Very sorry fif this post seems elementary, I don’t know much about computers…
A friend of mine has a hacker who has invaded their computer. They use cable access. Everytime they are on the internet, their searches are changed, documents are played with etc, etc.
How can they get rid of this invader?
Have him call his cable access provider and have them change his static IP address. Also install a good firewall, such as ZoneAlarm. Even the free version is excellent.
Get a firewall, download ZoneAlarm which is a free software firewall that is quite effective. It allows you to choose which program can access the internet and which ones you suspect are bogus. try download.com
Learn more about computers and hacking. Most hackers are just kids trying out a new way of getting into mishief. They have so many open computers that they’d pick the easy “mark” rather than try to challenge you. Make it hard for him and most will just give up and go away.
Turn off your computer when not in use (including the internet connection if you have a external cable modem or wireless router. They cant access your computer if its off.
Other than placing passwords, i think that should discourage your unwanted hacker.
Disconnect from the network, then reformat the hard drive and start from scratch.
It’s the only way to be sure. The cracker may have left any number of backdoors into their computer, and unless they really know what they’re doing, they’re probably not going to find them all.
When they get back up, they should make sure that file sharing, printer sharing and other things like that are turned off. Then they should go back online and immediately go and update to the latest version of their system software. ( http://windowsupdate.microsoft.com for a windows machine, Software Update in the controls panel on a Mac).
Then they should go get a firewall system like Zone Alarm ( http://www.zonelabs.com/ ) or Symantec’s Norton Personal Firewall ( http://www.symantec.com/sabu/nis/npf/ ). They should also get antivirus software as well, and make sure that the virus checker file is up to date.
They should then disconnect from the net again and scan everything on their hard drive with the virus checker.
ZoneAlarm pretty well isolates any backdoors, so I wouln’t go to such extreme lengths myself. But if you’re the paranoid type, it can’t hurt, anyway.
Is there such a thing as a HW firewall? I’ve heard it mentioned but never in much detail.
Yeah, there is. Most decent network hubs and routers include hardware firewalls as part of the firmware. In practice these are actually much more effective than software firewalls.
Zone alarm is a good piece of software because it will tell you what programs are trying to use the network. Most of the programs that need the internet are obvious one. Your browser, your email program and 1 or 2 operating system programs. If a weird program starts using the internet you are notified and can disallow the connection something an external firewall cannot do.
One of the main reasons a hardware firewall is better is that some backdoor trojans can disable a software firewall from the inside, but a hardware firewall is impervious to such attacks. See here and here for more information.
I’d go with buckgully’s advice because many of the programs hackers use on your computer to access the Internet have “official” sounding names. Your friends might allow one of these programs access to the Internet, especially on the first use of ZoneAlarm.
Visit grc.com and do the “Shield’s Up” test. Shield’s Up will test your DSL/Cable computer for hacker problems. This site was designed by the author of ZoneAlarm. This site gives detailed, step by step, instructions to follow buckgully’s advice.