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Voice Call DoS

The Voice Call DoS sensor looks for a single phone that calls repeatedly over a short time. This type of attack differs from other Denial of Service (DoS) attacks because of its low volume. It only takes about 10 calls per minute to keep a phone ringing all the time. A traditional intrusion detection system may not catch the attack.

Troubleshooting a VoIP DoS Attack Alert

The anomaly event identifies the IP address of the phone that is called. Check to see who is calling the phone. Use the UCM dashboard to determine which calls were made during the attack time frame.