And, of course, let's not forget about the new telecommunications technologies which are based around open communications via the Internet. These include IP-driven PBXs supported by all the adjunct devices, the deployment of CTS (Computerised Telephone Systems), CTI (Computer Telephony Integration) and Voice over IP. The introduction of these technologies means IT and telecoms managers need now to become even more alert to prevent new and existing threats that are typically associated with data networks, now impacting upon voice networks. Without diligent attention, telecoms systems are in grave danger of becoming the weak link in the network and utterly defenceless against targeted attacks by hackers.
So what practical measures can telecom or IT managers take to help prevent becoming a victim of telecom fraud?
One of the most effective approaches to improving the security of telephony systems includes conducting regular audits of:
- Station privileges and restrictions
- Voice and data calling patterns
- Public and private network routing access
- Automatic route selection
- Software defined networks
- Private switched and tandem networks
- System management and maintenance capabilities
- Auto attendant and voicemail
- Direct inward system access (DISA)
- Call centre services (ACD)
- Station message detail reporting
- Adjunct system privileges
- Remote maintenance protection
- Primary cable terminations and physical security of the site and equipment rooms
Ensure default voicemail and maintenance passwords are changed and introduce a policy to prevent easily guessable passwords being used. Make sure that the policy demands regular password changes and take steps to ensure the policy is enforced.
Installing a call logging solution, to provide notification of suspicious activity on your PBX, is a useful measure and one that can often give valuable early warning of an attack. In addition, review existing PBX control functions that might be at risk or which could allow errors to occur.
Be aware that many voice systems now have an IP address and are therefore connected to your data network. You therefore must assess what provisions you have to segment both networks. Security exposures can also result from the way multiple PBX platforms are connected across a corporate network or from interconnectivity with existing applications.
Research and investigate operating system weaknesses, including analytical findings, manufacturer recommendations, prioritisation and mitigation or closure needs - and implement a regular schedule of reviewing server service packs, patches, hot-fixes and anti-virus software.
Finally, formalise and instigate a regular testing plan that includes prioritisation of the elements and components to be assessed, and supplement this by conducting a series of probing exercises to confirm the effectiveness of the security controls used.
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