ACA Security & Authentication in VoIP

Question 1

Which transport protocol does TLS (Transport Layer Security) replace in SIP to provide encrypted signaling?

Accepted Answer

UDP and TCP (TLS runs over TCP providing encryption)

Answer

TLS runs over TCP and provides encryption, authentication, and integrity for SIP signaling, replacing unencrypted TCP (and effectively UDP where TLS/TCP is used instead).

Question 2

In AudioCodes Mediant TLS configuration, what is the role of the 'TLS Context'?

Accepted Answer

It groups TLS certificates, keys, and cipher suites applied to SIP interfaces or SBC legs

Answer

A TLS Context bundles the certificate chain, private key, trusted CA certificates, and cipher suite preferences applied to one or more SIP interfaces for mutual TLS.

Question 3

What attack does 'SIP Digest Authentication' (using 401/407 challenges) protect against in VoIP environments?

Accepted Answer

Unauthorized call origination by requiring valid credentials before processing INVITE or REGISTER requests

Answer

SIP Digest Authentication uses a challenge-response mechanism (MD5/SHA hash of credentials) to verify that the calling entity is authorized before allowing call setup or registration.

Question 4

Which AudioCodes SBC security feature rate-limits SIP messages to protect against DoS and flooding attacks?

Accepted Answer

SIP Message Policy (SIP Whitelist/Blacklist and rate limiting)

Answer

AudioCodes SBC includes SIP message classification and rate-limiting policies that block or throttle excessive SIP messages from unknown or suspicious sources, mitigating DoS attacks.

Question 5

What is 'SPIT' (Spam over Internet Telephony) and which AudioCodes feature helps mitigate it?

Accepted Answer

Unsolicited bulk VoIP calls; mitigated via SIP blacklists, CAPTCHA challenges, and call rate limiting

Answer

SPIT refers to automated spam calls over VoIP; AudioCodes SBC counters it using SIP source blacklisting, registration rate limiting, and anomaly detection policies.

ACA - Audiocodes Certified Associate Practice Test

ACA - Audiocodes Certified Associate Practice Test

ACA Security & Authentication in VoIP