What’s the Difference Between DoS Attack vs. DDoS Attack
Cyber-attacks that disrupt network services and bring down websites continue to pose serious threats. DoS Attack vs. DDoS Attack are two common methods used by hackers to overwhelm websites and cause denial of service. While both attack types have the same end goal, there are some key differences between DoS and DDoS attacks in how they are executed and defended against.
A DoS attack involves one computer flooding a target with requests, while a DDoS attack uses multiple computers to bombard the target. Understanding the distinction between these dangerous hacking techniques is critical for implementing effective security measures. This article will compare and contrast DoS and DDoS attacks, analyzing their mechanisms, tools used, impacts, and
Key Takeaways
- A DoS attack involves flooding a target with one computer and one internet connection, while a DDoS attack uses multiple computers and internet connections.
- DDoS attacks are more difficult to mitigate due to the distributed nature of the attack traffic.
- DoS attacks typically use one method to overwhelm the target, whereas DDoS attacks often use multiple attack vectors.
- DDoS attacks are more complex to orchestrate but can be rented as a service, making them accessible to anyone willing to pay.
- Defending against DoS attacks involves filtering specific traffic signatures, while DDoS defense relies more on traffic analysis and scrubbing.
Head-to-Head Comparison Between DoS Attack vs DDoS Attack
| Feature | DoS Attack | DDoS Attack |
|---|---|---|
| Source of attack | Comes from a single source IP address or computer | Comes from multiple distributed source IP addresses or computers |
| Attack size | Generates up to 1 Gbps of traffic from a single source | Generates over 1 Gbps of traffic from multiple sources |
| Attack vector | Exploits a single vulnerability like consuming resources or crashing services | Exploits multiple vulnerabilities by using different attack vectors |
| Attack coordination | No central control or coordination | Uses a botnet or control server to coordinate attacks |
| Attack duration | Short-lived | Sustained over a longer period |
| Impact | Limited to disrupting access to a single target | Significantly disrupts access to multiple targets |
| Detection difficulty | Relatively easier to detect the single source | Difficult to detect all distributed sources |
| Mitigation methods | Block the single source IP or harden the targeted system | Requires coordination across multiple networks to block sources |
| Attacker identity | Individual attacker with some technical skills | Sophisticated groups using botnets and automation |
| Motivation | Ideological hackers or limited financial gain | Political, social or financial motivations |
Key Differences Between DoS and DDoS Attacks
While DoS and DDoS attacks share the same goal of denying services to legitimate users, there are some important distinctions between these types of malicious network activity:
Scale of Attackers
- A DoS attack involves one attacker’s computer flooding a target with requests from a single internet connection. This could be done by a single malicious actor controlling one computer.
- DDoS attacks utilize multiple attacking systems to coordinate and flood the target. Rather than originating from one point, the attack traffic comes from many distributed sources.
Attack Traffic Volume
- DoS attacks tend to have lower overall traffic volume because they originate from fewer sources. The volume from one computer and internet connection is more limited.
- DDoS attacks generate much higher volumes of traffic, hitting the target from many different directions. This distribution exhausts resources on many fronts.
Ease of Execution
- Performing a DoS attack requires an attacker to control a computer and write scripts or code to generate the flooding traffic. Technical skills are necessary.
- DDoS attacks do require a higher degree of technical skill to coordinate, but access to DDoS services for hire lowers the barrier. Even unskilled actors can rent a DDoS attack.
Methods of Attack
- DoS attacks typically rely on flooding the target with requests using a single attack vector, such as sending continuous HTTP requests to overwhelm a web server.
- DDoS attacks often employ multiple attack vectors concurrently. In addition to HTTP flooding, there may also be UDP, ICMP, or DNS floods from various sources.
Difficulty of Mitigation
- Once identified, DoS attacks from a single source IP address can be blocked. The traffic signature of the attack is easier to characterize.
- DDoS traffic originating from many sources across the internet makes blocking more challenging. More sophisticated traffic analysis and scrubbing solutions are required.
Impact on Target
- DoS attacks may temporarily impair services on the target, but modern systems are often able to withstand this limited onslaught.
- DDoS attacks generate so much distributed traffic that they can overwhelm systems and network defenses much more effectively, causing longer outages.
What are Common DoS Attack Tools and Methods
Performing a basic denial-of-service attack requires an attacker to control an internet-connected system and use it to overwhelm a target.
Here are some common tools and methods used to carry out DoS attacks:
- HTTP flood: Bombarding a web server with continuous HTTP requests can consume resources and crash the server if requests overwhelm capacity.
- Ping flood: Sending a constant stream of ICMP echo request packets to a target can overwhelm its connection or CPU resources.
- Slowloris: This tool opens many connections to a web server but very slowly sends headers across each one, overwhelming connection capacity.
- R.U.D.Y attack: Short for “R-U-Dead-Yet,” this flood sends HTTP POST requests very slowly to tie up threads on a web server.
- SYN flood: Continuous TCP SYN packet requests open up half-connections that can overwhelm a server’s connection state tables.
- UDP flood: A User Datagram Protocol (UDP) flood sends high volumes of UDP packets to random ports on a target system.
- NTP amplification: The attacker spoofs requests to public Network Time Protocol (NTP) servers, which send large responses to the target.
- DNS amplification: Similar to the NTP attack, this exploits publicly accessible DNS servers to flood targets with huge query responses.
What are the DDoS Attack Tools and Methods
Distributed denial-of-service attacks build on basic DoS methods but coordinate multiple attacking systems to overwhelm targets. Some common DDoS tools and techniques include:
- Botnets: Networks of compromised computers controlled by a central “bot herder” generate massive DDoS floods.
