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Re: [Wlug] SSH problems

by Alex Camilo

that sounds interesting. although it might not work too well at WPI. i think the bester box would go nuts next time it randomly scanned my computer for vulnerabilities. On Fri, Oct 3, 2008 at 3:22 AM, Jeff Kinz <jkinz(a)kinz.org> wrote: > Eric - one way to stop the attacks is to let them in.... > > Time for a honeypot! IIRC a very simple C program can keep these > guys occupied for hours.. > > Suggestion - move your ssh access port, and run THP > > Tiny Honeypot > Quote: > > Wouldn't it be nice if every single unsolicited connection > attempt tied up the attacker who launched it by appearing to > actually work, all the while providing a little insight into > their motives and intents? thp appears to listen on all ports > otherwise not in legitimate use, providing a series of phony > responses to attacker commands. Some are very simple, others are > somewhat more interactive. The goal isn't to fool a skilled, > determined attacker...merely to cloud the playing field with tens > of thousands of fake services, all without causing unreasonable > stress on the thp host. > > > * Changelog: > http://www.alpinista.org/files/thp/thp-0.4.4/CHANGELOG > * Download: > http://www.l0t3k.net/tools/Honeypot/thp-0.4.6.tar.gz > * Home: http://www.alpinista.org/ > * License: GNU General Public License > * MD5SUM: 227ef8a3cedb49a1c634298f71a5832b > * Platform(s): Linux > > > > > > -- > _______________________________________________ > Wlug mailing list > Wlug(a)mail.wlug.org > http://mail.wlug.org/mailman/listinfo/wlug >

Oct. 3, 2008

Re: [Wlug] SSH problems

by Jeff Kinz

Eric - one way to stop the attacks is to let them in.... Time for a honeypot! IIRC a very simple C program can keep these guys occupied for hours.. Suggestion - move your ssh access port, and run THP Tiny Honeypot Quote: Wouldn't it be nice if every single unsolicited connection attempt tied up the attacker who launched it by appearing to actually work, all the while providing a little insight into their motives and intents? thp appears to listen on all ports otherwise not in legitimate use, providing a series of phony responses to attacker commands. Some are very simple, others are somewhat more interactive. The goal isn't to fool a skilled, determined attacker...merely to cloud the playing field with tens of thousands of fake services, all without causing unreasonable stress on the thp host. * Changelog: http://www.alpinista.org/files/thp/thp-0.4.4/CHANGELOG * Download: http://www.l0t3k.net/tools/Honeypot/thp-0.4.6.tar.gz * Home: http://www.alpinista.org/ * License: GNU General Public License * MD5SUM: 227ef8a3cedb49a1c634298f71a5832b * Platform(s): Linux --

Oct. 3, 2008

Re: [Wlug] SSH problems

by Eric Martin

John Stoffel wrote: > Eric> I have an outward facing ssh box at work that is currently being > Eric> attacked. somebody's going through a dictionary attack of > Eric> usernames; currently he or she is on abl. I can't block the IP > Eric> Address because the ip is different with each username. Does > Eric> anybody have any good ideas on how to stop this? I'm probably > Eric> going to move the ssh port to some random high number to get rid > Eric> of this, but I don't know yet if anybody else ssh's in besides > Eric> me. > > I've been running 'denyhosts' python script on both debian and FreeBSD > boxes I own. I don't like moving the SSH port because that's really > just security through obscurity. I'm not looking for extra security, I'm looking for clearing my logs and keeping the script kiddies away. I'm using real security, but it's nice to be able to read through your logs... > > And if your users have good passwords, it's unlikely that a dictionary > attack is going to work as well. Turned off password / pam / challengeresponse, just using PKI > > denyhosts works well, blocks hosts making multiple attempts, etc. > It's hard to block attacks where they do one attempt/per IP, but > hopefully it's going to take them long enough to run a useful sweep > that the won't get in. > > Fail2ban looks to be another good option as well, though I haven't > touched it. > > John I also want to look into fail2ban but I haven't had a chance yet. -- Eric Martin Key fingerprint = D1C4 086E DBB5 C18E 6FDA B215 6A25 7174 A941 3B9F

