While Vonage defends itself against patent lawsuits from the likes of AT&T, the pioneering VoIP company also faces new risks from hackers.
Sipera Systems, a VoIP security company, said on Tuesday that users of VoIP services and equipment from Vonage, Globe7 and Grandstream were vulnerable to eavesdropping, spam, spoofing, and denial-of-service (DoS) attacks.
"These vulnerabilities create serious privacy and service availability issues for users," said Krishna Kurapati, Sipera founder and CTO, in a statement. "Vonage, Globe7 and Grandstream customers can no longer assume that their VoIP providers are automatically securing their services, but they should demand best security practices be followed as a condition of becoming a customer."
The Vonage VoIP Motorola Phone Adapter (VT 2142-VD), for example, does not authenticate SIP requests, leaving its vulnerable to VoIP identity theft, Sipera said. An attacker exploiting this vulnerability could send and receive calls using the victim's account. An attacker could also send multiple SIP INVITE messages, in effect creating a denial-of-service attack. Furthermore, an attacker could send spam and phishing messages directly to the hacked Vonage user.
The Grandstream HandyTone-488 PSTN-to-VoIP adapter is vulnerable to buffer overflow and fragmented packet attacks, Sipera said. The device's flaws could be exploited to conduct denial-of-service attacks.
Finally, the Globe7 VoIP Client does not use a secure connection, making it possible for an attacker to eavesdrop on calls, according to Sipera. The company also warned that the Globe 7 soft phone uses a weak encryption scheme that leaves the user's account information vulnerable to theft.