[asterisk-users] getting invites to rtp ports ??

Thu Aug 30 04:51:56 CDT 2018

Hello Hans, 
maybe I don't rember SIP & Asterisk well, but I THINK it's absolutely possible to place a call from one Asterisk Server to another one without at SIP Provider in between.
Imagine a (big) company with branches running a server at every site.
But maybe I'm wrong....
But for other setups you're right. For example, on my asterisk machine firewall is closed except the (few) IP adresses my SIP provider told me
Norbert
-------- Ursprüngliche Nachricht --------Von: asterisk at a-domani.nl Datum: 30.08.18  12:04  (GMT+02:00) An: Asterisk Users Mailing List - Non-Commercial Discussion <asterisk-users at lists.digium.com> Betreff: Re: [asterisk-users] getting invites to rtp ports ?? 
Regarding this thread,
I was wondering, why would anybody opens his firewall (for incoming 
traffic), for anybody else, besides his own SIP-provider?

Isn't that the proper way for having your firewall configured: always, 
by default closed, unless explicitly required.
(but perhaps I'm missing a legitimate use-case)

Hans

On 2018-08-30 04:52, Matthew Jordan wrote:
> On Wed, Aug 29, 2018 at 6:20 PM Telium Support Group
> <support at telium.ca> wrote:
> 
>> Depending on log trolling (Asterisk security log) misses a lot, and
>> also depends on the SIP/PJSIP folks to not change message structure
>> (which has already happened numerous time).  If  you are comfortable
>> hacking chan_sip.c you may prefer to get the same messages from the
>> AMI.  It still misses a lot but that approach is better than
>> nothing.
>> 
>> Digium warns not to use fail2ban / log trolling as a security
>> system: http://forums.asterisk.org/viewtopic.php?p=159984
> 
> That's some pretty old advice.
> 
> The rationale for *not* using general log messages with fail2ban still
> stands: the general WARNING/NOTICE/etc. log messages are subject to
> change between versions, and no one wants that to impact someone's
> security. So you should not use those messages as input into fail2ban.
> 
> That rationale did lead to the 'security' event type in log messages.
> Security Event Logging - as it is called - got added into Asterisk
> quite some time ago. So long ago I'm really not sure which version. At
> a minimum, Asterisk 11, but I'm pretty sure it was in 10 as well.
> 
> Documentation for it can be found here:
> 
> https://wiki.asterisk.org/wiki/display/AST/Asterisk+Security+Event+Logger
> 
> And here:
> 
> https://wiki.asterisk.org/wiki/display/AST/Logging+Configuration
> 
> Note that this also fires off AMI events (and ARI events, IIRC).
> 
> If, for whatever reason, you do not get a SECURITY log message or a
> corresponding event when something 'bad' happens, that would be worth
> some additional discussion. If anything, the events can be a bit
> chatty...
> 
>> -----Original Message-----
>> From: asterisk-users
>> [mailto:asterisk-users-bounces at lists.digium.com] On Behalf Of sean
>> darcy
>> Sent: Wednesday, August 29, 2018 6:33 PM
>> To: asterisk-users at lists.digium.com
>> Subject: Re: [asterisk-users] getting invites to rtp ports ??
>> 
>> On 08/29/2018 11:59 AM, Telium Support Group wrote:
>>> Block a single IP is the wrong approach (whack-a-mole).  You
>> should consider a more comprehensive approach to securing your VoIP
>> environment.  Have a look at this wiki:
>>> 
>>> https://www.voip-info.org/asterisk-security/
>>> 
>>> 
>>> 
>>> -----Original Message-----
>>> From: asterisk-users
>> [mailto:asterisk-users-bounces at lists.digium.com]
>>> On Behalf Of sean darcy
>>> Sent: Wednesday, August 29, 2018 10:46 AM
>>> To: asterisk-users at lists.digium.com
>>> Subject: Re: [asterisk-users] getting invites to rtp ports ??
>>> 
>>> On 08/29/2018 09:42 AM, Carlos Rojas wrote:
>>>> Hi
>>>> 
>>>> Probably somebody is trying to hack your system, you should block
>> 
>>>> that ip on your firewall.
>>>> 
>>>> Regards
>>>> 
>>>> On Wed, Aug 29, 2018 at 9:34 AM, sean darcy <seandarcy2 at gmail.com
>> 
>>>> <mailto:seandarcy2 at gmail.com>> wrote:
>>>> 
>>>> I'm getting invites to very high ports every 30 seconds from
