Story image

The perils of VoIP

01 Dec 10

You may be confident that your computer system is secure from intruders, but have you ever thought about your phones?
More businesses are switching to internet-based, or VoIP, services these days and many don’t realise that VoIP systems, if not properly secured, can be hacked. "Once you’ve got access to the company’s network, then you can often eavesdrop on phone calls, harvest voicemail, make free calls; you can even impersonate people,” says John McColl, consultant for
The easiest way into a company’s VoIP phone system for a hacker, is through the port used by the session initiation protocol (SIP) to initiate calls. That port, numbered 5060, is the one hackers look for and if it is left open, it’s tantamount to inviting them in.
The most common form of abuse of hacked VoIP systems comes through premium (especially long-distance) phone calls. Businesses often don’t discover these intrusions until they receive their phone bill. Australian network companies have told of clients getting bills for $100,000 worth of unauthorised calls placed over compromised VoIP servers. Access codes are also fetching big money on the black market; a single code can be on-sold numerous times, at around $US100 a pop.
But the potential for industrial espionage through phone hacking is obvious. "If I wanted to find out trade secrets I’d hack your VoIP,” says McColl. Imagine the damage that could be done if a hacker tapped into an important meeting being conducted by audio or video conference.
Such hacking could even compromise a building’s security. The hacker could call the security desk, telling the guard to let certain people in. The guard sees only the extension name and number of the caller, which looks genuine because the hacker has logged into the system as a legitimate user.
Skype calls are generally encrypted, so they don’t pose such a big security risk, but open source systems like Asterisk need special protection. ‘Soft phones’ that work through PCs are another point of vulnerability.
To protect your phone system, you need a complete strategy. If staff are required to enter a password or PIN number to make their phones work, make sure they are not easy to guess (some businesses just leave the extension number as the PIN).
To protect Port 5060, your server’s firewall needs to know who has access to it. Your VoIP service provider should be the only authorised user. An added protection is to give your provider each individual phone’s media access control (MAC) address (this is usually printed on the back of the phone).

The key to financial institutions’ path to digital dominance
By 2020, about 1.7 megabytes a second of new information will be created for every human being on the planet.
Is Supermicro innocent? 3rd party test finds no malicious hardware
One of the larger scandals within IT circles took place this year with Bloomberg firing shots at Supermicro - now Supermicro is firing back.
Record revenues from servers selling like hot cakes
The relentless demand for data has resulted in another robust quarter for the global server market with impressive growth.
Opinion: Critical data centre operations is just like F1
Schneider's David Gentry believes critical data centre operations share many parallels to a formula 1 race car team.
MulteFire announces industrial IoT network specification
The specification aims to deliver robust wireless network capabilities for Industrial IoT and enterprises.
Google Cloud, Palo Alto Networks extend partnership
Google Cloud and Palo Alto Networks have extended their partnership to include more security features and customer support for all major public clouds.
DigiCert conquers Google's distrust of Symantec certs
“This could have been an extremely disruptive event to online commerce," comments DigiCert CEO John Merrill. 
Schneider Electric's bets for the 2019 data centre industry
From IT and telco merging to the renaissance of liquid cooling, here are the company's top predictions for the year ahead.