What is a flood attack?

A flood attack, often a form of Distributed Denial of Service (DDoS) attack, aims to overwhelm a system with superfluous requests, thus preventing legitimate requests from being fulfilled. The primary objective is to make the target service unavailable, either by consuming all its resources or crashing it altogether. Flood attacks exploit the limitations of a network’s bandwidth, memory, and processing power. By sending an excessive number of requests, they can exhaust these resources rapidly, causing severe disruptions. Attackers often use botnets, a network of compromised devices, to generate the enormous volume of traffic required for such attacks, making it harder to trace and block the sources.

How does it work?

A flood attack works by sending a massive volume of traffic to a targeted server, service, or network. This traffic often appears to be from legitimate users, which makes it challenging to distinguish and filter out. The target system gets overwhelmed by this surge in requests, which eventually leads to its degradation or shutdown. Flood attacks can be executed through various protocols and methods, such as TCP, UDP, ICMP, and HTTP, each exploiting different aspects of the network’s communication process. Advanced flood attacks may use randomization techniques to avoid detection and mitigation efforts, making them more sophisticated and harder to counter.

Why is flood attack dangerous?

• Disruption of service: The most immediate impact is the service disruption. Websites may become unavailable, networks may slow down, and businesses may experience downtime.
• Financial impacts: With downtime comes lost revenue. Especially for businesses that rely heavily on online services, a few minutes of inaccessibility can translate to significant financial losses.
• Damage to reputation: Continuous attacks can tarnish a company’s reputation, causing loss of customer trust and loyalty.
• Resource consumption: An immense amount of resources, both human and technological, need to be diverted to handle the aftermath of such attacks.
• Diversion: Sometimes, attackers use flood attacks as a smokescreen, diverting attention from a more covert breach or intrusion.

How to mitigate it?

• Monitoring: Continuous monitoring of network traffic can help in early detection of unusual traffic spikes, which may indicate a flood attack. Tools like intrusion detection systems (IDS) can be invaluable.
• DDoS Protection: DDoS protection services can help mitigate the effects of a flood attack. These services often use a combination of traffic filtering, rate limiting, and other tactics to ensure only legitimate traffic reaches the target. 
• Secondary DNS: If the primary DNS server becomes overwhelmed due to a flood attack, the secondary DNS server can continue to resolve domain names, ensuring that services remain accessible to legitimate users.
• Firewalls and Routers: Properly configured firewalls and routers can help filter out malicious traffic.
  Router vs firewall
• TTL Analysis: Investigate the TTL values on incoming packets. Abnormal TTLs can indicate potential malicious traffic.
• IP Blocklisting: Identify and block IPs that show malicious activity. This prevents them from accessing your systems further.
  Whitelisting vs Blacklisting

Types of flood attack

DNS Flood Attack

A DNS flood attack specifically targets the Domain Name System (DNS) servers. The DNS is the internet’s phonebook, translating human-friendly URLs (like “example.com“) into IP addresses that computers use to identify each other on the network (like “1.2.3.4”). In a DNS flood attack, attackers send a high volume of DNS lookup requests, usually using fake IP addresses. This causes the DNS servers to try and resolve each request, leading to an overwhelming number of processes. This congestion ensures that genuine requests from real users either get significantly delayed or ignored altogether. If an attacker successfully disrupts a DNS server, it can make a whole swath of websites or online services inaccessible.

SYN Flood Attack

To understand a SYN flood attack, one must first grasp the “three-way handshake” process used to establish a TCP connection. The sequence is SYN, SYN-ACK, and ACK. In a SYN flood attack, the attacker sends a rapid succession of SYN requests but either does not respond to the SYN-ACK replies or sends them from spoofed IP addresses. The target system will keep these connections open, waiting for the final ACK that never comes. This can consume all available slots for new connections, effectively shutting out legitimate users.

HTTP Flood Attack

HTTP flood attacks take advantage of the HTTP protocol that web services operate on. In this attack, a massive number of HTTP requests are sent to an application. Unlike other flood attacks, the traffic sent looks legitimate. The requests can be either valid URL routes or a mixture with invalid ones, making them harder to detect. Because the requests look so much like typical user traffic, they’re particularly difficult to filter out. This method can exhaust server resources and cause legitimate requests to time out or receive delayed responses.

