Goodbye 3 5.2 Denial Of Service Tool

Updated: October 30, 2020

IPsec-Tools Multiple Remote Denial Of Service Vulnerabilities. Mac OS X 10.5.4 Apple Mac OS X 10.5.3 Apple Mac OS X 10.5.2 Apple Mac OS X 10.5.1 Apple Mac OS X. SC-5 (3)(a) Employs Assignment: organization-defined monitoring tools to detect indicators of denial of service attacks against the information system; and: SC-5 (3)(b) Monitors Assignment: organization-defined information system resources to determine if sufficient resources exist to prevent effective denial of service attacks.

Distributed Denial of Service (DDoS) attacks are now everyday occurrences. Whether you’re a small non-profit or a huge multinational conglomerate, your online services—email, websites, anything that faces the internet—can be slowed or completely stopped by a DDoS attack. Moreover, DDoS attacks are sometimes used to distract your cybersecurity operations while other criminal activity, such as data theft or network infiltration, is underway.

DDoS are Attacks Getting Bigger, More Frequent

The first known Distributed Denial of Service attack occurred in 1996 when Panix, now one of the oldest internet service providers, was knocked offline for several days by a SYN flood, a technique that has become a classic DDoS attack. Over the next few years DDoS attacks became common and Cisco predicts that the total number of DDoS attacks will double from the 7.9 million seen in 2018 to something over 15 million by 2023.

Total DDoS Attacks

Figure 1. Cisco’s analysis of DDoS total attacks history and predictions.

But it’s not just the number of DDoS attacks that are increasing. The bad guys are creating ever bigger botnets – the armies of hacked devices that are used to generate DDoS traffic. As the botnets get bigger, the scale of DDoS attacks is also increasing. A Distributed Denial of Service attack of one gigabit per second is enough to knock most organizations off the internet but we’re now seeing peak attack sizes in excess of one terabit per second generated by hundreds of thousands or even millions of suborned devices. For more background about what’s technically involved in a Distributed Denial of Service attack, see our post What is a DDoS Attack?, and our video WHO, WHAT, WHY, WHERE of DDoS Attacks.

The Cost of DDoS Attacks

Given that IT services downtime costs companies anywhere from $300,000 to over $1,000,000 per hour, you can see that the financial hit from even a short DDoS attack could seriously damage your bottom line. To understand what impact a Distributed Denial of Service attack could have on your organization and your cybersecurity planning, please see our white paper How to Analyze the Business Impact of DDoS Attacks.

The Top-Five Most Famous DDoS Attacks (for Now)

To give you insight into what these attacks are like “in the wild,” we’re going to take a look at some of the most notable DDoS attacks to date. Our choices include some DDoS attacks that are famous for their sheer scale while our others are because of their impact and consequences.

1. The Google Attack, 2017

On October 16, 2020, Google’s Threat Analysis Group (TAG) posted a blog update discussing how the threats and threat actors are changing their tactics due to the 2020 U.S. election. At the end of the post, the company snuck in a note:

In 2017, our Security Reliability Engineering team measured a record-breaking UDP amplification attack sourced out of several Chinese ISPs (ASNs 4134, 4837, 58453, and 9394), which remains the largest bandwidth attack of which we are aware.

Launched from three Chinese ISPs, the attack on thousands of Google’s IP addresses lasted for six months and peaked at a breath-taking 2.5 Tbps. Damian Menscher, a Security Reliability Engineer at Google, wrote:

The attacker used several networks to spoof 167 Mpps (millions of packets per second) to 180,000 exposed CLDAP, DNS, and SMTP servers, which would then send large responses to us. This demonstrates the volumes a well-resourced attacker can achieve. This was four times larger than the record-breaking 623 Gbps attack from the Mirai botnet a year earlier.

2. The AWS DDoS Attack in 2020

Amazon Web Services, the 800-pound gorilla of everything cloud computing, was hit by a gigantic DDoS attack in February 2020. This was the most extreme recent DDoS attack ever and it targeted an unidentified AWS customer using a technique called Connectionless Lightweight Directory Access Protocol (CLDAP) Reflection. This technique relies on vulnerable third-party CLDAP servers and amplifies the amount of data sent to the victim’s IP address by 56 to 70 times. The attack lasted for three days and peaked at an astounding 2.3 terabytes per second.

