[VoiceOps] Preventing random SIP connections to handsets

[Alex Balashov]

On 11/20/2015 04:09 PM, Calvin Ellison wrote:

> challenge to BYE should mitigate that particular targeted attack.

Spoofed sequential (in-dialog) requests strike me as less of a concern
than initial requests, since, in order for the BYE to match an existing
dialog in the phone's UAS, the attacker would have to spoof a valid From
& To-tag, Call-ID, CSeq, etc.

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