Some easy questions about security in linux on the net
 

Hello, Can you tell me about these 2 questions about linux?

As in windows can dealers or other malware get into my computer without my consent?

What about windows virus? Can they affect linux or it is needed to do special linux viruses?

Thanks a lot

Re: Some easy questions about security in linux on the net
 

As in windows can dealers or other malware get into my computer without my consent?
Yes, so don't fall in to the trap of thinking that because you are using llinux that you don't have to worry about security. Crackers, malware, rootkits have an impact on all operating systems.

What about windows virus? Can they affect linux or it is needed to do special linux viruses?
Windows-specific viruses cannot directly damage Linux systems, but they can indirectly have an effect through open file shares with other Windows systems. In that circumstance, you can have an infected windows box writing garbage to a a Linux share. The Linux system can also serve as a "carrier" of windows viruses, but in general you don't have to be concerned about windows viruses or worms. However there are Linux viruses, but they are exceedingly rare and require some degree of user stupidity to work (ie. executing a strange file as root). There are anti-virus programs for Linux (F-Prot, ClamAV, Kaspersky Lab) but to be honest, having anti-virus software is optional. It really depends on your level of paranioa and if you have extra money to spend. If you spend time securing your system and maintain good secure computing practices, then you really don't have to worry. Your time would be better spent hardening and patching. The Security References thread at the top of the forum is a really good place to start learning about those things.

The above post is quite correct. I was writing my response in the time the about response was submitted so I have repeated some things, but I believe it is still relevant.

These question can lead to a very heated discussion. In the most simple terms, yes, It is possible for an attacker to exploit, remotely, some vulnerability which could give that attacker root access to the system.

As for Windows viruses proper, in the form of email viruses, or viruses that exploit windows specific vulnerabilities then no. However some Widows viruses can produce a denial of service affect on Linux boxes. Most of these viruses better known as worms can create significant network traffic which could adversely affect a Linux host. For example I am aware of some cases where the <spelling> "welcha" </spelling> worm rendered some Linux firewall gateways unreachable over the network.

There is much more to this issue of security then described above or put forth in your question. As rule of thumb (speaking from a security stand point not a Linux advocacy stand point) the open nature of Linux and its Open source tools make it more secure. This can be argued of curse but there are many "independent" studies that show this to be the case.

Don't get me wrong windows is a very useful platform. Remember there is a right tool for every job, Linux just happens to be the tool of choice for me!

The correct/complete answer to your question is very long an quite complicated and is bound to have some holes. Hope fully this will spark some discussion here and you will get a more complete picture. But in the meantime I would do some more research.

There are already two threads where this was discussed pretty extensively. The one on "Linux most vulnerable?" and "Do viruses exists for Linux?" have pretty much the full range of arguments from both points of view.