SIP Security 3

Question 1

In SIP, what does 'SPIT' stand for and what threat does it represent?

Accepted Answer

Spam over Internet Telephony — unsolicited bulk voice calls

Answer

SPIT (Spam over Internet Telephony) refers to unsolicited bulk calls over VoIP, analogous to email spam but for voice communications.

Question 2

Which SIP header prevents a response from being replayed by an attacker to a different transaction?

Accepted Answer

CSeq

Answer

The CSeq (Command Sequence) header contains a monotonically increasing number that ties responses to specific requests, preventing response replay across transactions.

Question 3

What is a 'SIP proxy poisoning' attack?

Accepted Answer

Injecting false routing information to redirect SIP traffic through a malicious proxy

Answer

SIP proxy poisoning involves corrupting routing tables or DNS records so that SIP traffic is redirected through an attacker-controlled proxy.

Question 4

Which field in the SIP Digest Authentication challenge is used to prevent cross-realm credential reuse?

Accepted Answer

realm

Answer

The 'realm' parameter identifies the protection domain, ensuring that credentials generated for one realm cannot be reused in authentication challenges from a different realm.

Question 5

TLS in SIP provides security for traffic between which entities?

Accepted Answer

Adjacent SIP hops (hop-by-hop)

Answer

TLS in SIP provides hop-by-hop security, encrypting traffic only between directly connected SIP entities, not end-to-end.

(SIP) Session Initiation Protocol Practice Test

(SIP) Session Initiation Protocol Practice Test

SIP Security 3