ICMP (Ping) Flood Attack

ICMP, or Internet Control Message Protocol, is a network protocol used by network devices to send error messages. The “ping” tool uses ICMP to test the availability of network hosts. In a Ping flood attack, attackers inundate the target with ICMP Echo Request (or ‘ping’) packets. The target then tries to respond to each of these requests with an Echo Reply. If the attack is voluminous enough, the target system’s bandwidth or processing capabilities may get overwhelmed, causing a denial of service.

Suggeted page: The function of ICMP Ping monitoring

UDP Flood

User Datagram Protocol (UDP) is a sessionless networking protocol. In a UDP flood attack, the attacker sends many UDP packets, often with spoofed sender information, to random ports on a victim’s system. The victim’s system will try to find the application associated with these packets but will not find any. As a result, the system will often reply with an ICMP ‘Destination Unreachable’ packet. This process can saturate the system’s resources and bandwidth, preventing it from processing legitimate requests.

Impact of Flood attacks on different industries

Flood attacks can have devastating effects across various industries, each facing unique challenges and potential damages:

E-commerce:

E-commerce platforms rely heavily on their websites for sales and customer interaction. A flood attack can cause significant downtime, leading to lost sales, decreased customer trust, and potential long-term damage to the brand’s reputation. Additionally, the costs associated with mitigating the attack and enhancing security measures can be substantial.

Suggest: Global Reach, Local Touch: The Role of GeoDNS in eCommerce Expansion

Finance:

In the finance sector, the availability and integrity of online services are critical. Flood attacks can disrupt online banking, trading platforms, and payment processing systems. This not only affects customer transactions but can also lead to compliance issues and regulatory scrutiny. The financial losses and impact on customer confidence can be severe.

Healthcare:

Healthcare providers use online systems for patient management, medical records, and telemedicine. A flood attack can interrupt these services, potentially putting patient health at risk. Delayed access to medical records and appointment scheduling can cause significant operational disruptions and affect the quality of care provided.

Gaming:

The gaming industry is a frequent target of flood attacks, especially during major events or game launches. These attacks can disrupt gameplay, causing frustration among users and leading to a loss of revenue for gaming companies. The competitive nature of online gaming also means that downtime can significantly impact player engagement and retention.

Conclusion

Flood attacks are among the oldest tools in a hacker’s arsenal, but they remain effective. As the digital landscape grows and evolves, so do the methods attackers employ. Regularly updating security infrastructure, staying informed about emerging threats, and employing a proactive defense strategy can go a long way in keeping systems secure and operational.

The post Flood Attack: Prevention and Protection appeared first on ClouDNS Blog.

What is a DNS attack? How can it affect me? 

The name says it, an attack that targets the Domain Name System (DNS). It can have a different purpose: trying to destabilize it, bring it down, alter information, or another. The DNS is old, and, as you could guess, by itself, it is not the safest infrastructure in the world. But there are extra measures that can really help. 

Imagine these two scenarios so you can understand it easier:

1. The cybercriminal redirects the traffic that should go to your site, to one that he or she controls. He or she can have a fake page, mimicking yours and steal valuable data from your clients, pretending to be you. The unaware client, do what he normally does. Register and use the page to buy or put information on it. The troubles for you could be big if they take money from the victims. 
2. A strong DDoS attack can affect your servers, bringing them down. And keep them like this, under attack, for a long time. In practice, an attack can last even weeks. Losing control can affect your clients. Users won’t be able to access and use your services or buy products during the DNS attack. You can lose money and get negative feedback from clients. You can even permanently lose them.   

Anybody could be threatened by DNS attacks, even the big companies. Wikipedia, BBC, Blizzard, and many more have suffered different types of attacks, check here. Nobody is safe, and the news will just keep coming. 

Most common DNS Attack Types

Here are 5 of the most popular DNS attacks that you should be aware of. It is important to not neglect such threats and take measures for prevention.

DDoS Amplification

A DNS attack type like this is the one that you will see a lot on the media. With big headlines and big numbers. There are many types, but most often, the amplification attacks exploit the simple UDP protocol. Take it as the weakest link in the puzzle. It doesn’t use verification, and here comes the problem. The goal is to significantly increase, amplify, traffic. The hackers send a small DNS query and demand not just the IP but also extra information, so the answer is more significant. It could be even 10 times larger! The extra trick is that they can modify the request, so the answer goes to the target. That way, the target can get bombarded with many requests that it didn’t want and to experience downtime. 

