FBI Warns of New Vishing Attacks Targeting Private Branch Exchange Systems

The FBI has identified a new technique used to conduct vishing attacks where hackers exploit a known security vulnerability in Asterisk software. Asterisk is free and widely used software developed to integrate Private Branch Exchange (PBX) 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.

Digium, the original creator and primary developer of Asterisk, released a security advisory (AST-2008-003) in March 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 that 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.

"As with all types of scams, whether by computer, phone, or mail, using common sense can protect you," said Special Agent Richard Kolko, chief, National Press Office, Washington, D.C.