HI2 (Lawful Interception (Handover Interface 2))

The interface delivering content of communication from the network to law enforcement per ETSI LI model. HI2 carries intercepted communications (voice, SMS, data) along with associated metadata.

Categories: Security ControlsThreats and AttacksProtocols and Standards

HI2 in context

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.

Telecom threats range from opportunistic SMS phishing and SIM swap to nation-state grade location tracking and lawful-interception abuse. The common thread is that most attacks exploit the inherited trust model of legacy signaling. SS7 and Diameter were designed for a closed operator community that no longer exists.

To place HI2 in the wider telecom-security picture, review HI3, HI1, Mediation Device (Lawful Interception), OAM, X3 (LI) and Cipher Downgrade Attack.

Related terms

Equipment

Lawful interception systems (ADMF, mediation, HI1/2/3)

Articles in the P1 mobile network security guide

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.

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.