DDoS Attacks on Telecom Infrastructure — Defense and Mitigation

Why telecom is a DDoS target

Telecom operators are natural DDoS targets — their infrastructure carries traffic for millions of users. A successful DDoS attack on an operator is not just a website outage — it paralyzes services: telephony, internet, business data transmission, critical services (emergency calls, banking). In 2025, DDoS attacks on the European telco sector increased significantly. The record attack on a European operator reached 3.2 Tbps. Motivations: geopolitical hacktivism, financial extortion, competitor attacks, and diversion masking another intrusion.

DDoS attack techniques targeting operators

Volumetric attacks

Bandwidth-saturating attacks: UDP flood, DNS amplification, NTP reflection. Operators with 100 Gbps links can be overwhelmed by attacks many times larger.

Protocol attacks

Network protocol attacks: SYN flood, fragmented packet attacks, BGP hijacking combined with DDoS. Targeting operator routers and firewalls.

Application layer attacks

Attacks on application layer: HTTP flood on customer portals, DNS query flood on operator DNS servers, attacks on BSS/OSS systems.

Multi-vector attacks

Combined techniques: simultaneous volumetric attack masking a precision application layer attack. Most difficult to mitigate.

Impact of DDoS attacks on telecom services

Service unavailability — telephony, internet, and data transmission outages. Subscribers without connectivity, businesses without communication.

Critical services — threat to emergency numbers (112/911), banking services, telemedicine, and other connectivity-dependent services.

Financial losses — lost revenue (SLA), regulatory fines (NIS2), mitigation and recovery costs, customer churn.

Cascade effect — attack on one operator can overload peering and transit, affecting other operators.

Defense methods for telecom operators

1. Scrubbing centers — dedicated traffic cleaning centers. Suspicious traffic routed through centers that filter attacks while preserving legitimate traffic.

2. BGP Flowspec — dynamic filtering rules deployed directly on edge routers. Enable rapid response without rerouting all traffic.

3. Anycast DNS — DNS servers distributed across multiple locations. Attack load spreads across all instances.

4. Rate limiting and traffic shaping — limiting traffic from suspicious sources, prioritizing critical service traffic.

5. Upstream provider cooperation — blackholing and Remote Triggered Blackhole (RTBH) at transit providers. Defense at a higher level.

6. SOC with DDoS monitoring — automatic traffic anomaly detection, immediate mitigation activation, correlation with threat intelligence.

7. Redundancy and overprovisioning — excess bandwidth absorbing smaller attacks, redundant network paths.

The operator customer’s perspective — what the Polish Plenipotentiary’s October 2026 recommendation means for companies using internet providers’ services — is covered in our article on what the DDoS recommendation for ISPs means for companies.

Companies that are the operator’s customers can check how their links and services will behave during an attack, and whether the switchover to scrubbing will work, in a controlled DDoS resilience test.

Cybersecurity for Your Industry

Learn more about cybersecurity in your industry:

• Cybersecurity for Telecommunications

Best practices for implementation

Effective implementation requires several key steps:

1. Risk assessment and inventory — identify assets, threats, and vulnerabilities specific to your organization.
2. Policy development — document requirements, roles, and responsibilities.
3. Technical controls — deploy tools and configurations proportionate to identified risks.
4. Training and awareness — engage employees in protecting organizational security.
5. Monitoring and continuous improvement — regularly verify effectiveness and adapt to the evolving threat landscape.

Related topics

See also:

• NIS2 for hospitals — compliance

Related terms

• SOC

Our services

• NIS2 for hospitals — implementation and compliance
• NIS2 for local government — municipalities implementation

Related services and products

• IT Infrastructure Management Automation
• External IT Infrastructure Penetration Testing
• Cyberoo I-SOC