DoS and DDoS Resilience Testing

DoS and DDoS Resilience Testing

Why Simulate DoS and DDoS Attacks?

Simulating Denial-of-Service (DoS) and Distributed Denial-of-Service (DDoS) attacks is essential to verify that an organization’s critical systems can withstand overload and remain operational under pressure. These tests help identify weaknesses in network infrastructure, application services, and incident response capabiliti


Benefits of DoS/DDoS Attack Simulation

  • Verification of network and application infrastructure capacity.

  • Identification of bottlenecks and insufficient protection mechanisms.

  • Testing of real-time detection, mitigation, and response capabilities.

  • Validation of firewall, WAF, CDN, and anti-DDoS configurations.

  • Compliance with regulatory requirements (e.g. DORA, NIS2).


Typical Attacks and Differences Between DoS and DDoS

Attack Name Type Category Description
SYN Flood DoS/DDoS Volumetric Flooding the server with TCP connection requests
HTTP GET/POST Flood DDoS Application High number of legitimate requests from many clients
ICMP Flood DoS/DDoS Volumetric Flooding servers with ICMP requests
Slowloris DoS Logical Keeping HTTP connections open with incomplete headers

Key Objectives of DoS and DDoS Testing

  • Simulation of overload attacks on critical systems to determine their performance limits.

  • Verification of mitigation mechanisms at both the network and application layers.

  • Testing incident response processes and coordination between IT and SOC teams.

  • Identification of vulnerabilities at system entry points.

  • Evaluation of the resilience of third-party services (e.g. DNS, CDN, cloud hosting).


How Does the Testing Work in Practice?

  • Preparation phase – defining the test scope, identifying critical systems, and obtaining necessary approvals (e.g. from cloud service providers).

  • Attack simulation – executing controlled DoS/DDoS scenarios using different vectors such as SYN flood, HTTP flood, UDP flood, Slowloris, etc.

  • Monitoring and metrics collection – recording performance data and the status of target systems, including the impact on SLAs.

  • Analysis and reporting – evaluating the effectiveness of defense mechanisms, documenting findings, and proposing mitigation measures.

  • Retesting (optional) – verifying remediation measures and confirming improved resilience after their implementation.

What Requirements Does DORA Set for DoS/DDoS Testing?

In accordance with the European DORA regulation, organizations are required to:

  • perform performance and stress testing of critical systems (e.g. DoS/DDoS simulations), particularly for services essential to business stability and continuity,

  • include scenario-based testing (including load/DoS scenarios) and coordinate with relevant third parties where appropriate, depending on the nature of the services. Organizations should involve qualified and independent testing teams with proven DoS/DDoS expertise. While DORA does not mandate specific certifications, it requires demonstrable team competence,

  • ensure proper documentation of results, propose remediation measures, and conduct follow-up testing where necessary,

  • integrate findings into the organization’s broader cyber resilience and incident preparedness strategy,

  • maintain the independence of the testing team from development teams, IT operations, and infrastructure providers.


What Are the Requirements for Testing Teams?

  • Professional expertise in network security and traffic engineering.

  • Experience with anti-DDoS technologies such as Cloudflare, Arbor, Radware, and Akamai.

  • Independence and credibility – internal teams must be separated from operations; external providers must demonstrate insurance coverage and confidentiality commitments.

  • Understanding of legal aspects – strong emphasis on proper authorization, supervision, and the legal boundaries of testing.


Why Work with BDO?

BDO provides DoS/DDoS attack simulations as part of a comprehensive cyber resilience testing strategy in line with European regulations such as DORA and NIS2, as well as recognized standards including ISO 27001 and OWASP.

Technical expertise and experience
Our team has specialized knowledge in network attacks, infrastructure testing, and anti-DDoS defense configurations. We have experience testing even the largest financial institutions and operators of cloud platforms.

  • Knowledge of DORA, NIS2 and TIBER-EU
We understand DORA requirements and can adapt testing so that the outputs can be used for regulatory supervision and audits. We help establish a testing strategy and ensure alignment with other testing approaches (TLPT, penetration testing).

  • Independence and credibility
As an independent consulting firm, we deliver objective and reliable results. Our work provides a strong signal of quality for regulators as well as for a client’s internal management.

  • Certified team with professional experience

Our specialists hold certifications from organizations such as OSCP, CRTP, eCPPT, BSCP, CEH, CRT, CPSA, CISSP, CCISO and others. They have experience testing large banks, insurance companies, and ICT service providers.

OSCP eCPPT RedTeam PenTest CEH CREST CISO CISSP

Main contacts

Martin Hořický
Martin Hořický
Partner • Digital Services
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Marek Kovalčík
Chief Information Security Officer • Digital Services
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