MNP (Mobile Number Portability)

Mobile Number Portability lets subscribers change operator while keeping their MSISDN, mandated by regulators in most markets. It is implemented through a national number portability database that operators query during call/SMS routing. MNP processes are also a frequent attack surface for SIM-swap-style social engineering, where an attacker ports the victim's number to an operator they control.

Categories: Identity and SubscriberSecurity ControlsThreats and Attacks

MNP in context

Subscriber identifiers (IMSI, SUPI, MSISDN, IMEI) are the anchor for authentication, charging, lawful interception and fraud analytics. Any protocol or interface that leaks a permanent identifier is treated as a serious privacy defect, which is why 5G introduced SUCI concealment on the air interface.

Security controls in telecom span signaling firewalls (SS7/Diameter/GTP screening at the network edge), transport encryption (IPsec, TLS, PRINS), identity and access on OSS/BSS, and monitoring at both the packet and log level. Controls are audited against GSMA FS.11/FS.19/FS.20/FS.36 and, in Europe, NIS2 sectoral rules.

To place MNP in the wider telecom-security picture, review CLI Spoofing, IMEI, RPKI, STIR, SIM Swap and Port-Out Fraud.

Related terms

Related topic hubs

  • Diameter Attacks S6a IDR/PUR/CLR abuse, subscriber tracking, LTE signaling attacks.
  • SMS Firewall SMS spam, phishing, A2P bypass and MAP-layer SMS filtering.
  • Signaling Firewall Unified SS7/Diameter/GTP/SMS signaling firewall framework.
  • Silent SMS Type-0 SMS location tracking and detection.

More from the TelcoSec Glossary

Browse the full TelcoSec Glossary, the Ultimate Guide to Mobile Network Security, or the P1 Arsenal of telecom-security tools.