>> a
>>>> particular ip address:
>>>> 
>>>> Retransmitting #10 (NAT) to 5.199.133.128:52734 [1]
>>>> <http://5.199.133.128:52734>:
>>>> SIP/2.0 401 Unauthorized
>>>> Via: SIP/2.0/UDP
>>>> 
>> 
> 0.0.0.0:52734;branch=z9hG4bK1207255353;received=5.199.133.128;rport=52734
>>>> From: <sip:37120116780191250 at 67.80.191.250
>>>> 
>> <mailto:sip%3A37120116780191250 at 67.80.191.250>>;tag=1872048972
>>>> To: <sip:3712011972592181418 at 67.80.191.250
>>>> 
>> <mailto:sip%3A3712011972592181418 at 67.80.191.250>>;tag=as3a52e748
>>>> Call-ID: 1504207870-295758084-609228182
>>>> CSeq: 1 INVITE
>>>> .......
>>>> WARNING[150318]: chan_sip.c:4127 retrans_pkt: Timeout on
>>>> 1504207870-295758084-609228182...
>>>> 
>>>> I thought invites had to go to port 5060 or so. I don't
>> understand
>>>> why somebody (let's assume a bad guy) is trying ports above
>> 50000.
>>>> 
>>>> sean
>>>> 
>>>> 
>>> 
>>> Ok, so the high port is not the destination port but the source
>> port.
>>> 
>>> So I hacked the log warning in chan_sip.c on non-critical invites
>> to show the source ip:
>>> 
>>> ast_log(LOG_WARNING, "Timeout on %s non-critic invite trans from
>>> %s.\n",
>>> 
>> 
> pkt->owner->callid,ast_sockaddr_stringify(sip_real_dst(pkt->owner)));
>>> 
>>> With that in the log, I'm now blocking the ip addresses.
>>> 
>>> Thanks,
>>> sean
>>> 
>>> 
>>> --
>>> 
>> 
> _____________________________________________________________________
>>> -- Bandwidth and Colocation Provided by http://www.api-digital.com
>> --
>>> 
>>> Astricon is coming up October 9-11!  Signup is available at:
>>> https://www.asterisk.org/community/astricon-user-conference
>>> 
>>> Check out the new Asterisk community forum at:
>>> https://community.asterisk.org/
>>> 
>> 
>> I agree. That's why I hacked chan_sip.c to get the addresses in the
>> log.
>> 
>> I'm surprised they're not in the log by default. I must be the only
>> person who gets these "non-critical invites".
>> 
>> sean
>> 
>> --
>> 
> _____________________________________________________________________
>> -- Bandwidth and Colocation Provided by http://www.api-digital.com
>> --
>> 
>> Astricon is coming up October 9-11!  Signup is available at:
>> https://www.asterisk.org/community/astricon-user-conference
>> 
>> Check out the new Asterisk community forum at:
>> https://community.asterisk.org/
>> 
>> New to Asterisk? Start here:
>> https://wiki.asterisk.org/wiki/display/AST/Getting+Started
>> 
>> asterisk-users mailing list
>> To UNSUBSCRIBE or update options visit:
>> http://lists.digium.com/mailman/listinfo/asterisk-users
>> 
>> --
>> 
> _____________________________________________________________________
>> -- Bandwidth and Colocation Provided by http://www.api-digital.com
>> --
>> 
>> Astricon is coming up October 9-11!  Signup is available at:
>> https://www.asterisk.org/community/astricon-user-conference
>> 
>> Check out the new Asterisk community forum at:
>> https://community.asterisk.org/
>> 
>> New to Asterisk? Start here:
>> https://wiki.asterisk.org/wiki/display/AST/Getting+Started
>> 
>> asterisk-users mailing list
>> To UNSUBSCRIBE or update options visit:
>> http://lists.digium.com/mailman/listinfo/asterisk-users
> 
> --
> Matthew Jordan
> Digium, Inc. | CTO
> 445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
> Check us out at: http://digium.com & http://asterisk.org
> 
> Links:
> ------
> [1] http://5.199.133.128:52734

-- 
_____________________________________________________________________
-- Bandwidth and Colocation Provided by http://www.api-digital.com --

Astricon is coming up October 9-11!  Signup is available at: https://www.asterisk.org/community/astricon-user-conference

Check out the new Asterisk community forum at: https://community.asterisk.org/

New to Asterisk? Start here:
      https://wiki.asterisk.org/wiki/display/AST/Getting+Started

asterisk-users mailing list
To UNSUBSCRIBE or update options visit:
   http://lists.digium.com/mailman/listinfo/asterisk-users
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.digium.com/pipermail/asterisk-users/attachments/20180830/ce6ffa12/attachment-0001.html>