Threats to VoIP

Numerous threats to VoIP networks exist, and many of these are similar to threats facing traditional PBX systems. VoIP network threats include:

Theft and toll fraud Toll fraud is the theft of long-distance telephone service by unauthorized access to a PSTN trunk (that is, an "outside line") on a PBX or voice mail system. Toll fraud is a multibillion-dollar illegal industry, and all organizations are vulnerable. Theft can also be defined as the use of the telephony system, by both authorized and unauthorized users, using voice-network resources to access unauthorized numbers, such as 900 billable numbers.

Unauthorized access to voice resources Hackers can tamper with voice systems, user identities, and telephone configurations and also intercept voice mail messages. If hackers gain access to the voice mail system, they can change the voice mail greeting, which negatively impacts the image and reputation of the company. A hacker who gains access to the PBX or voice gateway could potentially shut down voice ports or change voice-routing parameters, affecting voice access into and through the network.

Compromise of network resources The goal of a secure network is to ensure that applications, processes, and users can reliably and securely interoperate using the shared network resources. Because the shared network infrastructure carries both voice and data, security and access to the network infrastructure is critical in securing voice functions. Because VoIP systems are installed on a data network, they are potential targets for hackers who previously targeted only PCs, servers, and data applications. Hackers are aided in their search for vulnerabilities in VoIP systems by the open and well-known standards and protocols used by IP networks.

Denial-of-service (DoS) attacks DoS attacks are defined as the malicious attacking or overloading of call-processing equipment to deny access to services by legitimate users. Most DoS attacks fall into one of the following categories:
- Network resource overload Overloading a network resource that is required for proper functioning of a service. The targeted network resource is most often bandwidth. The DoS attack uses up all available bandwidth, preventing authorized users from accessing the required services.

- Host resource starvation Using up critical host resources. When use of these resources is maximized by the DoS attack, the server can no longer respond to legitimate service requests.

- Out-of-bounds attack Using illegal packet structure and unexpected data, which can cause the operating system of the remote system to crash. One example of this type of attack might be to use illegal combinations of TCP flags. Most TCP/IP stacks are developed to respond to appropriate use. They are not developed for anomalies. When the stack receives illegal data, it might not know how to handle the packet and might cause a system crash.

- Eavesdropping Eavesdropping involves the unauthorized interception of voice packets (that is, RTP media streams). Eavesdropping can expose confidential or proprietary information that is obtained by intercepting and reassembling packets in a voice stream. Numerous tools are used by hackers to eavesdrop.

Threats to VoIP

Threats to VoIP

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