes false alarms, also know as 'false positive'.

Behavior:

₪ Antivirus software continually monitors the behavior of software assets; it scans all files created and modified. In case of anomaly, it warns the user by a message. This protection is essential when you surf the internet.



When the antivirus detects a virus, there are three possible solutions.

① Repair the file:

₪ The antivirus must be able to repair a file reached, but this is not always possible.

② Delete the file:

₪ If the antivirus is not able to delete the file, you can delete it.

③ Quarantine:

₪ This is a temporary solution. The virus places the file in a safe folder on the hard drive. When the virus is able to repair the file, you can extract the file and repair it.

Free antivirus

₪ Avast! Free antivirus

₪ AVG Free

₪ Norton 360

Windows updates are published on the second Tuesday (US hour) of each month.



Windows updates are published on the second Tuesday (US hour) of each month.

This is an extremely important update which fixes several bugs and security issues that attackers exploit. Without it, I can almost guarantee that you will get infected more easily.



Windows Update is included in Control Panel. To check for updates, click the 'Start button', click 'All Programs', and then click 'Windows Update'.





If you recently downloaded a suspicious file, you can follow the steps below to know if the file is legitimate or not.

₪ File name

₪ File size

₪ File location

₪ VirusTotal or other

₪ Google.com

₪ MD5 checksum verifier



The sources above are very useful. You can know the reputation of a file, if a process is legit, and more. (Links included)

₪ ProcessLibrary

₪ File Net

₪ What is exe

₪ File Inspect

₪ Neuber

Thumbs up to Biggrodd for the GFX.

Also suggested; '[Explanation] Everything you MUST know about viruses [MUST read]'