[OpenSIPS-Users] Accounting: How to avoid a fraudulent BYE with lower CSeq?

Iñaki Baz Castillo ibc at aliax.net
Sat Dec 20 10:27:08 CET 2008


El Viernes, 19 de Diciembre de 2008, Bogdan-Andrei Iancu escribió:
> I guess you are refering to attacks like sending to proxy BYEs with RURI
> or Route info pointing somewhere else than the GW and the proxy will
> record end of call, but the GW does not actually receive a BYE.

Victor just means that a real customer could authenticate his spoofed BYE but 
this would be correctly handled with your suggestions in other mail:

--------------
You can control this via the "failed_transaction_flag" = 
http://www.opensips.org/html/docs/modules/1.4.x/acc.html#id2500684

If direction is from GW, set the flag and account BYE disregarding the 
reply code; If direction is from client, do not set and acount BYE only 
if reply is 200 OK
----------------

But what you mean now is really worse than what I was thinking about XD
For example, a legitime user in a legitime call with the gateway could send a 
spoofed BYE with RURI pointing to **himself** (and reply 200 to himself), so 
the proxy would account this call as terminated !!!

There is no way to prevent it!!!

-- 
Iñaki Baz Castillo



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