What is DDoS denial of service?
What everyone needs to know about DDoS
DDoS stands for Distributed Denial of Service. A malicious hacker uses a DDoS attack to make a computer resource (i.e. – website, application, e-mail, voicemail, network) stop responding to legitimate users. The malicious hacker does this by commanding a fleet of remotely-controlled computers to send a flood of network traffic to the target. The target becomes so busy dealing with the attacker’s requests that it doesn’t have time to respond to legitimate users’ requests. That can cause the target system to stop responding, resulting in long delays and outages.
What is a distributed attack?
One DDoSer can do a lot of damage. These denial of service attacks are called distributed because they come from many computers at once. A DDoSer controls a large number of computers that have been infected by a Trojan virus. The virus is a small application that allows remote command-and-control capabilities of the computer without the user’s knowledge.
What is a zombie and a botnet?
The virus-infected computers are called zombies – because they do whatever the DDoSer commands them to do. A large group of zombie computers is called a robot network, or botnet.
Your computer could be part of a botnet without your knowledge. You might not notice any difference, or you might notice your computer is not as fast as it used to be. That’s because it may be busy participating in a DDoS attack at the same time you are using it. Or, you might find out that your computer is infected when your Internet service provider (ISP) drops your service because your computer is sending an unusually high number of network requests.
What is a DDoS command-and-control server?
Zombie computers in a botnet receive instructions from a command and control server, which is an infected web server. DDoSers who have access to a command and control (C&C or CC) server can recruit the botnet to launch DDoS attacks. Prolexic has identified more than 4,000 command-and-control servers and more than 10 million zombies worldwide. We track them and notify law enforcement to disable them when possible.
Many types of DDoS attacks
There are many types of DDoS attacks. They target different network components – routers, appliances, firewalls, applications, ISPs, even data centers – in different ways. There is no easy way to prevent DDoS attacks, but Prolexic has a proven DDoS protection approach that works to minimize the damage and let your system keep working during an attack.
DDoS attackers use a variety of DDoS attack methods. The malicious hacker group Anonymous, for example, started with a tool that could launch Layer 7 DDoS attacks and Layer 3 DDoS attacks from any computer. These attacks had a common attack signature – that is, common code. As a result, the attacks could be detected and mitigated (stopped) fairly easily.
It’s a game of cat and mouse. The cat learns about what the mouse is doing, so the mouse changes tactics to avoid getting caught. DDoSers got smarter and started randomizing their attack signatures and encrypting their code. Some even started using browsers to visit a web page and feed harmful code to a web application on the site.
Although application-layer DDoS attacks are more difficult to recognize, DDoS mitigation experts in our Security Operations Center (SOC) know what to look for – and we are always looking. Our anti-DDoS experts monitor and analyze these attacks all the time– day and night – and block the DDoS attacks that target our clients.
What are application layer 7 DDoS attacks?
Application layer 7 (L7) attacks may not create such high volumes of network traffic, but they can harm your website in a more devastating way. They might activate some aspect of a web application, such as posting different user names and passwords, or targeting a shopping cart or search engine.
Many of the high profile e-Commerce outages are the result of Layer 7 application attacks. The biggest issue is that Layer 7 attacks change and randomize very fast. Anything a visitor can access an attacker can too – and it looks the same to an IT administrator.
Know this – automated mitigation appliances, firewalls, ISPs, and cloud providers simply cannot mitigate Layer 7 attacks. But Prolexic can because our technicians monitor and analyze the attack while it’s happening – and have the tools and expertise to block all Layer 7 attacks.
Learn more about DDoS attacks and DDoS protection from Prolexic.
Ready to learn more?
Learn about why Prolexic offers the best DDoS detection and protection services.
Subscribe to DDoS Dispatch, our DDoS protection newsletter, and get on our list to receive alerts when we release new DDoS attack reports, threat advisories, and more.
Visit the Prolexic Knowledge Center for detailed customer case studies, attack reports and more.
