SIP Security 2

Question 1

Which SIP header field is used to carry authentication credentials from a client to a server?

Accepted Answer

Authorization

Answer

WWW-Authenticate

Answer

Proxy-Authenticate

Answer

Security-Client

Question 2

What does the 'nonce' parameter in SIP Digest Authentication prevent?

Accepted Answer

Replay attacks

Answer

Man-in-the-middle attacks

Answer

DNS spoofing

Answer

TLS downgrade attacks

Question 3

Which protocol provides end-to-end encryption of SIP message bodies but NOT the SIP headers?

Accepted Answer

S/MIME

Answer

TLS

Answer

IPsec

Answer

SRTP

Question 4

A SIP 'registration hijacking' attack occurs when an attacker:

Accepted Answer

Registers a fake binding for a legitimate user's AOR

Answer

Intercepts SIP INVITE messages in transit

Answer

Floods a SIP server with REGISTER requests

Answer

Modifies the SDP body to redirect media

Question 5

Which SIP security mechanism uses the 'Identity' header to provide cryptographic proof of caller identity?

Accepted Answer

RFC 8224 (STIR)

Answer

Digest Authentication

Answer

TLS mutual authentication

Answer

S/MIME signing

Question 6

What is the purpose of the 'qop' (quality of protection) parameter in SIP Digest Authentication?

Accepted Answer

It specifies whether authentication, integrity, or both protections are applied

Answer

It sets the encryption algorithm for the SIP session

Answer

It determines the length of the nonce value

Answer

It defines the maximum number of authentication retries

Question 7

Which attack targets SIP infrastructure by sending a high volume of crafted SIP messages to exhaust server resources?

Accepted Answer

SIP flooding (DoS)

Answer

Toll fraud

Answer

Eavesdropping

Answer

SPIT (Spam over Internet Telephony)