Distributed denial-of-service (DDoS) attacks remain a severe cyberthreat to businesses and organizations as increasing volumes continue disrupting operations. This comprehensive overview chronicles the inner workings of the 16 most common DDoS vectors that security teams defend against daily.
What are Distributed Denial-of-Service Attacks?
A distributed denial-of-service (DDoS) attack refers to a cyberattack intended to overwhelm a server, network, or infrastructure with a flood of internet traffic in order to make online services unavailable. DDoS attacks are distributed because threat actors enlist and control large networks of remotely compromised devices, collectively called botnets, to carry out attacks.
By crashing critical systems and choking bandwidth, DDoS attacks inflict serious damages including:
- Loss of sales and productivity
- Erosion of consumer trust, reputation
- Leaked data assets
- Infrastructure outages
To grasp today‘s stakes, the number of DDoS attacks increased an astounding 90% year-over-year jump in 2021 according to NETSCOUT research. Left unchecked, this dangerous trend empowers disruption across industries.
Categorizing Modern DDoS Attack Vectors
Hacking innovators continually evolve tactics to inflict maximum damages through newer, stealthier DDoS techniques. To instill resilient defenses, IT security teams must deeply grasp the leading attack types surfacing daily.
This guide categorizes prevailing DDoS vectors across three groups—volumetric, protocol, and application-layer—as summarized below:
| Volumetric Attacks | Protocol Attacks | Application-Layer Attacks |
|---|---|---|
| Flood infrastructure to consume all bandwidth | Exploit network protocol weaknesses for DoS | Directly target and crash applications |
Having established a framework of major DDoS species, next we unravel key attack techniques through an anatomy-focused eight attack types per group.
Volumetric DDoS Attacks
The essence of volumetric DDoS involves flooding targets with more traffic than infrastructure can accommodate. These brute force methods rapidly choke bandwidth, disconnecting legitimate users.
Volumetric attacks account for an outsized 80% of DDoS events last year per Kaspersky telemetry. Top tactics include:
UDP Flood
[…]NTP Amplification
[…]HTTPS Floods
As web properties shift toward near-ubiquitous TLS encryption, so have DDoS traffic profiles. Imperva observed over 75% of network layer attacks leveraging HTTPS rather than HTTP for added stealth. HTTPS attacks also exploit expensive decryption server-side to increase effectiveness significantly…
Protocol DDoS Attack Techniques
Rather than brute bandwidth saturation, protocol attacks exploit inherent weaknesses in foundational protocols like TCP, UDP, and ICMP against which modern networks are built.
By surgically crashing devices and processes, attackers sidestep many legacy DDoS defenses. Total events decreased to 15% of occurrences last year, but risks remain high for unpatched gear.
Prominent protocol attack types include:
TCP SYN Floods
TCP underpins all web transactions and data flows. Abusing the three-way handshake process to open fraudulent sessions taxes finite server resources quickly. SYN floods accounted for over 17% of DDoS attacks in 2021 per NETSCOUT…
ICMP Fragmentation Attacks
While basic ICMP floods top 5% of attacks, more advanced fragmentation variants evade defenses by dividing malicious payloads across packets. Reassembling these exhaustive fragments consumes processor and memory resources…
Ping of Death
Among oldest yet still dangerous protocol attacks, manipulating fragmented ping packet sizes crashes unpatched systems attempting to reorder and reassemble. Highly effective for fire-and-forget strikes despite lesser use presently…
Breaking Down Application-Layer Assaults
The most sophisticated class of DDoS attacks target web applications and DNS servers themselves rather than just the networks. Even minimal traffic applied against specific vulnerabilities crashes sites by draining critical backend resources.
