SIP Security 4

Question 1

What does 'media theft' or 'RTP hijacking' involve in a SIP attack scenario?

Accepted Answer

An attacker injects RTP packets to insert themselves into an audio stream

Answer

RTP hijacking involves an attacker sending spoofed RTP packets to replace or inject into a legitimate media stream, allowing them to hear or alter the conversation.

Question 2

Which RFC defines the SIPS URI scheme that mandates TLS for SIP communications?

Accepted Answer

RFC 3261

Answer

RFC 3261, which defines the core SIP protocol, also defines the SIPS URI scheme, requiring TLS transport for all hops in the signaling path.

Question 3

In SIP Identity (RFC 8224), what cryptographic format is used for the Identity header token?

Accepted Answer

JSON Web Token (JWT)

Answer

RFC 8224 SIP Identity tokens are JSON Web Tokens (JWTs) signed using the originating service provider's private key, allowing receivers to verify the signature.

Question 4

Which threat does the 'Record-Route' header manipulation pose in SIP security?

Accepted Answer

An attacker can insert themselves as a persistent on-path proxy for all in-dialog requests

Answer

By injecting a malicious URI into the Record-Route header, an attacker can ensure all subsequent in-dialog requests (like re-INVITEs and BYE) pass through their proxy.

Question 5

What is the role of a 'Back-to-Back User Agent' (B2BUA) from a security perspective?

Accepted Answer

It terminates and re-originates SIP calls, providing a security policy enforcement point

Answer

A B2BUA terminates and re-originates SIP sessions, allowing it to enforce security policies, strip sensitive headers, normalize content, and prevent malformed messages from propagating.

(SIP) Session Initiation Protocol Practice Test

(SIP) Session Initiation Protocol Practice Test

SIP Security 4