[asterisk-biz] Fraud alert

[Alistair Cunningham]

Brent Vrieze wrote:
> Now a question.  Do we need to worry about our RTP ports we have open?

You don't need to fear fraudsters using open RTP ports to place 
unauthorised calls as this is purely handled at the SIP signalling 
level, but there are a few other concerns:

1. If they can sniff packets for your valid calls, they can spoof the 
source IP address, port, and sequence number of RTP packets to modify 
the audio your or your interlocutor hear. This is very hard to do and 
unless you're working in a highly sensitive industry this is not really 
a concern.

2. If a security bug is ever found in Asterisk's RTP code (and I've no 
specific reason to think it ever will), hackers could use this break 
into your machine at the OS level. As always, the best defence is to 
keep up to date with security alerts and apply updates any promptly. 
Firewalling RTP can also be a "belt and braces" approach.

Alistair Cunningham
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