Low-volume application-layer attacks draw scarce detections while inflicting total site outages and severe business impacts. Top attack types include:
HTTP Request Floods
Simple HTTP GET/POST floods prove highly effective application attacks by rapidly depleting web server resources. Requests open legitimate connections so basic IP blocking fails against randomized botnet sources. Slow request techniques further intensify effectiveness…
Cross-Site Scripting (XSS)
Injecting malicious scripts through web apps forces browsers to dedicate resources until exhausted. XSS remains a widespread menace ranking as the most common website vulnerability per Watchguard. Integrating XSS into broader vulnerability exploit campaigns multiplies harms…
SQL Injection Attacks
By passing manipulated SQL queries, attackers trick database servers into resource-intensive operations involving complex responses, table scans, stored procedure calls ultimately crashing apps and locking business operations…
Inside DDoS Cybercrime: Financially Motivated Mayhem
Having explored technical terrain across dozens of DDoS attack types, what drives the acceleration of volumes in recent years comes down to rampant financial criminalization of these threats.
DDoS intrinsically links to extortion, disruption, and notoriety fueling shadowy underground markets. Crippling attacks now operate as turnkey mercenary services, as examined below:
DDoS Booter Services
Dubbed “DDoS booters” or “stressers,” black market providers allow novices to launch attacks through fully automated web interfaces at volumes exceeding 500 Gbps for fees as low as $10 per hour. Major booter busts in 2021 dismantled destructive groups Dark Shell and Ragnar Locker.
Ransom DDoS Extortion
Increasingly brazen extortion tactics now account for 25% of DDoS motivations according to Kaspersky. Nearly two-thirds of enterprises received ransom demands paired with short demonstration attacks showing groups’ fearsome capabilities. Law enforcements advise never paying.
DDoS Platform-as-a-Service
A tier of specialized DDoS merchants sell toolkits and access to vast IoT botnets exceeding over 1 Tbps firepower. One dominant Russian-language provider dubbed “Merchant of Death” powered waves of mega attacks before 2021 takedown. Buyers can launch nearly unlimited custom attacks.
Incentives around disruption-for-hire continue growing more extreme, necessitating equally robust defenses across detection, prevention, and mitigation disciplines.
8 Core Strategies for Stronger DDoS Defenses
Gaining advantages against the thriving DDoS underground begins with integrating layered controls aligned to attack scenarios detailed herein:
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Engage DDoS Mitigation Services: Route traffic through always-on scrubbing networks filtering known attacks at scale before reaching you.
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Harden Infrastructure: Increase bandwidth, upgrade legacy gear, mandate multi-factor authentication universally, apply latest IOS patches continually.
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Load Balance Strategically: Distribute workloads across larger server pools to withstand surges. Ensure sufficient outbound capacity and uplink redundancies.
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Monitor Vigilantly: Inspect network traffic, system metrics, and logs to establish attack baselines. Profile bandwidth, latency and suspicious traffic emergence revealing attacks.
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Test Realistically: Probe defenses via simulations reflecting real-world attacks. Assess and improve through red teams, penetration testing, and purpose-built DDoS services.
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Map Dependencies: Inventory all upstream providers in your ecosystem. Catalogue hardware assets by geolocation and ownership to understand attack surfaces.
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Plan Thoroughly: Document response processes assigning cross-team duties across detection, validation, coordination, public relations, and technical remediations.
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Practice Regularly: Run mock drills to sharpen responses and debrief learnings for future plan iterations. Validate notifications work and providers demonstrate effectiveness.
With attacks intensifying dramatically year over year, achieving resilience requires action across these pillars transformed into mature capabilities. Prioritizing progressive enhancements ultimately determines an organization‘s readiness.
The Fight Against DDoS Pushes Forward
As online properties grow more essential across virtually every industry, so do the incentives for attackers to disrupt operations through overwhelming floods of debilitating internet traffic.
Evolutions in tactical innovations, financial motivations, and shockingly accessible attack tools necessitate security leaders continually adapt defenses in response. Developing expert-level fluency across the DDoS attack landscape detailed here marks the first step toward driving capability improvements over the endless horizons ahead.
