how do i set up dual boot again, possible virus caused problems...

[justchillin]

ok well last night "something" caused by computer to "flip out"...i noticed that it seemed to be in dos but there was allot of info displaying on the screen real fast and after turning it off i was told there was no hard disk detected...
so after talking to tech support i got windows up and everything seems to be normal. except the boot screen i use to get to boot linux doesn't come up.

how do i get back into linux??

also can you recomend any fod anti virus software for linux???

[solo]

Depending on the distibution of Linux you have, you may be able to boot from the CD (the same one you installed from). If you can use this method to get back into Linux, then all you need to do is reconfigure LILO (or whatever bootloader you were using).

If you suspect a virus, it most likely came in through Windows instead, but the first thing you should do (after booting into Linux) is check your logs. If you see anything unusual in there, then you may have been hacked.

Two preventative measures to take are:

1) Make a boot disk for Linux, and keep it current if your bootloader is altered at all.

2) Make sure you are aware of the security risk with Linux (especially when surfing the internet in Linux). At the very least; shut down any services in inetd that you aren't using.

[justchillin]

first, thanks for the reply i'm running mandrake 8.0 if that helps...

second, how do i check my logs and what should i be looking for??

third, what firewalls would you recomend??? the only one i've heard of is firestarter but i wasn't sure if it was any good or exactly how hard it was to setup...

as you can tell i'm very new at this so any help you can give is appreciated...

thanks.

[solo]

Your logs are in the /var directory. There is a good NHF about Linux security (mentioning log maintainance/monitoring) right here at LNO. If you see anything drastic like empty log files, or extremely large log files, this is suspect. Also, check your existing user list. If there are account(s) there that you know you didn't create (other than the Linux default accounts), this is also suspect.

I haven't actually setup a firewall in Linux yet; mostly because I'm a spineless coward that is affraid to deal with complicated networking/internet issues (same reason I haven't actually rebuilt a kernel, or compiled an application yet either :rolleyes: ). I've read that Bastille Linux (an application, not a distro) is good, and helps teach you about networking security issues:


http://www.bastille-linux.org/

I plan to try it soon (after I grow a spine, that is :D ). Hope that helps.

[justchillin]

thanks for the help...

i think i need to go buy a book and lock myself in my apartment for a week and do nothing but play around and see what happens...

thanks again i'll check out my logs when i get home...

oh, if i did get hacked (which i probly did) and i'm not logged into linux can the hacker still gain access???