Quick answer: Telecom cyber security protects the networks that carry voice, data and internet traffic. Operators face state-sponsored espionage targeting core infrastructure, abuse of signaling protocols such as SS7, SIM swapping fraud, attacks on network equipment and denial-of-service attacks. Key defenses include hardening network devices, securing management access, filtering signaling traffic, protecting subscriber accounts and managing supply chain risk.
Telecommunications networks are critical infrastructure: almost every other sector depends on them. That makes operators attractive targets for criminals and nation-state groups. This guide summarizes the main threats and the controls that matter most.
Main telecom threats
| Threat | What happens | Key defense |
|---|---|---|
| Espionage on core infrastructure | Attackers access routers and lawful intercept or call records | Device hardening, monitoring, secure management access |
| Signaling abuse (SS7, Diameter) | Location tracking, call and SMS interception | Signaling firewalls and filtering |
| SIM swapping | Attackers hijack phone numbers to bypass SMS codes | Stronger customer verification, port-out protection |
| DDoS attacks | Service outages for customers | Scrubbing capacity and traffic engineering |
| Supply chain compromise | Vulnerable or tampered equipment and software | Vendor assessment, SBOMs, patch management |
Many of these threats affect customers who never interact with the operator’s security team. A weakness in signaling or account verification can expose millions of subscribers at once.
Defensive priorities for operators
- Harden network equipment and remove unused services; government guidance on enhanced visibility and hardening for communications infrastructure sets out concrete steps.
- Isolate management networks and require multifactor authentication for administrators.
- Monitor configurations and traffic for unexpected changes.
- Filter signaling traffic from roaming partners.
- Protect subscriber accounts against SIM swap and port-out fraud.
- Manage vendors with security requirements and visibility into components.
What customers can do
- Use authenticator apps or passkeys instead of SMS codes; see FIDO2 vs WebAuthn.
- Set a carrier account PIN and port-out protection; see SIM-jacking countermeasures.
- Use end-to-end encrypted messaging for sensitive conversations.
Signaling weaknesses are explained in our guide to SS7 protocol vulnerabilities. Related topics include supply chain attacks and layered cyber security. CISA also covers the communications sector.
Related reading
Two-Factor Authentication Methods Compared: SMS, Apps, Keys and Passkeys
Frequently asked questions
Why are telecom companies targeted by hackers?
They carry communications for governments, businesses and individuals, so access offers intelligence, fraud opportunities and the ability to disrupt services.
What is an SS7 attack?
It abuses the SS7 signaling protocol used between telecom networks to track phones or intercept calls and text messages.
How does SIM swapping work?
Attackers convince or bribe a carrier to move a victim’s number to a SIM they control, then use it to receive verification codes.
Is 5G more secure than 4G?
5G includes stronger security features, such as better protection of subscriber identities, but its security still depends on how operators deploy and configure it.
Conclusion
Telecom security protects infrastructure everyone depends on. Operators must harden equipment, secure management access, filter signaling and protect subscriber accounts, while customers should move away from SMS-based verification. Both sides reduce the risk of large-scale compromise.
