Smart. I would just point out if someone didn't catch it in my last post. When one of my servers was compromised (a demo machine that had weak passwords that was left running), the sniffing was done days prior and right at 5pm EST on a Friday is when it started doing it's dirty work. It just so happen that I had follow-me service setup on the incoming line, thus got the flood of complaints almost instantly. Otherwise, it would have worked all weekend until Monday sometime if I was lucky enough to check my CDR records. Could have been a pretty penny if they utilized all the channels / capacity they had their hands on.
Regards, Chuck -----Original Message----- From: Stephan Monette [mailto:[EMAIL PROTECTED] Sent: Tuesday, November 11, 2008 7:16 PM To: asterisk@uc.org Subject: Re: [on-asterisk] SIP hack attempts Hey everyone, Another trend we see in this hacking activity: The hackers seems to be collecting SIP accounts hacked for a few weeks from one server and then from a different IP address/Asterisk server they start using the hacked accounts earlier to make their fraudulent calls. There could be weeks between the time they discover your weak SIP account and the time they start using it. Did you know that if someone gets hurt and that same person can prove the calls are being made by your phone system, the administrator of your phone system can be sued for being negligent to properly secure their systems and are personally responsible for any damages cause by this action! Very scary! Another easy way to reduce your system from being hacked is to design a mouse trap: create an extension 200 with password 1234. Then you program a separate context for extension 200 with no possibilities to make any calls. Most hackers stop sniffing for passwords after successfully guessing the first account. Then design a small tool to gather IP addresses that uses extension 200 and block all access from those IP addresses. Cheers. Stephan Monette Unlimitel Inc. Tel.: 613-688-6212. x221 TF : 1-877-464-6638, x221 FAX : 613-482-1077 Chuck Mariotti wrote: > I also made some recommendations to Unlimitel, but maybe this should be > shared with providers as to what would have allowed me to catch this issue: > > I know this is likely a lot of work, but... it would be nice to have the > daily totals in the body of the email and subject. I rarely open my email > attachment to see the minutes used for a day, but if there was a dollar > amount or # of minutes in the subject, it would make it easier to scan with > the eyeball. I would have missed our recent hack completely if I didn't get > returned calls complaining... which made me check my CDR in Asterisk, which > made me look the next day in your report. It also happened on a Friday night > (I'm sure on purpose) so I wouldn't have even attempted to look until Monday. > > I know that's a lot more horsepower needed than just attaching a text file. > But I know it would be helpful to me. > > As well, could be useful to set an alert on DID for minutes used in a day... > I think that's asking too much though. > > Regards, > > Chuck > > -----Original Message----- > From: Chuck Mariotti [mailto:[EMAIL PROTECTED] > Sent: Tuesday, November 11, 2008 6:40 PM > To: Simon P. Ditner; asterisk@uc.org > Subject: RE: [on-asterisk] SIP hack attempts > > Simon, I ran into and was a victim of such an attack back in mid-august. I > emailed unlimitel and this is the recommendations that Stephen had: > > > Dear Customer, > We're seeing a lot more hacking activities lately and here's a short list to > do on your server to help keep it secure: > 1- Change all your default passwords on the server (root, admin, maint). > Never use easy to remember passwords like 1234,... > 2- Never use passwords like 1234 for your any extensions on your server. > There's a lot of hackers out there just scanning your Asterisk server to > detect extensions (200 to 299 mostly) with easy passwords like 1234. > 3- Block access to your server and just leave the RTP, SIP and IAX2 opened. > Just leave the SSH and WEB access opened to your static IP from the office. > You can do this by using the iptables from Linux on your Asterisk server. > 4- Monitor your network and if you see some activities scanning your server, > keep note of the source IP address and block it completely from your server. > Hope this few tips can help you keep your server more secure and avoid big > telephone bills. > Stephan Monette > Unlimitel Inc. > > > -----Original Message----- > From: Simon P. Ditner [mailto:[EMAIL PROTECTED] > Sent: Tuesday, November 11, 2008 6:00 PM > To: asterisk@uc.org > Subject: Re: [on-asterisk] SIP hack attempts > > Not a single reply? > > It's very easy to disregard this message, but I think this is something > VERY IMPORTANT that we should be talking about much more -- especially > for those deploying systems for remote workers over a public network. > There is a huge opportunity for toll fraud, voip spam, and such as this > market segment continues to grow. > > Lability becomes an issue too -- who's responsible when someone is > defrauded via your phone system? The phone companies have a record of you > calling so-and-so; can you prove you didn't? > > These are the sort of scans I've been spotting hitting some of my systems > the past week, trying to brute force. You'll see incremental scans like: > > [Nov 5 19:58:30] NOTICE[19408] chan_sip.c: Registration from '"0"<sip:[EMAIL > PROTECTED]>' failed for 'EE.FF.GG.HH' - No matching peer found > ... > [Nov 5 20:20:21] NOTICE[19408] chan_sip.c: Registration from > '"1000"<sip:[EMAIL PROTECTED]>' failed for 'EE.FF.GG.HH' - Wrong password > ... > > We were discussing this around the office, particularly how sipvicious > (http://sipvicious.org) works, and it was noted that you can find active > SIP accounts easily, and then start a brute force against a known active > account. > > I poked my head into #asterisk-dev, and asked if there were a feature in > the works to automatically disable accounts after a number of bad auth > attempts. It's been discussed, but so far no code. > > There are however some easy things you can do that are common across > running any service on the internet. > > Inside of asterisk, you can cut down on your exposure by only allowing > particular SIP accounts to be registered from remotely by putting > deny-based ACL's on the other accounts, listing your local subnets as > permissable: > > sip.conf > [somepeer] > type=peer > deny=0.0.0.0/0.0.0.0 > permit=192.168.0.0/255.255.255.0 > > You can also create automatic blacklisting of IP addresses that attempt > too many SIP authentications per interval, such as this SSH example: > > http://www.mattiasholm.com/node/6 > > Thoughts? What are other people doing to protect their exposure? > > re, > spd > > On Mon, 10 Nov 2008, Andre Courchesne - Consultant wrote: > > >> Hi, >> >> Just to let you know that I see a proliferation is SIP hack attempts. Twice >> today I happened to be logged in servers where I saw SIP discovery from IP >> 212.12.148.109 and on the other server that same IP had actually gained >> controlled of a SIP account (which was created with a weak secret by the >> administrator). >> >> The call pattern indicated that calls were made by a dialer of some sort >> and the SIP packets were originating from an Asterisk server. >> >> So be carefull about your server that you have to let unprotected on an >> internet segment. >> >> Andre >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: [EMAIL PROTECTED] >> For additional commands, e-mail: [EMAIL PROTECTED] >> >> >> > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > > > > > --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