Why the AWS Attack Matters

While the disruption caused by the AWS DDoS Attack was far less severe than it could have been, the sheer scale of the attack and the implications for AWS hosting customers potentially losing revenue and suffering brand damage are significant.

3. The Mirai Krebs and OVH DDoS Attacks in 2016

On September 20, 2016, the blog of cybersecurity expert Brian Krebs was assaulted by a DDoS attack in excess of 620 Gbps, which at the time, was the largest attack ever seen. Krebs’ site had been attacked before. Krebs had recorded 269 DDoS attacks since July 2012, but this attack was almost three times bigger than anything his site or, for that matter, the internet had seen before.

The source of the attack was the Mirai botnet, which, at its peak later that year, consisted of more than 600,000 compromised Internet of Things (IoT) devices such as IP cameras, home routers, and video players. The Mirai botnet had been discovered in August that same year but the attack on Krebs’ blog was its first big outing.

The next Mirai botnet attack on September 19 targeted one of the largest European hosting providers, OVH, which hosts roughly 18 million applications for over one million clients. This attack was on a single undisclosed OVH customer and driven by an estimated 145,000 bots, generating a traffic load of up to 1.1 terabits per second, and lasted about seven days. But OVH was not to be the last Mirai botnet victim in 2016 … please see the next section.

Why the Mirai Krebs and OVH Attacks Matter

The first known Distributed Denial of Service attack occurred in 1996 when Panix, now one of the oldest internet service providers, was knocked offline for several days by a SYN flood, a technique that has become a classic DDoS attack. Over the next few years DDoS attacks became common and Cisco predicts that the total number of DDoS attacks will double from the 7.9 million seen in 2018 to something over 15 million by 2023.

Total DDoS Attacks

Figure 1. Cisco’s analysis of DDoS total attacks history and predictions.

But it’s not just the number of DDoS attacks that are increasing. The bad guys are creating ever bigger botnets – the armies of hacked devices that are used to generate DDoS traffic. As the botnets get bigger, the scale of DDoS attacks is also increasing. A Distributed Denial of Service attack of one gigabit per second is enough to knock most organizations off the internet but we’re now seeing peak attack sizes in excess of one terabit per second generated by hundreds of thousands or even millions of suborned devices. For more background about what’s technically involved in a Distributed Denial of Service attack, see our post What is a DDoS Attack?, and our video WHO, WHAT, WHY, WHERE of DDoS Attacks.

The Cost of DDoS Attacks

Given that IT services downtime costs companies anywhere from $300,000 to over $1,000,000 per hour, you can see that the financial hit from even a short DDoS attack could seriously damage your bottom line. To understand what impact a Distributed Denial of Service attack could have on your organization and your cybersecurity planning, please see our white paper How to Analyze the Business Impact of DDoS Attacks.

The Top-Five Most Famous DDoS Attacks (for Now)

To give you insight into what these attacks are like “in the wild,” we’re going to take a look at some of the most notable DDoS attacks to date. Our choices include some DDoS attacks that are famous for their sheer scale while our others are because of their impact and consequences.

1. The Google Attack, 2017

On October 16, 2020, Google’s Threat Analysis Group (TAG) posted a blog update discussing how the threats and threat actors are changing their tactics due to the 2020 U.S. election. At the end of the post, the company snuck in a note:

In 2017, our Security Reliability Engineering team measured a record-breaking UDP amplification attack sourced out of several Chinese ISPs (ASNs 4134, 4837, 58453, and 9394), which remains the largest bandwidth attack of which we are aware.

Launched from three Chinese ISPs, the attack on thousands of Google’s IP addresses lasted for six months and peaked at a breath-taking 2.5 Tbps. Damian Menscher, a Security Reliability Engineer at Google, wrote:

The attacker used several networks to spoof 167 Mpps (millions of packets per second) to 180,000 exposed CLDAP, DNS, and SMTP servers, which would then send large responses to us. This demonstrates the volumes a well-resourced attacker can achieve. This was four times larger than the record-breaking 623 Gbps attack from the Mirai botnet a year earlier.