Oct. 2, 2008

Re: [Wlug] SSH problems

by John Stoffel

Eric> I have an outward facing ssh box at work that is currently being Eric> attacked. somebody's going through a dictionary attack of Eric> usernames; currently he or she is on abl. I can't block the IP Eric> Address because the ip is different with each username. Does Eric> anybody have any good ideas on how to stop this? I'm probably Eric> going to move the ssh port to some random high number to get rid Eric> of this, but I don't know yet if anybody else ssh's in besides Eric> me. I've been running 'denyhosts' python script on both debian and FreeBSD boxes I own. I don't like moving the SSH port because that's really just security through obscurity. And if your users have good passwords, it's unlikely that a dictionary attack is going to work as well. denyhosts works well, blocks hosts making multiple attempts, etc. It's hard to block attacks where they do one attempt/per IP, but hopefully it's going to take them long enough to run a useful sweep that the won't get in. Fail2ban looks to be another good option as well, though I haven't touched it. John

Oct. 1, 2008

Re: [Wlug] SSH problems

by Aaron Haviland

William Smith wrote, on Sep 30, 2008 at 21:47 EDT: > This might be of interest: http://www.fail2ban.org/wiki/index.php/Main_Page > > Basically, it detects hack attempts and locks off the offending IP > address for about five minutes by modifying firewall rules. > > I've only started looking at it myself, but I know others that use it > and it seems to work well. I've actually been using fail2ban for several years now one a few servers, with great success. .. except in the scenerio where it's unique IPs. I've actually been seeing a small amount of that today, as well, on one of my boxen, and as far as I can see, there's very little to no duplication of IPs, so fail2ban would not help at all in this case. fail2ban works for ssh attempts, where one IP fails login, for example, 3 times within 600 seconds, and also has rules for other daemons like bind, apache, exim, &c. Over the past month, it's been quiet the last couple weeks, but the beginning of September was *very* busy, and fail2ban saved me several headaches. -- Aaron Haviland 34 Wayne Ave, Dudley, MA home: [508] 943 - 7974

Oct. 1, 2008

Re: [Wlug] SSH problems

by William Smith

This might be of interest: http://www.fail2ban.org/wiki/index.php/Main_Page Basically, it detects hack attempts and locks off the offending IP address for about five minutes by modifying firewall rules. I've only started looking at it myself, but I know others that use it and it seems to work well. Bill Smith Fall River, MA Charter Member of LOPSA On Tue, Sep 30, 2008 at 8:03 PM, Alex Camilo <alex.camilo(a)gmail.com> wrote: > assuming the set of attacker IPs is finite. could you keep a running log of > IPs discard duplicates and add it to a block list for the duration of > the attack? > > On Tue, Sep 30, 2008 at 4:07 PM, Chuck Anderson <cra(a)wpi.edu> wrote: >> >> On Tue, Sep 30, 2008 at 03:54:52PM -0400, Alex Camilo wrote: >> > <clueless_newbie>just out of curiosity. >> > Could this be an attack from some sort of botnet? would that explain the >> > different IPs? >> >> Yes >> >> > or is he forging packets? >> > </clueless_newbie> >> >> Unlikely >> _______________________________________________ >> Wlug mailing list >> Wlug(a)mail.wlug.org >> http://mail.wlug.org/mailman/listinfo/wlug > > > _______________________________________________ > Wlug mailing list > Wlug(a)mail.wlug.org > http://mail.wlug.org/mailman/listinfo/wlug > >

