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What's the difference between a SIP-flood attack and a TDoS attack?

While SIP-flood attacks and TDoS attacks have similar goals, their attack vectors are very different. Industry expert Michael Brandenburg explains.

What's the difference between a SIP-flood attack and a telephony denial of service (TDoS) attack? Are they the...

same thing?

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While both types of attacks have a similar goal in disrupting unified communications (UC) platforms, the attack vector the two methods use is very different. In the case of a TDoS, the attack vector is the target's telephone numbers. By flooding a company's phone circuits with fraudulent inbound calls, a TDoS attack can ultimately prevent legitimate calls (and potential customers) from ever reaching the target business. Without some form of countermeasure, this type of attack can affect everything from the oldest of PBXs to the newest of cloud-based hosted UC platforms.

A SIP-based attack, on the other hand, is a decidedly network-driven attack, and is similar to the types of attacks inflicted upon Internet Web servers. In the case of a SIP-flood, seemingly valid SIP protocol requests attempt to either gain access as a remote endpoint or inundate the UC platform and its endpoints with so many requests that the systems or devices crash, which ultimately disrupts services or exposes vulnerabilities.

Because the two types of attacks target the system in different ways, each has its own way of mitigation. SIP-based attacks might be identified and thwarted by E-SBCs deployed at the network edge to provide flood detection as well as obfuscation of network resources. TDoS attempts, on the other hand, may require call blocking and other tools available from your carrier.

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