--- title: "SS7 and Diameter Protocol Vulnerabilities" --- SS7 and Diameter Protocol Vulnerabilities: Telephony Interconnect Security: SMSRiver - [Skip to main content](#main-content) [ smsriver.com ](/) [Public Inboxes](/#numbers-section) [Country Codes](/country-codes/) [Workbench](/workbench/) [Tools](/tools/) [Developer API](/developer/) [Pricing](/pricing/) [Log In](/accounts/login/) [ Log In ](/accounts/login/) [ Get API Key ](/pricing/) [ Home ](/) - [ Articles ](/articles/) - Telecom Regulations & A2P 10DLC Telecom Regulations & A2P 10DLC Published 2026-08-31 • 9 min read # SS7 and Diameter Protocol Vulnerabilities: Telephony Interconnect Security Technical analysis of Signaling System 7 (SS7) and Diameter routing flaws. Understand interception threats, location tracking, and SMS authentication interception. Key Takeaway & Executive Summary SS7 protocol trust models assume all connected telecom carriers are benevolent, enabling sophisticated adversaries to intercept SMS verification codes remotely. Signaling System 7 (SS7) was designed in the 1970s for routing calls between trusted state-owned monopolies. Today, thousands of private carriers, MVNOs, and aggregators have SS7 access, creating massive signaling interception risks for SMS-based authentication. ## Table of Contents - [ The SendRoutingInfoForSM Interception Attack ](#section-1) - [ Frequently Asked Questions ](#frequently-asked-questions) ## 1 The SendRoutingInfoForSM Interception Attack When an SMS is dispatched, the sending switch queries the Home Location Register (HLR) using SRI-SM (Send Routing Info for Short Message) to locate the recipient's serving MSC. Threat actors with leased SS7 signaling access forge updateLocation requests to redirect incoming SMS to their own virtual receiver. ## Frequently Asked Questions • Telecom Regulations & A2P 10DLC Can end users protect themselves against SS7 attacks? End users cannot block SS7 attacks directly. Protection requires switching to app-based TOTP or hardware security keys (FIDO2) for high-value accounts. ## Related Technical Articles & Deep Dives [ OTP & 2FA Engineering 8 min read ### SMS 2FA vs TOTP Authenticator Apps: Security Risk Assessment ](/articles/two-factor-sms-vs-totp-security/) [ OTP & 2FA Engineering 8 min read ### Silent Network Authentication (SNA) vs SMS OTP: Security & Cost Tradeoffs ](/articles/silent-network-auth-vs-sms-otp/) [ Telecom Regulations & A2P 10DLC 9 min read ### SMPP v3.4 Protocol Explained: PDUs, Enquire Link, and Telco Peering ](/articles/smpp-protocol-explained-for-developers/) Developer Sandbox ### Automate Inbound SMS & OTP Testing Eliminate flaky 2FA in CI/CD. Access dedicated virtual lines, programmable synthetic SMS webhooks, and Model Context Protocol (MCP) integrations. 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