Oct. 1, 2008

Re: [Wlug] SSH problems

by Eric Martin

Alex Camilo wrote: > assuming the set of attacker IPs is finite. could you keep a running log > of IPs discard duplicates and add it to a block list for the duration of > the attack? > > On Tue, Sep 30, 2008 at 4:07 PM, Chuck Anderson <cra(a)wpi.edu > <mailto:cra@wpi.edu>> wrote: > > On Tue, Sep 30, 2008 at 03:54:52PM -0400, Alex Camilo wrote: > > <clueless_newbie>just out of curiosity. > > Could this be an attack from some sort of botnet? would that > explain the > > different IPs? > > Yes > > > or is he forging packets? > > </clueless_newbie> > > Unlikely > _______________________________________________ > Wlug mailing list > Wlug(a)mail.wlug.org <mailto:Wlug@mail.wlug.org> > http://mail.wlug.org/mailman/listinfo/wlug > > > > ------------------------------------------------------------------------ > > _______________________________________________ > Wlug mailing list > Wlug(a)mail.wlug.org > http://mail.wlug.org/mailman/listinfo/wlug I forgot to mention that the box is also a webserver that clients log into, so blocking IPs (other than ssh) may keep people from accessing a website...It's moving slowly also, (s)he is on ajs right now, as opposed to ach when I sent the original email... -- Eric Martin Key fingerprint = D1C4 086E DBB5 C18E 6FDA B215 6A25 7174 A941 3B9F

Oct. 1, 2008

Re: [Wlug] SSH problems

by Alex Camilo

assuming the set of attacker IPs is finite. could you keep a running log of IPs discard duplicates and add it to a block list for the duration of the attack? On Tue, Sep 30, 2008 at 4:07 PM, Chuck Anderson <cra(a)wpi.edu> wrote: > On Tue, Sep 30, 2008 at 03:54:52PM -0400, Alex Camilo wrote: > > <clueless_newbie>just out of curiosity. > > Could this be an attack from some sort of botnet? would that explain the > > different IPs? > > Yes > > > or is he forging packets? > > </clueless_newbie> > > Unlikely > _______________________________________________ > Wlug mailing list > Wlug(a)mail.wlug.org > http://mail.wlug.org/mailman/listinfo/wlug >

Oct. 1, 2008

Re: [Wlug] SSH problems

by Eric Martin

Chuck Anderson wrote: > On Tue, Sep 30, 2008 at 03:54:52PM -0400, Alex Camilo wrote: >> <clueless_newbie>just out of curiosity. >> Could this be an attack from some sort of botnet? would that explain the >> different IPs? > > Yes > >> or is he forging packets? >> </clueless_newbie> > > Unlikely > _______________________________________________ > Wlug mailing list > Wlug(a)mail.wlug.org > http://mail.wlug.org/mailman/listinfo/wlug agreed -- Eric Martin Key fingerprint = D1C4 086E DBB5 C18E 6FDA B215 6A25 7174 A941 3B9F

Sept. 30, 2008

Re: [Wlug] SSH problems

by Tim Keller

It most definitly is. If you expose a box with default ports for any amount of time you'll see all sorts of fun stuff taking a wack at it. If you need to connect from random places, and you can keep your keys safe, going key only and then moving the port is probably going to keep you pretty safe. On 9/30/08, Alex Camilo <alex.camilo(a)gmail.com> wrote: > <clueless_newbie>just out of curiosity. > Could this be an attack from some sort of botnet? would that explain the > different IPs? > or is he forging packets? > </clueless_newbie> > > On Tue, Sep 30, 2008 at 1:43 PM, Eric Martin <freak4uxxx(a)gmail.com> wrote: > >> I have an outward facing ssh box at work that is currently being >> attacked. somebody's going through a dictionary attack of usernames; >> currently he or she is on abl. I can't block the IP Address because the >> ip is different with each username. Does anybody have any good ideas on >> how to stop this? I'm probably going to move the ssh port to some >> random high number to get rid of this, but I don't know yet if anybody >> else ssh's in besides me. >> >> Thanks in advance >> -- >> Eric Martin >> Key fingerprint = D1C4 086E DBB5 C18E 6FDA B215 6A25 7174 A941 3B9F >> >> >> _______________________________________________ >> Wlug mailing list >> Wlug(a)mail.wlug.org >> http://mail.wlug.org/mailman/listinfo/wlug >> >> > -- Sent from Gmail for mobile | mobile.google.com I am weary of the allegiances of any politician who refers to their constituents as "consumers".

Sept. 30, 2008