Alliant Credit Union
Prolexic DDoS protection keeps more than 50,000 daily users onlineDOWNLOAD CASE STUDY >>
Fragrance and Beauty Products Retailer
A DDoS attack takes down this popular site for 24 hours. Prolexic restores in 5 minutes.DOWNLOAD CASE STUDY >>
Leading Online Jewelry Retailer
A DDoS attack took down the site of a premier jewelry retailer for nearly three days.DOWNLOAD CASE STUDY >>
Online Options Trading
Financial services firm avoids extortion attempt. Prolexic keeps web site up during vicious Layer 7 attack.DOWNLOAD CASE STUDY >>
When others couldn't mitigate the latest DDoS attack, a "daily deal" web site called Prolexic: problem solved in 2 hours.DOWNLOAD CASE STUDY >>
A Leading Content Rating Organization
A 9 million packets per second DDoS attack brings down web site before Prolexic steps in.DOWNLOAD CASE STUDY >>
Spa and Wellness Firm
Prolexic quickly stops a combination Layer 4 and 7 DDoS attack after a host's mitigation capabilities falls short.DOWNLOAD CASE STUDY >>
Prolexic mitigates GET flood in minutes for new client after Sunday night emergency call.DOWNLOAD CASE STUDY >>
Web site building and hosting services firm
Prolexic mitigates Layer 4 UDP flood peaking at 6.2 Gbps. Protects 6 million Yolasites.DOWNLOAD CASE STUDY >>
Online Movie Subscription Service
After seeing all traffic route to Prolexic, hackers pull the plug on DDoS attack.DOWNLOAD CASE STUDY >>
IPG Holdings Limited
Prolexic mitigates Layer 7 GET floods targeting payment processing platform.DOWNLOAD CASE STUDY >>
Prolexic mitigates politically motivated attacks against web hosting company's clients.DOWNLOAD CASE STUDY >>
Financial Services Firm Global eSolutions
Prolexic mitigates Layer 3, 4 and 7 attacks against Forex trading platform.DOWNLOAD CASE STUDY >>
Krebs on Security
Prolexic fends off Pandora DNS amplification attacks for popular cyber security blog.DOWNLOAD CASE STUDY >>
e-Commerce Provider of Printed Promotion Items
Prolexic mitigates two-week Layer 7 DDoS attack campaign.DOWNLOAD CASE STUDY >>
Global Blogging Site
Prolexic protects freedom of speech for 30 million users targeted by six-month political DDoS campaign.DOWNLOAD CASE STUDY >>
Online Credit Card Site
Prolexic mitigates Layer 4 DDoS attacks against Ixaris site, EntroPay.com.DOWNLOAD CASE STUDY >>
e-Commerce Web Site
Prolexic mitigates 25-40 Gbps Layer 3 DDoS attacks against online auto parts retailer.DOWNLOAD CASE STUDY >>
Timepieces e-Commerce Site
Prolexic keeps World of Watches ticking after DDoS attack flood site.DOWNLOAD CASE STUDY >>
Prolexic mitigates 16-hour Layer 7 DDoS attack on software distribution site.DOWNLOAD CASE STUDY >>
Henyep Capital Markets
Prolexic keeps Henyep accessible and trading through multiple SYN, GET and ICMP flood attacks.DOWNLOAD CASE STUDY >>
Australia’s #1 Job Search Website
Prolexic keeps Seek.com.au online and incident-free for millions of job seekers.DOWNLOAD CASE STUDY >>
e-Commerce Hosting Provider for Top Tier Sites
Prolexic keeps Americaneagle.com and its customers generating revenueDOWNLOAD CASE STUDY >>
Customer ROI requires online accessibility and reliability
Prolexic ensures Clickpoint! Media's online services are available and incident-freeDOWNLOAD CASE STUDY >>
University Federal Credit Union
Prolexic's mitigation services now protect credit union with US$1.6 Billion in assetsDOWNLOAD CASE STUDY >>
Prolexic mitigates 70 Gbps SYN flood DDoS attack for popular ink retailerDOWNLOAD CASE STUDY >>
Arab National Bank
Builds strong DDoS defense to serve online banking customers and e-trade siteDOWNLOAD CASE STUDY >>
OnCourse Systems for Education
Prolexic succeeded where two other mitigation firms failedDOWNLOAD CASE STUDY >>
Q3 2014 State of the Internet - Security Report
Thriving criminal industry taps into Internet devices, spreads easy-to-use toolsLEARN MORE >>
Threat: SSDP Reflection DDoS Attacks
Misconfigured UPnP devices pose DDoS threatLEARN MORE >>
Big Data – Your Secret Weapon in the War Against Cyber Crime
Free webcast featuring IDC 58:07 minutesLEARN MORE >>
Web Vulnerabilities: The foundation of sophisticated DDoS campaigns
Protect your servers and help stop DDoS attacksLEARN MORE >>
Gatepoint Research report: Beyond the Firewall: Protection & Performance
New technologies demand new, flexible approaches to web securityLEARN MORE >>
Can You Afford a Web Application Layer Attack?
Why protecting your customers’ personal information is good businessLEARN MORE >>