2. The AWS DDoS Attack in 2020

Amazon Web Services, the 800-pound gorilla of everything cloud computing, was hit by a gigantic DDoS attack in February 2020. This was the most extreme recent DDoS attack ever and it targeted an unidentified AWS customer using a technique called Connectionless Lightweight Directory Access Protocol (CLDAP) Reflection. This technique relies on vulnerable third-party CLDAP servers and amplifies the amount of data sent to the victim’s IP address by 56 to 70 times. The attack lasted for three days and peaked at an astounding 2.3 terabytes per second.

Why the AWS Attack Matters

While the disruption caused by the AWS DDoS Attack was far less severe than it could have been, the sheer scale of the attack and the implications for AWS hosting customers potentially losing revenue and suffering brand damage are significant.

3. The Mirai Krebs and OVH DDoS Attacks in 2016

On September 20, 2016, the blog of cybersecurity expert Brian Krebs was assaulted by a DDoS attack in excess of 620 Gbps, which at the time, was the largest attack ever seen. Krebs’ site had been attacked before. Krebs had recorded 269 DDoS attacks since July 2012, but this attack was almost three times bigger than anything his site or, for that matter, the internet had seen before.

The source of the attack was the Mirai botnet, which, at its peak later that year, consisted of more than 600,000 compromised Internet of Things (IoT) devices such as IP cameras, home routers, and video players. The Mirai botnet had been discovered in August that same year but the attack on Krebs’ blog was its first big outing.

The next Mirai botnet attack on September 19 targeted one of the largest European hosting providers, OVH, which hosts roughly 18 million applications for over one million clients. This attack was on a single undisclosed OVH customer and driven by an estimated 145,000 bots, generating a traffic load of up to 1.1 terabits per second, and lasted about seven days. But OVH was not to be the last Mirai botnet victim in 2016 … please see the next section.

Why the Mirai Krebs and OVH Attacks Matter

The Mirai botnet was a significant step up in how powerful a DDoS attack could be. The size and sophistication of the Mirai network was unprecedented as was the scale of the attacks and their focus.

Video: What is Mirai and How do You Protect Yourself Against it?

4. The Mirai Dyn DDoS Attack in 2016

Before we discuss the third notable Mirai botnet DDoS attack of 2016, there’s one related event that should be mentioned. On September 30, someone claiming to be the author of the Mirai software released the source code on various hacker forums and the Mirai DDoS platform has been replicated and mutated scores of times since.

Figure 2. A map of internet outages in Europe and North America caused by the Dyn cyberattack October 2, 2016 / Source: DownDetector (CC BY-SA)

On October 21, 2016, Dyn, a major Domain Name Service (DNS) provider, was assaulted by a one terabit per second traffic flood that then became the new record for a DDoS attack. There’s some evidence that the DDoS attack may have actually achieved a rate of 1.5 terabits per second. The traffic tsunami knocked Dyn’s services offline rendering a number of high-profile websites including GitHub, HBO, Twitter, Reddit, PayPal, Netflix, and Airbnb, inaccessible. Kyle York, Dyn’s chief strategy officer, reported, “We observed 10s of millions of discrete IP addresses associated with the Mirai botnet that were part of the attack.”

Why the Mirai Dyn Attack Matters

Mirai supports complex, multi-vector attacks that make mitigation difficult. Even though the Mirai botnet was responsible for the biggest assaults up to that time, the most notable thing about the 2016 Mirai attacks was the release of the Mirai source code enabling anyone with modest information technology skills to create a botnet and mount a Distributed Denial of Service attack without much effort.

5. The Six Banks DDoS Attack in 2012

On March 12, 2012, six U.S. banks were targeted by a wave of DDoS attacks—Bank of America, JPMorgan Chase, U.S. Bank, Citigroup, Wells Fargo, and PNC Bank. The attacks were carried out by hundreds of hijacked servers from a botnet called Brobot with each attack generating over 60 gigabits of DDoS attack traffic per second.

