Techniques for protecting telephone users from caller ID spoofing attacks

A method to be performed by a telephony apparatus to protect telephone users from caller ID spoofing, the method comprising:

• receiving an incoming telephone call in the telephony apparatus, the telephone call being for a telephone user;
• checking a caller ID of the telephone call against a plurality of caller groups, each caller group in the plurality of caller groups comprising telephone numbers of related callers belonging to the telephone user's contact list and is associated with an audio message in a plurality of audio messages, each audio message in the plurality of audio messages including a question that callers from a corresponding caller group know the answer to based on the callers' relationship with the telephone user;
• playing a first audio message in the plurality of audio messages when the caller ID of the telephone call corresponds to a telephone number in a first caller group in the plurality of caller groups;
• receiving a first answer to a first question in the first audio message;
• and
• forwarding the telephone call to the telephone user when the first answer is correct.