starting by iptable deny all of china is a good start. - Re: OT? Linux-based trojans now targeting WRT and other linux-based routers

[Andrew "Tuna" Harris]

Excerpts from Charles Jones's message of Mon Mar 30 08:46:35 -0700 2009:
> Andrew "Tuna" Harris wrote:
> > Excerpts from kitepilot at kitepilot.com's message of Mon Mar 30 05:30:51 -0700 2009:
> >   
> >> And how do I:
> >> "starting by iptable deny all of china" ? 
> >>
> >> I can figure out the "iptable" part, it is the "china" part (and other 
> >> possible places where I know I will only get spam from) that I am unaware 
> >> of... 
> >>
> >> Thanks!
> >> Enrique 
> >>
> >>     
> >
> > Easy! There are online lists of Chinese and Korean IP blocks that you
> > can deny. I found one that came with a perl script to do it all
> > automagically.
> >
> > http://is.gd/pEsB
> >
> > That guy has some other interesting things too. Nice blog he's got goin'
> > there.
> >
> > But I HIGHLY suggest you read those files to make sure there's nothing
> > you don't want blocked out. You can just comment out things you don't
> > want blocked in the access.list file. It's all plaintext.
> >
> > And definitely give ANYTHING you run as root a second look. This script
> > is okay for me but it's always good to be a little paranoid.
> >
> >   
> >> Lisa Kachold writes: 
> >>
> >>     
> >>> Well, the sad fact is that _any_ machine will kick over and barf it's guts under distributed attacks; it just depends on what it does after the green slime clears..
> >>> Also, it really helps if you run one that won't take WRT, or only runs on an arm, with small memory therefore they aren't too hot to pwn you.  Linksys put out the source, whereupon I built my own, and played with the features; you know kiddies are doing this also.   
> >>>
> >>> Course, if you have a WRT-able router, it's a good idea to set it up as a small linux system, but you have to know how to work it; starting by iptable deny all of china is a good start.
> >>> I have had mine owned regularly; I just flash it again.  Mine is easy to determine, since it suddenly starts showing AIM ports open.  Once they target you successfully, they will insidiously continue to keep track of you; rather like trophy hunting.
> >>> I could have done a complete defcon presentation on various routers by this time.  
> >>> That's why I always suggest to everyone, if you see something strange, you see something strange, report it, complain, study it, rather than continuing to agree with everyone in denial about the sad state of security.
> >>> Obnosis | (503)754-4452 
> >>>
> >>>  
> >>>
> >>>
> >>> PLUG Linux Security Labs 2nd Saturday Each Month at Noon - 3PM 
> >>>
> >>>  
> >>>
> >>>  
> >>>
> >>>
> >>>       
> >>>> Subject: Re: OT? Linux-based trojans now targeting WRT and other linux-based    routers
> >>>> From: tuna at supertunaman.com
> >>>> To: plug-discuss at lists.plug.phoenix.az.us
> >>>> Date: Fri, 27 Mar 2009 17:57:34 -0700 
> >>>>
> >>>> Excerpts from Charles Jones's message of Fri Mar 27 14:19:05 -0700 2009:
> >>>>         
> >>>>> http://www.linux-magazine.com/online/news/psyb0t_attacks_linux_routers_update
> >>>>>
> >>>>> Some parts of this article made me LOL. Like:
> >>>>>
> >>>>> "One type of malware connects primarily to a chat system such as IRC, 
> >>>>> which your ordinary 14-year-old might join for the latest superstar gossip."
> >>>>>
> >>>>> and:
> >>>>>
> >>>>> "Each IRC network usually has hundreds of these channels, typically 
> >>>>> starting with a hash mark in its name, such as #superstars."
> >>>>>
> >>>>> and:
> >>>>>
> >>>>> "A participant joining a channel who is not a human is usually a program 
> >>>>> called a bot. There are all kinds of bots lurking in the IRC, some of 
> >>>>> them explain UNIX commands, look up bus schedules or forecast the 
> >>>>> weather. Some, however, await special, often secret, commands"
> >>>>>
> >>>>> Which prompted me to say on IRC:
> >>>>> [03-27-2009 14:11:10] <Charles> hahaha
> >>>>> [03-27-2009 14:12:54] * Charles is awaiting special secret commands
> >>>>> [03-27-2009 14:13:28] <Charles> but only if you are a superstar
> >>>>>
> >>>>> Seriously though, I sadly have a lot of experience being attacked by, 
> >>>>> and hunting down and eradicating botnets. Infected routers are really 
> >>>>> evil, since your typical user has no way to notice or see that something 
> >>>>> is running that should not be. This could become a real problem as WRT 
> >>>>> and other linux-based routers become more popular. 
> >>>>>           
> >>>> I just wish I had come up with the idea of WRT-based botnets first. :< 
> >>>>
> >>>> I guess the vendors will just have to set randomly generated default
> >>>> passwords, and pass along a little card that says "omgwtfbbq ur password
> >>>> lol". But you KNOW that they'll never get around to that soon.
> >>>> ---------------------------------------------------
> >>>>         
> I only perused it quickly, but it looked to me like that guys script 
> blocks EVERYTHING except trusted IPs, not just china? It has an "INPUT 
> -p tcp --dport 22 -j DROP" at the end.  I don't understand why it goes 
> through the trouble to block china IP blocks, if its blocking 
> *everything* other than the trusted list anyway?
Right, so just comment out that bit and you're fine.

> "*The access.list file is pre-configured to drop packets from all of the 
> IP blocks* at http://www.okean.com/antispam/sinokorea.html.  However, 
> you should jump to the bottom of *access.list* and add any trusted IP's 
> (e.g., work and home) that you want to accept SSH traffic from.  _By 
> default, any other incoming requests on port 22 from addresses you don't 
> trust will be dropped_."
> 
> Please tell me if I am wrong, after all it is Monday morning and I may 
> not be thinking clearly :)