System Intrusion

The Internet was designed to allow easy access between networked computers. Computer hackers can take advantage of this, accessing other people's computers, to cause mischief or for more serious criminal reasons.

Although computer vandalism, theft and the invasion of privacy is uncommon, it still can pose a threat.

What is system intrusion?
Computer hackers are able access the information stored on PCs, if these aren't properly protected. Hackers often do this using automated intruder programs. These programs usually look for 'Trojans' installed on people's computers.

What are Trojans?
These are a type of virus. They pretend to look like legitimate programs or utilities (e.g. a screensaver, game etc.).

What do Trojans do?
They silently destroy files or unlock a 'back door', giving a hacker easy access to your computer system and personal information. Trojans can:

• Steal private information - e.g. bank and credit card details, usernames and passwords.
• Corrupt or destroy information on your PC.
• Take control of your PC to hack into other systems.

How can a Trojan get into my PC? Trojans are usually found as executable files - attached to emails or as website downloads (e.g. mp3s, tools, or games). Be very wary of opening files with .exe, .com, .bat and .vbs extensions, unless you're certain they are harmless and come from a safe source

Also watch out for hidden file extensions. By default Windows hides the last extension of a file (e.g. what may seem to be a harmless picture - 'photo.jpg' could actually be 'photo.jpg.exe' - a Trojan).

How do I find out if I've got a Trojan? If you think that an attempt to access your PC has been made you should run a full virus check of every file on your PC. (Make sure that your virus software is up-to-date before doing this).

Securing your system – firewalls A firewall blocks unauthorised access to computers over a network, locking the door to unwanted intruders and stopping them scanning your PC.

Firewalls keep a log of the incoming and outgoing connection attempts to and from your computer. Hardware or software-based, a firewall is the ultimate tool in the defence of your system.

Home users: a software firewall is cheap and effective solution.

Business users: a hardware solution is advised as they offer the best defence.

Windows XP comes with a built-in and easy to use firewall, however, this only monitors incoming activity. Some forms of intrusion can use your computer's outgoing data, so a fully featured firewall is always the best option.

Also, PlusNet offer extra security services, such as a personal firewall solution. It is possible to download low-cost or free personal firewall programs from reliable download sites such as Tucows.

The PlusNet Usertools site is a useful website run by a group of PlusNet customers. They have created a tutorial on security software, including firewalls - Usertools: Essential security software

(Please note that while we at PlusNet are pleased to recommend the Usertools site, we are not responsible for the content located there. If you have any questions about the Usertools site you should contact the Usertools team directly)

Wireless Internet users: We recommend that you install a security solution on your device, which provides adequate protection against viruses and system intrusion. Also:

• De-activate any automatic log-in facilities (e.g. passwords).
• Where possible - use a secure Virtual Private Networking (VPN) to connect to a corporate network.
• When banking online, check for the padlock icon on your browser. Click on it, to prove that the website is genuine and secure.

Dos and Don'ts

Do
- Use a firewall. If you are using Windows XP, switch on the built-in firewall. Learn how to activate a Windows XP firewall
- Create user accounts if using recent versions of Windows (2000, XP) and assign a password to the guest account if using Windows XP to restrict access to information.
- Use a router for broadband connectivity. This makes your PC invisible to Internet users and more resistant to attack. However, firewalls can make some legitimate activities such as hosting services or network computer games more difficult.
- Consider upgrading your operating system, if you’re still using an older version of Windows. More recent versions of Windows, such as XP offer increased security and are harder for hackers to exploit.

Don't
- Use an 'Administrator' account (Windows 2000 or XP) for everyday work, try to use the ‘Limited’ account instead. Limited account users have more restricted administration rights, but you reduce the risk of it being used against you.
- Download, open or preview any file that you're not sure about. Even if files come from family or friends you need to make sure that these aren't Trojans in disguise. You should scan the attachment with your anti-virus program and if in doubt double-check with the sender what the file actually is.

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