At the time, these attacks were unique in their persistence. Rather than trying to execute one attack and then backing down, the perpetrators barraged their targets with a multitude of attack methods in order to find one that worked. So, even if a bank was equipped to deal with a few types of DDoS attacks, they were helpless against other types of attack.

Why the Six Banks Attack Matters

The most remarkable aspect of the bank attacks in 2012 was that the attacks were, allegedly, carried out by the Izz ad-Din al-Qassam Brigades, the military wing of the Palestinian Hamas organization. Moreover, the attacks had a huge impact on the affected banks in terms of revenue, mitigation expenses, customer service issues, and the banks’ branding and image.

Actionable DDoS weapons intelligence enables a proactive approach to DDoS protection

Learn how DDoS weapons intelligence enables a proactive approach to DDoS protection by creating blacklists based on current and accurate feeds of IP addresses of DDoS botnets and available vulnerable servers commonly used for DDoS attacks.

Other Notable Distributed Denial of Service Attacks

6. The GitHub Attack in 2018

On Feb. 28, 2018, GitHub—a platform for software developers—was hit with a DDoS attack that clocked in at 1.35 terabits per second and lasted for roughly 20 minutes. According to GitHub, the traffic was traced back to “over a thousand different autonomous systems (ASNs) across tens of thousands of unique endpoints.”

The following chart shows just how much of a difference there was between normal traffic levels and those of the attack.

Figure 3. Chart of the February 2018 DDoS attack on GitHub. Source: Wired

Even though GitHub was well prepared for a DDoS attack their defenses were overwhelmed—they simply had no way of knowing that an attack of this scale would be launched. As GitHub explained in the company’s incident report: “Over the past year we have deployed additional transit to our facilities. We’ve more than doubled our transit capacity during that time, which has allowed us to withstand certain volumetric attacks without impact to users … Even still, attacks like this sometimes require the help of partners with larger transit networks to provide blocking and filtering.”

Why the GitHub Attack Matters

The GitHub DDoS attack was notable for its scale and the fact that the attack was staged by exploiting a standard command of Memcached, a database caching system for speeding up websites and networks. The Memcached DDoS attack technique is particularly effective as it provides an amplification factor – the ratio of the attacker’s request size to the amount of DDoS attack traffic generated – of up to a staggering 51,200 times.

7. Occupy Central, Hong Kong DDoS Attack in 2014

The multi-day PopVote DDoS attack was carried out in 2014 and targeted the Hong Kong-based grassroots movement known as Occupy Central, which was campaigning for a more democratic voting system.

In response to their activities, attackers sent large amounts of traffic to three of Occupy Central’s web hosting services, as well as two independent sites, PopVote, an online mock election site, and Apple Daily, a news site, neither of which were owned by Occupy Central but openly supported its cause. Presumably, those responsible were reacting to Occupy Central’s pro-democracy message.

The attack barraged the Occupy Central servers with packets disguised as legitimate traffic and was executed using not one, not two, but five botnets and resulted in peak traffic levels of 500 gigabits per second.

Why the Occupy Central Attack Matters

It was reported that the attackers were probably connected to the Chinese government, there has never been conclusive proof and, perversely, the attack could have been intended to make the Chinese government look bad. The attack may have also provided cover for hackers who managed to extract Occupy Central staff details from a database to mount an extensive subsequent phishing campaign.

8. The CloudFlare DDoS Attack in 2014

In 2014, CloudFlare, a cybersecurity provider and content delivery network, was slammed by a DDoS attack estimated at approximately 400 gigabits per second of traffic. The attack, directed at a single CloudFlare customer and targeted on servers in Europe, was launched using a vulnerability in the Network Time Protocol (NTP) protocol which is used to ensure computer clocks are accurate. Even though the attack was directed at just one of CloudFlare’s customers, it was so powerful it significantly degraded CloudFlare’s own network.

