Security

Ask something
Discussion Locked

General Question about security

0 helpful
11 replies

by Member 25073181 1 view

Closed to new repliesThis discussion is closed. It stays readable, but it takes no new replies.

Hi everyone
I am wondering if anyone can either answer this for me and/or point in the direction of any available online resources.

In a NT network that is connected to the internet, does leaving an open browser idle for a period of time (we have users leaving them open all day) cause issues in terms of security or bandwidth usage?

In terms of security, I would imagine that leaving a browser open (and therefore an open port 80 on that machine) could potentially leave that machine vunerable to an attack?

In terms of bandwidth usage, I would think that if the browser is sitting idle, no bandwidth would be used (no network traffic going to or from the machine), unless the user left the browser at a page containing an ad banner that auto changed on a time period basis?

If anyone could confirm or clarify these above points, that would be much appreciated

Thanks in advance

Daryl
daryl_s@iprimus.com.au

11 replies

by xpertdragon

In an NT Network, like Windows95,98 and NT Workstation connecting to a NT Server doamin to get their outside internet connection most likely always have Port 80 (common web port) open from the time many network services are started upon boot up of aworkstation machine. If you are concerned about general web security, there is only so much you can do in monitoring a users web traffic, unless you are in a strict work environment. If you are in the common desktop environment of Internet Explorer, I would recommend keeping up to date with Security bulletins, Security threats, and possible patches you can apply. You can do this by subscribing to an email newsletter service, or frequently visiting the IE section of microsofts web site. You may also consider a wider scope of protection in the form of evaluating, creation, or re-evaluating firewall a server(s). This is a must wether you are using an NT box, Linux Box, or some form of firewall software. Many times, firewall restrictionscan help restrict many downloads or transmissions that can bring trojan horses or viruses into your network. However, leaving a machine on, browser open or not, should always have Port 80 wide open.

Many times, with IE, it is the actual securitysettings under 'Internet Options' that can leave a computer vulnerable for attack by giving any dangerous scripting (ActiveX, Java, VB, etc.) the potential of the 'Go Ahead' to execute it upon that PC.

I hope that I have not bored you with all this senseless babble, and you get some understanding of it. Good Luck!

Paul

by intruzion

If the computers on your network are workstations then port 80 would not be open. When you leave your browser open then your computer is connected to another computer via port 80. This does not mean that port 80 is FULLY open. Port 80 is open to thewebsite you are currently connected to and not available to others. So the only possible security issue is if you trust the site you are connected to. If you don't you should configure your Internet Security settings to high.

Another scenario isthat the computers on your network are servers. In this situation, port 80 is ALWAYS open. It doesn't sound like this is the case but if you are serving a website than you should follow the appropriate steps at link below:

http://www.microsoft.com/technet/treeview/default.asp?url=/technet/security/tools/content.asp

Especially take a look at the hfnetchk tool which checks your system for the latest security patches.

For you bandwidth question, viewing a static webpage takes up no bandwidth once the page is downloaded to your computer. Dynamic webpages that generate anything that updates continuously is the only case of using up any bandwidth but this is such a small amount that it shouldn't even be considered an issue.

For best security, run a firewall that asks you before allowing anything to access the internet and also blocks all unwarranted attempts to scan or enter ports on your computers. You can configure a firewall to prompt you everytime these things occur but this is rather annoying. I use Norton Personal Firewall but ZoneAlarm is an excellent free firewall that can be easily downloaded and configured in seconds. ZoneAlarm can be downloaded at the following link:
http://www.zonealarm.com

Nasseam
nasseam@hotmail.com

by scott

It also depends on your ISP connection. An ISDN or DSL Router will supply some protection and also have an idle timer that can be programmed to disconnect and re-dial as needed. Many will also allow you to filter IPs and/or Ports to restrict trafficin either/both direction(s).

Scott@Gullys.com

by ralph

Your two-part answer is very simple:

Assumptions:
1. You have a session-state-aware firewall, such as a CheckPoint FW-1, Cisco PIX, etc.
2. You have port 80 allowed outbound for web browsing.
3. You are doing NAT for your internal network.
Answers:
1. If you have a browser that is "open", it depends on what it is doing.
(a) Sitting 'idle' on a web site that does not stream media - there is LITTLE potential issue. Your firewall will take care of this for you. It does not allow any packets inbound unless they match what your browser requested...so unless you have a trojan horse virus/worm (you're toast anyway) you're set.
(b) Sitting 'idle' on a site that streams media - then you have a bandwidth issue. Users are takingup bandwidth by listening to music, watching tickers, etc. Again, not much of a security concern there either.

The basics of the answer lie in the fact that your firewall, assuming it does session-state-awareness, will KNOW that a packet is coming from an outside address, to YOUR NAT'd inside address (10.xxx.xxx.xxx) because your computer requsted that packet. If you're running NAT, there is VERY little chance you are going to get 'by chance' exploited...trust me. Your users would ACTIVELY have to hit a site with virus-worm code on it...

Cheers!

This discussion is closed to new replies.