How to mitigate it? You will need a large network of servers (DNS), like an Anycast network. If the capacity is enough, the traffic can be filtered without crippling the network. 

Additional measures that you could take are to set a limit to the server, to just listen on only 127.0.0.1 (the localhost). You can, of course, disable the UDP altogether if you don’t use it. 

And the third measure is to use a firewall for port 11211 and allowing server access, limited to just whitelisted IPs.  

DNS Cache Poisoning

This DNS problem focuses on DNS resolvers. Each of them has a cache memory, where it holds information for domains for a certain amount of time. The Resolvers have a copy of the DNS records and keep them the time that TTL (time to live) indicates. The attacker alters the DNS records and redirects the traffic to where he or she wants (another server). There could be a fake copy of your websites where unaware people will register and give their personal data. This is very common with fake spoofing emails. When the victim clicks on the link, malicious software can then modify the records in the DNS resolver. 

You can set limits to the queries to just a specific domain. Also, you can just store the records for a particular domain and no others. Use blacklists to limit. 

The best tool to prevent such a thread is DNSSEC. If a Recursive server was poisoned, it wouldn’t continue the query, and then the user will be safe. 

DNS Tunneling

DNS Tunneling is a DNS attack type that tries to take different important data through DNS without been detected. A tunnel that you don’t see, but criminals use. It is masked as a DNS query but takes hidden data. A sensitive data can go out unnoticed, and that could cost you dearly. 

Your DNS service must have a DNS Protection that acts as an intelligent firewall. But in case you don’t have, you can set up your firewall following the steps: 

You will need to have a firewall and add an access rule to block all the unwanted traffic right away. The second step is to make a protocol object in your firewall. You will need to find “Select Protocols”, choose DNS, and there should be “DNS tunnel”. Press it and save.

Create, in the end, an application rule. Again from the settings of the firewall, You will need to specify the trusted connection and then the protocol – “DNS-Tunneling”. 

DNS Flood Attack

DNS Flood is a simple and very effective attack. The idea is to send traffic from one or many devices to the targeted server. Push with substantial traffic until it drops. In a way, to flood it with information and submerge it until it drowns. If it is a single source, it is easier to manage, but it can be a huge network of bots that could be tricky to handle.

Flood Attack: Prevention and Protection

The protection exists! It is simple, again DDoS Protected servers. It will have a filtering of dangerous traffic. Also, have an Anycast network with a significant amount of servers that will provide excellent load balancing. Currently, we have 49, that will be a good number. And traffic monitor for showing on time any threads and reacting to the traffic will help. 

What is Web monitoring?

Distributed Reflection Denial of Service (DRDoS)

A slightly different type from the DDoS attack we just saw. In this case, not the direct queries, but the answers to them will go to the victim. This is the reflection. 

The cybercriminals will send DNS queries, but the IP of the source will be changed. Servers will respond and will send all that traffic to the target (The modified IP). The traffic can be overwhelming and flood the target, eventually stopping it. A Smurf attack is a popular DNS attack of that type. Sounds cute, but it isn’t. 

The solution again is the same as the one for the DNS Flood type of attack. Get DNS Protected servers. With a proper DNS plan, you will save yourself a lot of troubles. They will have monitoring of the traffic, filters for removing the unwanted requests, a load balancer for heavy traffic, and even more extras for smooth DNS experience. 

How to prevent DNS attacks?

Here are some tips that are going to help you prevent, detect, and mitigate a DNS attack.

• Up-to-date DNS software: It is important to use the latest DNS software that contains the latest patches installed. 
• Multi-factor authentication (MFA): It is crucial to implement MFA for all available accounts which have access to the DNS infrastructure of your organization. 
• Domain Name System Security Extensions (DNSSEC): It ensures the safety of your DNS by utilizing digital signatures based on public key cryptography. That way, DNSSEC adds a very useful extra layer of security to your organization’s DNS.
• Reliable DNS infrastructure: It is the foundation of a safe and protected environment for your organization’s online presence. Anycast DNS network is a must if you receive a lot of DNS requests. However, it will balance the load of an incoming threat. 
• DDoS protected DNS: This service is specifically designed to mitigate one of the most harmful cyber threats – DDoS attacks.
• Constant Monitoring: Logging and monitoring outbound and inbound DNS queries and response data can help significantly in detecting abnormal behaviors.
• Keep a private DNS resolver: Restricting the DNS resolver to only users on your network can minimize the risk of malicious external usage. That way, you prevent its DNS cache from being poisoned by cybercriminals.