Why the CloudFlare Attack Matters

This attack illustrates a technique where attackers use spoofed source addresses to send fake NTP server responses to the attack target’s servers. This type of attack is known as a “reflection attack,” since the attacker is able to “bounce” bogus requests off of the NTP server while hiding their own address and due to a weakness in the NTP protocol, the amplification factor of the attack can be up to 206 times, making NTP servers a very effective DDoS tool. Shortly after the attack, the U.S. Computer Emergency Readiness team explained NTP amplification attacks are, “especially difficult to block” because “responses are legitimate data coming from valid servers.”

9. The Spamhaus DDoS Attack in 2013

In 2013, a huge DDoS attack was launched against Spamhaus, a nonprofit threat intelligence provider. Although Spamhaus, as an anti-spam organization, was and still is regularly threatened and attacked and had DDoS protection services already in place, this attack—a reflection attack estimated at 300 gigabits of traffic per second—was large enough to knock its website and part of its email services offline.

Why the Spamhaus Attack Matters

The cyberattack was traced to a member of a Dutch company named Cyberbunker, which had apparently targeted Spamhaus after it blacklisted the company for spamming. This illustrates that companies and or rogue employees can mount DDoS attacks with immense brand damaging and serious legal consequences.

DDoS Attack Prevention with A10’s DDoS Protection Solutions

Even though new types of Distributed Denial of Service attacks appear frequently, A10 Thunder® Threat Protection System (TPS) employs advanced defense strategies that protect against all kinds of cyberattacks including new, novel DDoS attacks that could bring down your online and in-house services. Visit A10’s DDoS Protection solution page to learn more.

For additional insight, including the top reflector searches and DDoS research insights performed by attackers, download the complete A10 Networks report, The State of DDoS Weapons.

How A10 Can Help

A10’s Thunder® Threat Protection System (TPS) employs advanced defense strategies that protect against all kinds of DDoS attacks

Feb. 5, 2020

A “denial of service” or DoS attack is used to tie up a website’s resources so that users who need to access the site cannot do so. Many major companies have been the focus of DoS attacks. Because a DoS attack can be easily engineered from nearly any location, finding those responsible can be extremely difficult.

A bit of history: The first DoS attack was done by 13-year-old David Dennis in 1974. Dennis wrote a program using the “external” or “ext” command that forced some computers at a nearby university research lab to power off.

DoS attacks have evolved into the more complex and sophisticated “distributed denial of service” (DDoS) attacks. The biggest attack ever recorded — at that time — targeted code-hosting-service GitHub in 2018. We’ll discuss DDoS attacks in greater detail later in this article.

Attackers include hacktivists (hackers whose activity is aimed at promoting a social or political cause), profit-motivated cybercriminals, and nation states.

Denial of service attacks explained

DoS attacks generally take one of two forms. They either flood web services or crash them.
Flooding attacks

Flooding is the more common form DoS attack. It occurs when the attacked system is overwhelmed by large amounts of traffic that the server is unable to handle. The system eventually stops.
An ICMP flood — also known as a ping flood — is a type of DoS attack that sends spoofed packets of information that hit every computer in a targeted network, taking advantage of misconfigured network devices.

A SYN flood is a variation that exploits a vulnerability in the TCP connection sequence. This is often referred to as the three-way handshake connection with the host and the server. Here’s how it works:

The targeted server receives a request to begin the handshake. But, in a SYN flood, the handshake is never completed. That leaves the connected port as occupied and unavailable to process further requests. Meanwhile, the cybercriminal continues to send more and more requests, overwhelming all open ports and shutting down the server.

Crash attacks

Crash attacks occur less often, when cybercriminals transmit bugs that exploit flaws in the targeted system. The result? The system crashes.

Crash attacks — and flooding attacks — prevent legitimate users from accessing online services such as websites, gaming sites, email, and bank accounts.

How a DoS attack works

Unlike a virus or malware, a DoS attack doesn’t depend on a special program to run. Instead, it takes advantage of an inherent vulnerability in the way computer networks communicate.

