7 Ways to Stop VoIP DDoS Attacks from Crashing Your Phones

Distributed Denial of Service (DDoS) attack vector attempts to flood VoIP servers with fake user requests. Because this amount of traffic exceeds the capacity of your network, it can force your online service or website offline, preventing legitimate user requests from being processed.

Cybercriminals can use them to compromise your Voice over Internet Protocol (VoIP) network service, which forms the backbone of most modern business phone services and call center software.

VoIP services are highly vulnerable to DDoS attacks because attackers do not have to take them offline to disrupt communications—an ultimately failed VoIP DDoS attack can still severely degrade voice call service.

An attacker can bring down a business phone system in seconds. Think of the damage done to popular brands during the holiday shopping season, or to power companies during power outages.

Let’s take a look at how these attacks occur and what specific steps you can take to defend against them.

Anatomy of a VoIP DDoS Attack

Distributed Denial of Service Attack The web is flooded with enough fake traffic to crash anything online, such as a website, app, or phone service. Legitimate users were denied service because the network was busy processing an overwhelming number of bogus requests.

It’s easy to imagine that a VoIP server that handles hundreds of calls per hour would run into some serious problems when responding to a sudden surge of thousands of calls per second.

Attackers use large robot networks of interconnected devices, also known as botnets, to carry out these attacks. Typically, these are infected devices, including computers, routers, mobile phones, and IoT devices (smart homes and wearables). Modern criminal botnet Ability to perform numerous repetitive actions to further DDoS attacks, spam campaigns and Credential Stuffing Attack.

Simply put, a VoIP DDoS attack is when a large amount of junk traffic hits your network, making it impossible for legitimate traffic to be processed. This could result in service outages, network crashes, or escalate into a ransomware attack that can paralyze business-critical systems until you pay.

Hackers often target (Session Initiation Protocol), Protocol used to start VoIP. They can send a large number of SIP call requests, causing the victim’s VoIP server to crash. This is called a SIP flood attack.

Another common tactic is a SIP reflection attack, in which the threat actor sends a request to thousands of random servers but spoofs the victim’s IP address in the SIP request. These servers send responses back to the victim, whose VoIP server is now flooded with requests.

How to protect against VoIP DDoS attacks

any one Best Business Phone Service Provider These defenses and more have been implemented. Businesses using these services should discuss with their providers the best ways to deal with VoIP DDoS threats and the steps the provider is taking to ensure network security from the latest threats.

If you’re responsible for infrastructure, here are seven ways to protect your network from VoIP DDoS attacks.

1. Use a reverse proxy

Rather than allowing clients and web requests to interact directly with servers, reverse proxies sit in front of them and intercept their messages. Therefore, a reverse proxy protects the server by processing and filtering requests on the server’s behalf. That’s why they are also called gateway servers.

Because the reverse proxy server Receives HTTP endpoint requests for origin servers, which can improve security, reliability, and performance. Therefore, you can use a reverse proxy to protect your server from DDoS and external attacks.

Here are some specific ways reverse proxy servers protect your infrastructure from DDoS attacks:

• Policing inbound traffic to ensure only legitimate traffic is allowed through.
• Protect your critical resource servers (web, application and database servers).
• They mask the IP address of your origin server, making it harder for hackers to target it.
• Reduce latency by offloading some of the computational load on the origin server, such as encrypting and decrypting Transport Layer Security (TLS/SSL) communications.
• They use load balancing and network acceleration to improve user experience.
• They improve server performance through the use of rate limiting, content caching, and load balancing.

2. Deploy real-time, adaptive network monitoring

this The best network monitoring tools Can help prevent DDoS attacks through the ability to detect abnormal network activity in real time. It’s not just rote network monitoring, it can also detect anomalous behavior in a network after establishing a baseline of typical activity as a reference point.

As a result, your network security defenses can better adapt to abnormal traffic spikes caused by DDoS and protect endpoint protocols and IP blocks from malicious requests.

In addition to preventing VoIP DDoS attacks, these real-time network monitoring can also help Prevent VoIP Scams.

3. Implement rate limiting

Once network monitoring has established a baseline of network activity, you can implement rate limiting, a strategy for limiting network traffic to prevent malicious bot activity and any other consequences of a DDoS attack, such as system resource exhaustion and overuse. .

Rate limiting works by delaying or completely blocking requests from a single IP address or multiple traffic sources, especially when they exceed a threshold.

Rate limiting is implemented in a variety of ways to ensure that only legitimate traffic is allowed. For example, they ensure that a consumer, agent, or endpoint cannot repeat an action or activity within a specific period of time, essentially limiting the number of requests that can be made to a resource. The overall impact of rate limiting makes it more difficult for attackers to launch successful DDoS attacks.

Generally speaking, rate limiting allows you to customize the total number of requests allowed to a given server within a specified time frame. This functionality is usually provided in reverse proxy servers.

4. Reduce attack surface

The less infrastructure exposed, the harder it is for criminals to hit their targets. Therefore, reducing attack scope involves minimizing the range of available options for attacking computing resources, whether they are entry points, ports, protocols, network channels, or servers.

There are several ways to reduce your attack surface, as follows:

• You should limit traffic only to countries with the largest number of users.
• Use load balancers and reverse proxies to protect your servers.
• Allocate key assets to make goals more challenging. For example, you can separate web servers by placing a public-facing application server on a public subnet while isolating its underlying database server on a private subnet.

Please see: for more specific information VoIP Security Best Practices This reduces your attack surface.

5. Strengthen VoIP network security

There are many ways to harden a VoIP network against DDoS attacks. Although you should always consider Set up firewall As a matter of first order, these are low-hanging fruit for cyber defense. As investors diversify their portfolios to minimize risk, you should spread your servers across multiple data centers and networks for better load balancing and fault tolerance.

Instead of traditional firewalls, a better approach is to opt for a more sophisticated web application firewall (WAF) or Next Generation Firewall (NGFW) It’s better at protecting against DDoS attacks and other common application vulnerabilities, such as cross-site request forgery. It also offers threat prevention technology, such as custom rule sets that let you customize how incoming traffic is filtered for increased security.

6. Implement black hole routing

Although blackhole routing (sometimes called “blackhole”) is a reactive DDoS defense technology, if implemented properly, it can stop attacks by dropping or redirecting malicious traffic.

As the name suggests, blackhole routing prevents illegal traffic from reaching its desired destination by redirecting it to empty interfaces or “black holes.” Additionally, this can be done without the hassle of notifying the source that their data did not reach the intended target, leaving criminals in the dark about the effects of their attack.

7. Bandwidth oversubscription

This involves organizations leasing more bandwidth than they normally need. However, this “oversubscription” is unlikely to cause financial harm to the company because of its ability to obtain favorable terms.

Granted, this isn’t a practical option for most organizations, but if you’re an enterprise company, you should consider purchasing more bandwidth to mitigate the potential impact of a DDoS attack. Therefore, increasing the size of your network provides a buffer, giving you room to mitigate DDoS attacks.

One last note: Last resort VoIP DDoS defense strategies can only stop a limited number of attacks – if you are subject to a full-blown professional attack, any additional bandwidth you purchase will be quickly exhausted.

In other words, oversubscription can be a useful hedge for some businesses, especially as part of a strong overall cybersecurity architecture.