The Channel logo


By | John Leyden 16th June 2015 14:58

Phone hacking blitz hammers's poor VoIP handsets

If I ever get my hands on those phreaking kids who hacked my phones...

UK businesses are getting disproportionately targeted by a surge of attacks against Voice over IP (VoIP) systems.

The growing use of VoIP technology in business and a greater availability of hacking tools that dumb down the process of hacking into systems has led to an increase in attacks worldwide.

UK-based systems are being hit particularly hard, according to a new study by security consultancy Nettitude.

During the first quarter of 2015, Nettitude's security researchers observed a large amount of VoIP attacks worldwide: however, the majority were against UK servers. VoIP attacks often started just a few minutes after a new server went live.

Nettitude researchers found that 88 per cent of VoIP attacks took place outside of regular working hours, when there would typically be no staff present to monitor the situation. The research (pdf) also explains the tools and techniques that are being used by today’s VoIP attackers. In particular, Nettitude analysed a tool called SIPVicious (a name apparently referencing the Sex Pistols' late bassist Sid Vicious).

Although the tool is designed to be used in auditing SIP systems (Session Initiation Protocol, the core technology for setting up VoIP voice communications), but it can also be used to determine the VoIP system a target is using and in running brute-force password cracking attacks.

Service abuse and toll fraud have long been the most common objective of VoIP hackers or phone system phreakers. Premium Rate Service (PRS) fraud is becoming more and more prevalent, according to Nettitude.

"We recorded a large number of calls to premium numbers and foreign numbers. Such actions can have serious financial impacts on the organisation being attacked," Nettitude reports.

The penetration testing firm notes logging a large number of failed password attempts on systems it monitors.

"The large number of failed attempts to log into the system, register and make calls affected the performance of the system. Such behaviour could cause denial of service, making the services unavailable for legitimate users," Nettitude adds.

It's not just tool fraud. Other forms of attack against VoIP systems including disruption of service and eavesdropping are also starting to crop up.

A representative of a different UK security consultancy we recently spoke to said it had come across a case seemingly involving eavesdropping into VoIP conference calls. The suspected attack is still under investigation.

"The attack took place from within the network and was targeting their internal VoIP phones. This involved changing the VoIP phone settings to 'listen' mode, enabling the attackers to listen in on calls made physically from specific VoIP phones located in targeted meeting rooms," our contact told us.

Six categories of threats are recognised by the industry group the Voice over IP Security Alliance (VOIPSA). ®

comment icon Read 14 comments on this article or post a comment alert Send corrections


Frank Jennings

What do you do? Use manual typwriters or live in a Scottish croft? Our man advises
A rusty petrol pump at an abandoned gas station. Pic by Silvia B. Jakiello via shutterstock

Trevor Pott

Among other things, Active Directory needs an overhaul
Baby looks taken aback/shocked/affronted. Photo by Shutterstock

Kat Hall

Plans for 2 million FTTP connections in next four years 'not enough'
Microsoft CEO Satya Nadella


League of gentlemen poster - Tubbs and Edward at the local shop. Copyright BBC
One reselling man tells his tale of woe