Public Service Announcement

Prepared by the Internet Crime Complaint Center (IC3)

December 5, 2008 Updated on December 8, 2008
FBI Logo

New Technique Utilizing Private Branch Exchange (PBX) Systems To Conduct Vishing Attacks

The FBI has received information concerning a new technique used to conduct vishingi attacks. The recent attacks were conducted by hackers exploiting a security vulnerability in Asterisk software. Asterisk is free and widely used software developed to integrate PBXii systems with Voice over Internet Protocol (VoIP), digital Internet voice calling services; however, early versions of the Asterisk software are known to have a vulnerability. The vulnerability can be exploited by cyber criminals to use the system as an auto dialer, generating thousands of vishing telephone calls to consumers within one hour.

The vulnerability referred to in this alert is a known vulnerability. Digium, the original creator and primary developer of Asterisk, released a Security Advisory, AST-2008-003, in March of 2008, which contains the information necessary for users to configure a system, patch the software or upgrade the software to protect against this vulnerability.

If a consumer falls victim to this exploit, their personally identifiable information (PII) will be compromised. To prevent further loss of consumers' PII and to reduce the spread of this new technique, it is imperative businesses, using Asterisk, upgrade their software to a version that has had the vulnerability fixed.

Further, consumers should not release personal information in response to unsolicited telephone calls. Providing your PII will compromise your identity!

If you have been a victim of Internet crime, please file a complaint at

  1. Vishing utilizes caller ID spoofing via VoIP to contact potential victims in order to gain access to their PII by convincing the victim that the criminal is associated with a legitimate business with a need to know the victim's PII.
  2. PBX Systems are used by companies to allow telephone calls between VoIP enterprise users on local lines while allowing all users to share a limited number of external lines.