The Public Switched Telephone Network PSTN is a global system of interconnected, various analog sized phone networks which provides users the capability to carry voice conversations with each other. Initially, the most basic analog network service, called POTS Plain Old Telephone Service , used a pair of twisted copper wires in order to connect a residential phone to a central office from where a residential customer can dial out in the PSTN.
Initially, the PSTN was a simple one-to-one telephone line connecting phones from one room to another. When telephone business grew, Private Branch eXchanges PBX were designed, and deployed in office settings to provide the increasing of telephone lines and to connect internal callers over trunk lines through either the PSTN or eventually to destination callers.
TDM transmits and receives independent signals over a common signal path by means of synchronized switches at each end of the transmission line, so that each signal appears on the line only a fraction of a time in an alternating pattern. Voice over Internet Protocol VoIP is a newer technology that allows phone conversations to be transferred over the computer networks, it transforms analog and digital audio signals in data packets. VoIP has seen rapid implementation over the past few years, many users choose VoIP and leave behind the traditional telephonic providers in order to pay cheaper bills; for companies using VoIP is an easy way for communication between their several branches and for their teleworking employees.
VoIP services are often taken in use but their security threats are analyzed only under specific aspects or not taken in consideration at all. This article analyzes the most common VoIP threats in order to identify existing weaknesses and suggests available countermeasures.
The results of this article could be used by system administrators, network engineers and penetration tester in order to examine their VoIP systems. The author of this paper discharge all responsibilities for an inappropriate use of the information here reported and suggests to try these attack techniques only in controlled environments, like test plants, and with previous authorization of the owner.
VoIP Fundamental Protocols. Figure 1. Classic VoIP network scenario. The protocol provides facilities for jitter compensation jittering is rather common on a Packet-Switched Network since communication is provided by network Routers , detection of out of sequence arrival in data and allows data transfer to multiple destinations through IP multicast.
Real-time applications require timely delivery of information and can tolerate some packet loss usually than an excessive delay. The audio sampling rate is typically either Hz or Hz and the rate that RTP packets are transmitted is determined by the audio Codec by mean of its Packetization Period.
Whether those packets actually arrive at a fixed rate at the receiving endpoint depends on the network performance. RTP packets might be lost by Routers, might arrive at the receiving endpoint out of sequence, or could be even duplicated when they transit through the network. Hence receiving endpoints are designed with the assumption that RTP packets will not arrive at the precise rate they were transmitted.
About this reasons an endpoint incorporate a Jitter Buffer having parameters in order to manipulate the characteristics of time buffering in an attempt to produce the highest Quality of Service during the playback. Jitter Buffer uses RTP header information to accomplish its functions. SIP sessions involve one or more participants and can use either unicast or multicast communication.
SIP is text-encoded and highly extensible since it may be extended to accommodate features and services such as call control services, mobility and interoperability with existing telephony systems. That are 4 types of logical SIP entities, each one participates in SIP communication as a client the entity which initiates the Requests , as a server the entity which Responds to Requests , or as both.
One network device can have the functionality of more than one logical SIP entity. But, the Colombian university professor said:. The company plans to issue a security advisory and a detailed mitigation document later this week. They also showed this particular hack worked so do have a look at the presentation. Follow HackRead. Author Waqas. Simply walking into a bank and ask for a phone and almost everyone will not think twice to leave you unattended with the phone.
At 20 employees, Ontario based VoIPshield is working to establish itself as a security vendor. The company wields lots of power on the market because they're unique and the first ones to do this, but its technology is largely unknown. Like the more established data security vendors, VoIPshield is using its security alerts to gain the vendors' respect and market trust.
VoIPaudit performs security audit on VoIP infrastructure by automatically discovering devices and services. The product also tests for vulnerabilities. VoIPguard arrives with two detection engines. One engine is signature based and relies on discovered vulnerabilities in its database. The other engine is much smarter and attempts to discern traffic to find whether it's malicious or not.
The smart engine looks at traffic going through logging events, studies protocols and general IP-PBX traffic behavior. Both products are fed with updates as part of a subscription service. Each of the VoIP hacks listed above are costly for businesses. Most VoIP vulnerabilities can be eliminated with better awareness, regular education, and proactive steps your internal team can take to strengthen your defenses. A weak provider makes it easier for hackers to infiltrate your phone network and gain access to private information.
They should be able to give you this information on request. Administrative access to your VoIP infrastructure means the user can control everything related to your business phone system.
The user can manage billing, join conference calls, set up new lines, and lead to more costly intrusions. You should be extremely careful with which employees get administrative access to your VoIP phone system. Giving everyone access increases the likelihood of a social engineering attack. People make mistakes, but with proper permissions, their impact is limited. The more employees there are to persuade, the more at-risk you are of falling victim to a scam and giving the hacker administrative access to your network.
Those remote staff communicate with their coworkers and customers via phone, which makes them vulnerable to VoIP hacking. Your remote team installs a VPN on their work devices—including their smartphone or softphone. That makes it almost impossible for hackers to eavesdrop on the calls your remote workforce are making. This limits connectivity to malicious sites.
VPN providers such as Sophos and Cisco use endpoint filtering to block the network from accessing sites that could download malware, or handing over information hackers can use against you, such as a public IP address. This strengthens overall network connectivity and device integrity. There are a number of solutions out there which provide this added layer of protection. However, doing this leaves you at risk for a VoIP hack. Regularly checking your network allows you to spot any holes in your VoIP security.
Administrators should regularly evaluate access and best practices to avoid compromise. Your IT department should also conduct an annual security check. This "penetration test" simulates a hacker and determines whether the network is secure. Any potential weaknesses should be reviewed and fixed as soon as possible. A call log is the history of incoming and outgoing calls your business has made. You can easily see whether your VoIP phone system has been hacked with these logs.
Any anomalies that might signal a hack can be spotted—even before your call limits stop them. Similarly, an access log shows who has signed into your VoIP phone system.
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