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

UDP only

Answer

SCTP

Answer

IPsec

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

It defines the UDP fallback timeout when TLS fails

Answer

It specifies the TLS version used for HTTPS management only

Answer

It manages the SRTP key exchange method

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

Eavesdropping on RTP media streams

Answer

BGP route hijacking of SIP trunks

Answer

DNS poisoning of SIP proxy records

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

SNMP ACL

Answer

Firewall Rule Sets

Answer

IP Group Bandwidth Limit

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

A type of RTP injection attack; mitigated with SRTP

Answer

A SIP header spoofing technique; mitigated with TLS

Answer

A codec negotiation exploit; mitigated with SDP filtering

Question 6

In AudioCodes Mediant, which feature detects and blocks SIP INVITE flood attacks in real time?

Accepted Answer

Intrusion Detection System (IDS) / SIP Robustness

Answer

QoS Policing

Answer

RTCP-based Anomaly Detection

Answer

SIP Session Border Policy