Check out the following article. It states that over 200,000 voice phishing/vishing calls into Korea, from other countries, were blocked in January and February.
The Messaging, Malware and Mobile Anti-Abuse Working Group (M3AAWG) is holding a special interest group in their annual conference in San Francisco, February 17-21, to focus on issues unique to voice.
J. Oquendo has created the "VoIP Abuse Project" or "VoIP Blacklist Project"
I just finished a chapter in my upcoming book, Hacking Exposed: VoIP and UC on Social Engineering and Voice Phishing.
Here is a link to a recent presentation for an analysis of a massive scan of the entire IPV4 address range for SIP servers:
Here is an article from earlier in the year on VoIP phishing/vishing.
Here is a discussion of a recent voice phishing or vishing attack against hotel guests. It is really more of a social engineering attack, but thats ok. Apparently someone calls into hotels late at night, poses as a hotel employee, and tries to trick guests into disclosing personal information, including name, credit card info, etc.
It doesn't seem like a very effective attack - most guests would be furious that they were woken up.
Check out our webinar on threats to contact centers.
Below is a recent article talking about voice phishing, also known as vishing.
Here is an article in USA Today about a number of phone/voice phishing and other fraud scams.
Here is an article describing how caller ID spoofing is being used for voice phising (they call it vishing) attacks.