Motivation behind DNS attacks

One of the most common reasons behind the DNS attack is unfair competitor behavior. Attacking the competition illegally so that it can suffer downtime and all the consequences of it. But there are more:

• Extortion. Do you know how ransomware is getting popular? There is also DNS attack ransomware, where the cybercriminals are using DDoS attacks to target a server. The server can’t respond to regular connections already, and the attackers demand a ransom to stop the attack. The cryptocurrency has facilitated the ransomware process a lot.
• Revenge. The reason behind the attack could be an act of personal revenge against a company, a supplier, or an individual. For example, it is not uncommon that an ex-employee tries to disturb the services of the previous employer.
• DDoS-for-hire. On the Dark Web, the side of the web that you can’t see in Google, there are all kinds of illegal services that you can hire. People hire DDoS DNS attacks to target their competitors. Bringing down their services during important periods. The attack can lead to serious losses in sales for the victim.
• Cover attack. You can imagine the DNS attack as a smoke grenade. Its purpose could be just a distraction. It is taking the attention towards fixing the DNS traffic while another attack is being conducted or malicious software is installed behind the scene.
• Notoriety. Some people want to be famous, even with their bad deeds. Getting some attention for a successful attack could be enough for some hackers. 
• Personal challenge. There are smart people who just want to test their knowledge. Such a person might perform an attack, with the only idea to see if he or she can do it.
• Cyberwarfare. Some countries use DNS attacks to target other countries, military groups, separatists, opposition, and even media sites sometimes. The goal is to silence or disrupt the communication of the targeted organization entirely.
• Gamers’ wars. Gamers are very connected with technology. They use DNS attacks to damage the score of their competitors so that they can rise above them. Also, they use it to attack particular competitions and change the final results.
• Hacktivism. Non-governmental organizations and individuals who want to make a point often use such tools to make a noise about their cause. Freedom of speech and ecological causes are common. It could attract media attention, start an international debate and stop the services of the targeted organization. 

Consequences of DNS Attacks

Becoming a target of a DNS attack can have a severe negative impact. Let’s examine the most common consequences:

• Data Breaches: One of the most serious consequences of DNS attacks is the potential for data breaches. When attackers successfully manipulate DNS records, they can gain unauthorized access to sensitive information. That means putting personal and financial data at risk, leading to identity theft, financial losses, and reputational damage.
• Business Disruption: Downtime resulting from attacks can have catastrophic effects on businesses. Whether it’s an e-commerce website unable to process transactions or a critical online service experiencing disruptions, the financial damage can be severe. Beyond obvious financial losses, prolonged downtime can have a negative impact on customer trust and loyalty.
• Reputation Damage: DNS attacks not only affect the proper functionality of digital services but can also tear apart an organization’s reputation. Customers, partners, and stakeholders may lose trust in a business’s ability to protect sensitive information, leading to long-term consequences for brand image and market position.

Common Targets of DNS Attacks

Understanding the potential victims of DNS attacks is crucial for implementing robust cybersecurity measures. The following examples are often targeted:

• Enterprises and Organizations: Large corporations and organizations are often targets due to the vast amount of sensitive data they store. DNS attacks can compromise data integrity, leading to financial losses and reputational damage.
• Internet Service Providers (ISPs): ISPs play a key role in managing and directing internet traffic. Attacks on their DNS infrastructure can result in widespread service disruptions, affecting countless users.
• Government Agencies: Governments keep vast amounts of confidential information critical to national security. DNS attacks on government agencies can lead to data breaches and compromise sensitive data.
• E-commerce Platforms: Online retailers are also an attractive target for attacks as they handle numerous financial transactions and store customer details. A successful attack can disrupt services, leading to financial losses and crashing customer trust.
• Critical Infrastructure: Industries such as energy, transportation, and healthcare rely on interconnected systems. DNS attacks on such critical infrastructure can impact public safety and fundamental services.
• Financial Institutions: Financial institutions dealing with sensitive transactions and client data are also often targets of attacks. A successful assault on their DNS can result in phishing attacks, leading to identity theft or fraudulent transactions, causing extreme financial damage.