Here’s an example. Suppose you wish to visit an e-commerce site in order to shop for a gift. Your computer sends a small packet of information to the website. The packet works as a “hello” – basically, your computer says, “Hi, I’d like to visit you, please let me in.”

When the server receives your computer’s message, it sends a short one back, saying in a sense, “OK, are you real?” Your computer responds — “Yes!” — and communication is established.

The website’s homepage then pops up on your screen, and you can explore the site. Your computer and the server continue communicating as you click links, place orders, and carry out other business.

In a DoS attack, a computer is rigged to send not just one “introduction” to a server, but hundreds or thousands. The server — which cannot tell that the introductions are fake — sends back its usual response, waiting up to a minute in each case to hear a reply. When it gets no reply, the server shuts down the connection, and the computer executing the attack repeats, sending a new batch of fake requests.

DoS attacks mostly affect organizations and how they run in a connected world. For consumers, the attacks hinder their ability to access services and information.

Other types of attacks: DDoS

Distributed denial of service (DDoS) attacks represent the next step in the evolution of DoS attacks as a way of disrupting the Internet. Cybercrimininals began using DDoS attacks around 2000.

Here’s why DDoS attacks have become the weapon of choice for disrupting networks, servers, and websites.

The attacks use large numbers of compromised computers, as well as other electronic devices — such as webcams and smart televisions that make up the ever-increasing Internet of Things — to force the shutdown of the targeted website, server or network.

Security vulnerabilities in Internet-of-Things devices can make them accessible to cybercriminals seeking to anonymously and easily launch DDoS attacks.
In contrast, a DoS attack generally uses a single computer and a single IP address to attack its target, making it easier to defend against.

How to help prevent DoS attacks

If you rely on a website to do business, you probably want to know about DoS attack prevention.

A general rule: The earlier you can identify an attack-in-progress, the quicker you can contain the damage. Here are some things you can do.

Method 1: Get help recognizing attacks

Companies often use technology or anti-DDoS services to help defend themselves. These can help you recognize between legitimate spikes in network traffic and a DDoS attack.

Method 2: Contact your Internet Service provider

If you find your company is under attack, you should notify your Internet Service Provider as soon as possible to determine if your traffic can be rerouted. Having a backup ISP is a good idea, too. Also, consider services that can disperse the massive DDoS traffic among a network of servers. That can help render an attack ineffective.

Goodbye 3 5.2 Denial Of Service Tool Free

Method 3: Investigate black hole routing

Internet service providers can use “black hole routing.” It directs excessive traffic into a null route, sometimes referred to as a black hole. This can help prevent the targeted website or network from crashing. The drawback is that both legitimate and illegitimate traffic is rerouted in the same way.

Method 4: Configure firewalls and routers

Firewalls and routers should be configured to reject bogus traffic. Remember to keep your routers and firewalls updated with the latest security patches.

Method 5: Consider front-end hardware

Application front-end hardware that’s integrated into the network before traffic reaches a server can help analyze and screen data packets. The hardware classifies the data as priority, regular, or dangerous as they enter a system. It can also help block threatening data.

What is a firewall?

A firewall is a barrier protecting a device from dangerous and unwanted communications. Here’s what you need to know.

How to help mitigate against DoS attacks and DDoS attacks

Comprehensive protection against a variety of DDoS threats such as brute force attacks, spoofing, zero-day DDoS attacks and attacks targeting DNS servers.

If you operate on a smaller scale — say, you operate a basic website offering a service — your chances of becoming a victim of a DDoS attack is probably quite low. Even so, taking certain precautions will help protect you against becoming a victim of any type of attack by hackers.

Goodbye 3 5.2 Denial Of Service Tool Making

Here are a few things that can help.

• Keep your security software, operating system, and applications updated. Security updates help patch vulnerabilities which hackers may try to exploit. Consider a trusted security software like Norton Security.
• Consider a router that comes with built-in DDoS protection.
• Look for a website hosting service with an emphasis on security.

Taking simple precautions can make a difference when it comes to your online security. For large organizations, the precautions become far more complex.

Goodbye 3 5.2 Denial Of Service Tool Template

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