- Web scraping tools: To find poorly secured web systems, attackers scrape the internet, looking for exposed login pages to coopt.
- Peer-to-peer botnets: Decentralized P2P botnets like Gameover Zeus make takedowns more difficult because they do not have central command servers.
- IoT botnets: Hundreds of thousands of compromised Internet of Things (IoT) devices can be conscripted into botnets for large DDoS attacks.
- NTP amplification attacks: Rather than simple packet floods, NTP traffic is spoofed from many sources to reflect huge responses at the target.
- DNS amplification attacks: As with NTP amplification, publicly accessible DNS servers are exploited to flood targets with monstrous DNS query responses.
- Permanent DDoS services: Booter/stresser sites allow customers to pay to direct DDoS traffic at any target, requiring little technical skill.
- TLS-based attacks: Rather than unsecured protocols like DNS and NTP, attacks abuse TLS connections and encryption to bypass defenses.
DDoS services for hire have made these attacks accessible to anyone willing to pay. Emerging IoT botnets demonstrate the ease of compromising insecure devices to conscript them into DDoS swarms.
Real-World Examples of Major DDoS Attacks
Some of the largest DDoS attacks on record demonstrate the overwhelming force attackers can unleash against targets through distributed, multi-vector attacks:
- The massive 1.7 Tbps Memcached DDoS attack in 2018 remains the largest on record. Over 100,000 vulnerable Memcached servers were exploited to flood targets simultaneously.
- In 2018, GitHub was hit with the historic 1.35 Tbps attack, which leveraged vulnerable Memcached systems across the internet. The traffic overwhelmed GitHub for over 10 minutes.
- An 838 Mbps DDoS attack disrupted Amazon Web Services in 2020 using a wide combination of UDP, SYN, ACK, and HTTPS floods as attack vectors.
- In 2021, a 709 Gbps HTTPS DDoS attack leveraged encrypted TLS connections to bypass defenses and cripple content delivery provider Akamai for two hours.
- Exploiting the Windows RDP and Anycast protocols in 2022, Imperva fired a record-setting 787 million packets per second.
DoS vs. DDoS: Defending Against Each Type of Attack
The strategies and solutions for defending against DoS versus DDoS attacks differ significantly:
Defending Against DoS
- Block-specific IP addresses initiating DoS traffic floods.
- Write firewall rules to block traffic from a specific URL or point generating attack traffic.
- Use IPS/IDS solutions to detect and block traffic signatures of known DoS tools.
- Increase the capacity of servers and connections along with load balancing to handle more traffic volume.
- Implement tight login security protections like CAPTCHAs, lockouts, etc., to prevent attackers from gaining access to your systems to compromise them.
Defending Against DDoS
- Use traffic scrubbing services that can analyze patterns and absorb attack traffic originating from many sources.
- Implement anycast routing to distribute and withstand high traffic across multiple geographic scrubbing centers.
- Enable DDoS protection services from CDNs and cloud providers such as Cloudflare, Akamai, AWS Shield, etc.
- Expand network bandwidth to lessen the overall impact of floods. However, this is expensive and may not withstand the largest botnet attacks.
- Enhance logging and monitoring capabilities to identify anomalies indicating the early stages of a DDoS attack.
- Rapidly expand server capacity through elastic clouds to try absorbing inbound floods.
Final Thoughts
While denial-of-service (DoS) and distributed denial-of-service (DDoS) attacks share the same goal of denying services to users, their key characteristics differ significantly. DDoS attacks leverage botnets of many compromised devices across the internet to overwhelm targets from distributed locations. This distribution makes DDoS much harder to defend against compared to DoS attacks originating from a single source.
Understanding these key differences between DoS and DDoS informs security strategies. DoS may be defeated by filtering specific traffic signatures while combating DDoS, which requires cooperation between on-premise and cloud-based scrubbing capable of absorbing distributed floods. As DDoS attacks grow in size and sophistication, knowledge and preparation become mandatory to limit outages and damages.
Frequently Asked Questions About DoS vs DDoS Attacks
What is the difference between DDoS and DoS attacks?
The main difference is scale: DoS originates from one attacker system, whereas DDoS leverages multiple distributed attacker systems to overwhelm the target. DDoS attacks also often use numerous flooding methods for greater impact.
Where do DDoS attacks come from?
Most major DDoS attacks leverage large botnets of hundreds of thousands of compromised internet-connected devices. These devices range from compromised servers to hijacked consumer IoT devices.
Are DDoS attacks illegal?
Yes, DDoS attacks are illegal. When intentionally used to damage or impair systems, they are a form of cybercrime punishable by law in most jurisdictions worldwide.
How long do DDoS attacks last?
DDoS attack duration varies widely from short bursts lasting minutes to sustained attacks over weeks. The average attack lasts under 30 minutes, but the longest on record persisted for 13 days straight.
How do you stop a DDoS attack?
Defending against DDoS attacks requires a combination of on-premise infrastructure like routers and firewalls and cloud-based scrubbing services. Traffic needs to be diverted through large scrubbing centers to filter and absorb the floods.
What are common DDoS attack sizes?
Most DDoS attacks are under 1 Gbps in size. However, terabit-scale attacks are becoming more frequent, such as the 1.7 Tbps Memcached attack in 2018. Even small bursts can impair websites.
Do DDoS protection services work?
Reputable DDoS protection services can effectively filter large-scale network floods. Scrubbing centers analyze traffic to absorb DDoS attempts. Cloud services like Cloudflare can rapidly expand capacity to withstand sudden traffic spikes, too.
Jinu Arjun