Conclusion

It is really important to know about DNS attack types and how to protect us from them so your business experiences fewer shocks. Smooth sail for your business. You don’t want to suffer brand damages, lawsuits that cost millions of dollars or losing clients because of downtime. To avoid them we recommend you take a look of our DDoS protected DNS service, and test our FREE 30-day trial!

 Prevent DDoS attacks!

The post 5 DNS Attacks that could affect you appeared first on ClouDNS Blog.

What is a DNS flood attack?

A DNS flood attack is a type of Distributed Denial of Service (DDoS) attack. It targets the DNS server, which is crucial for translating domain names (like www.example.com) into IP addresses that computers use to communicate. The attack floods the DNS server with an overwhelming number of requests, causing legitimate traffic to be delayed or completely blocked, effectively taking the service offline.

How does a DNS flood attack work?

Imagine a small post office suddenly receiving millions of letters, most with incorrect return addresses. A DNS flood attack operates similarly. Attackers leverage a network of compromised devices, known as a botnet, to send a deluge of DNS requests to a target server. These requests are often disguised with fake IP addresses, adding confusion and preventing easy filtering. The server, inundated by this tsunami of requests, struggles to respond, leading to legitimate requests being ignored or delayed – effectively disrupting normal web services. 

Let’s break down the process into steps:

1. Volume of traffic: The attacker sends a massive amount of DNS requests to the target server, often using a network of compromised computers (botnets).
2. Spoofing IP addresses: These requests often have fake return addresses, making it hard for the server to distinguish between legitimate and illegitimate traffic.
3. Server overload: The DNS server becomes overwhelmed, trying to process each request, leading to slowed down services or a total shutdown.
4. Secondary effects: The attack can also impact other services that rely on the DNS server, creating a ripple effect of disruption.

Why is it dangerous?

The danger of DNS flood attack cannot be overstated. They are more than just an inconvenience; they pose a significant threat to online operations. Firstly, they can cause major disruptions to essential services, crippling websites and online platforms. This disruption can have a cascading effect, impacting not only the targeted site but also any service that relies on it. The financial implications are equally severe, especially for businesses that depend on online transactions or services. Beyond the immediate financial losses, these attacks can inflict long-term damage to a company’s reputation, shaking customer confidence and trust. Moreover, while the focus is on mitigating the attack, other security vulnerabilities might be overlooked, leaving the door open for further exploits.

How to recognize a DNS flood attack?

Identifying a DNS flood attack primarily involves monitoring for an abnormal surge in DNS traffic. This is where tools like ClouDNS Free DNS tool come into play. This innovative tool enables users to inspect DNS records for specific hosts and analyze the speed and volume of DNS queries. Users can conduct a thorough audit of their DNS traffic, a crucial step in early detection. The tool’s user-friendly interface and comprehensive functionality, including compatibility with major DNS resolvers like Cloudflare, make it an invaluable resource in a cybersecurity toolkit.

DNS flood attack mitigation

To defend against DNS flood attacks, consider the following strategies:

DNSSEC (Domain Name System Security Extensions):

DNSSEC adds an extra layer of security by verifying the authenticity of DNS responses. This helps ensure that the data hasn’t been altered, making it harder for attackers to exploit the DNS system.

DDoS Protection Service:

DDoS Protection services specialize in distinguishing and mitigating abnormal traffic patterns characteristic of DDoS attacks. They can redirect malicious traffic, keeping your DNS server operational.

DNS Monitoring:

Regularly monitoring DNS traffic for unusual patterns helps in early detection of potential attacks, allowing for swift action before significant disruption occurs.

Enabling DNS Caching:

DNS caching reduces the load on servers by storing responses locally. During an attack, cached data can still be served, maintaining service availability for some users.

Secondary DNS:

A Secondary DNS provides redundancy. If your primary server is overwhelmed, the secondary server can maintain service availability, minimizing downtime.

DoT (DNS over TLS) and DoH (DNS over HTTPS):

Implementing DoT and DoH encrypts DNS queries, enhancing security. They help differentiate legitimate traffic from malicious queries, as most attack traffic doesn’t use these secure channels.

Conclusion

In summary, effectively mitigating DNS flood attacks involves a blend of strategic defenses and proactive monitoring. By adopting a range of protective measures and staying vigilant, organizations can safeguard their online presence against these disruptive threats. Remember, a robust defense is essential in maintaining the integrity and reliability of your digital services in today’s interconnected world.

The post DNS flood attack explained in details appeared first on ClouDNS Blog.