Sipera VIPER Lab disclosed multiple threat advisories for users of VoIP services and equipment from Vonage, Globe7 and Grandstream. Among other threats, unwitting VoIP users face eavesdropping, spam, spoofing and denial-of-service (DoS) attacks. Full details on these vulnerabilities are posted as an educational security service to Sipera's customers and the general public at http://www.sipera.com/viper.

Sipera VIPER Lab determined the Vonage VoIP Motorola Phone Adapter (VT 2142-VD) and Vonage service implementations leave users vulnerable to a form of VoIP identity theft, allowing hackers to take over a user's phone service with a "registration replay attack," then make and receive calls while impersonating the victim. Incomplete security practices, such as not encrypting traffic, open Vonage users to eavesdropping on private voice and video communications. Hackers can also send multiple SIP INVITE messages to a user, an Internet version of "ringing the phone off the hook" which creates a DoS attack. Leveraging these vulnerabilities, remote attackers can also send malicious messages directly to Vonage users, subjecting them to spam, social engineering and VoIP scams.

Sipera VIPER Lab also found issues with European provider Globe7's online account access, as a result of utilizing unsecured connections and employing a weak encryption scheme. This allows hackers to access confidential name, password and account balance data, as well as steal VoIP service to make and receive calls, masked as a legitimate Globe7 user. Likewise, Sipera VIPER Lab established the Grandstream HandyTone-488 PSTN-to-VoIP adapter is vulnerable to buffer overflows and fragmented packet attacks. By sending a specially crafted SIP INVITE message to public IP addresses, attackers can disconnect legitimate Grandstream users.

Sipera VIPER Lab is comprised of experienced VoIP security researchers operating globally 24/7/365. Since its inception in 2003, Sipera VIPER Lab has identified thousands of vulnerabilities and security threats which include fuzzing, floods and distributed floods, spoofing, stealth attacks and spam. VIPER Lab research is used to continuously improve the Sipera IPCS products that protect, control and enable real-time unified communications for enterprises and service providers. Sipera VIPER Lab also recently launched a blog to discuss ongoing VoIP attacks and VoIP/UC vulnerabilities at http://www.sipera.com/viper/blog.