Hackers could use VoIP phones to eavesdrop on you

Hackers could listen in on you via your VoIP phone, security researchers have warned.

By using a simple exploit taking advantage of weak default passwords, attackers can hack your VoIP phone to make and receive calls, transfer calls without your knowledge and even spy on your in-person conversations.

Security expert Paul Moore discovered the flaw after consulting on the installation of several VoIP phones.

During the process, he noticed installers and IT professionals neglecting to change the default passwords, saying that they would do "for now".

"Of course, as soon as the device burst into life, it's on to the next one," he said. "At which point, 'now' becomes a distant memory, along with any thoughts of hardening the device for use in a commercial setting."

One major problem Moore highlighted was a lack of device-level authentication.

He noted that the equipment was from well-known and trusted industry names such as Cisco, Snom and Ubiquiti UniFi, but said that although these brands are often assumed to be secure when placed behind a firewall, this is not necessarily the case.

With the help of fellow security professionals Per Thorsheim and Scott Helme, he demonstrated how easy VoIP phones are to hack.

Moore reset a Snom 320 VoIP phone to its factory default settings, and the only thing the attacker needed to do in order to gain complete control of the device was to visit a site infected with a malicious payload.

Once infected, the hacker has complete control over the phone, allowing them to block incoming calls, silently call premium-rate numbers, and secretly listen in on a user's conversations.

Moore has called for manufacturers to take better care in securing their products before sending them out into the wild.

"Vendors," he said, "if you must supply devices with 'default' credentials, disable all other functionality until a suitably-secure password is set to replace it".

He also urged IT staff to be aware of the dangers posed by any internet-connected appliance.

"If you install, use or just find yourself sat next to one of these devices," he advised, "just remember... it's basically a PC, with all the security vulnerabilities associated with them."

"Don't assume it's safe because it's running as the manufacturer intended; seek professional advice."

Adam Shepherd

Adam Shepherd has been a technology journalist since 2015, covering everything from cloud storage and security, to smartphones and servers. Over the course of his career, he’s seen the spread of 5G, the growing ubiquity of wireless devices, and the start of the connected revolution. He’s also been to more trade shows and technology conferences than he cares to count.

Adam is an avid follower of the latest hardware innovations, and he is never happier than when tinkering with complex network configurations, or exploring a new Linux distro. He was also previously a co-host on the ITPro Podcast, where he was often found ranting about his love of strange gadgets, his disdain for Windows Mobile, and everything in between.

You can find Adam tweeting about enterprise technology (or more often bad jokes) @AdamShepherUK.