Work through it, tick as you go.
- Inbound A2P and interconnect trafficFrom aggregators and international partners
- SMS firewallInspects every message in real time
- Operator SMSCOnly clean traffic is delivered
- Subscriber handset
- Grey routes, spoofed sender IDs and spam are blocked
- Legitimate A2P traffic is identified and billed
AIT / SMS pumping (artificially inflated traffic)
Fraudsters trigger legitimate-looking OTP/verification sends to numbers they control, inflating a sender's bill. Often run through complicit or compromised routes.
- Rate-limit verification requests per number, IP, device, and account.
- Monitor conversion (code entered) per destination — pumped traffic has near-zero conversion.
- Alert on sudden volume to unusual country/number ranges.
- Add challenge/CAPTCHA on velocity spikes and cap resends per session.
- Validate numbers with HLR / number intelligence before sending.
- Partner with a provider that offers AIT detection and route-level intervention.
SIM-box & interconnect bypass
SIM boxes terminate international traffic as local, stealing operator termination revenue and degrading quality.
- Deploy test-call / test-SMS generation to detect off-net termination (A-number mismatch).
- Analyse CDRs for SIM-box signatures: high fan-out, low mobility, unusual call patterns.
- Correlate signalling and traffic data to flag numbers behaving as gateways.
- Maintain block lists and feed detections back into the firewall/switch in near-real-time.
- Coordinate with interconnect partners on suspected bypass routes.
Smishing & sender-ID spoofing
SMS phishing impersonates trusted brands to steal credentials; spoofed sender IDs make it convincing.
- Operate a sender-ID registry / whitelist and block unregistered use of protected IDs.
- Scan message content for phishing URLs and category-filter known-bad domains.
- Deploy an SMS firewall with impersonation and spoofing detection.
- Provide subscriber reporting (e.g. spam-forwarding shortcode) and act on reports.
- Educate enterprise senders on consistent, verifiable branding.
Grey routes & A2P leakage
A2P traffic delivered as P2P to dodge termination fees — the largest single messaging-revenue leak for many operators.
- Home-route MT-terminating traffic through the firewall to close the bypass gap.
- Detect SS7 MT-bypass and MO-faking patterns at the signalling layer.
- Enforce A2P commercial policy: only registered, billed enterprise senders reach subscribers.
- Reconcile per-route to quantify leakage recovered after enforcement.
- Reference GSMA IR.71 / FS.11 controls when defining detection rules.
Wangiri & voice-related fraud
Wangiri ('one ring and cut') and revenue-share fraud lure victims into calling premium/international numbers.
- Detect one-ring / short-duration inbound bursts from premium-rate ranges.
- Block or challenge outbound calls to high-risk international premium destinations.
- Monitor for IRSF (international revenue-share fraud) test-call patterns.
- Rate-limit and alert on abnormal call-back volumes to flagged ranges.
- Share intelligence with interconnect partners and industry fraud forums.
Governance & continuous improvement
- Assign a clear owner and escalation path for each fraud category.
- Maintain a threat-intelligence feed and update detection rules regularly.
- Run periodic red-team / test-traffic exercises to validate controls.
- Track fraud KPIs: leakage recovered, false-positive rate, mean time to detect/block.
- Align controls with GSMA fraud & security guidance and your regulator's requirements.
Standards and regulator references cited in this guide. BroadNet is a GSMA Associate Member and MEF member operating carrier-grade messaging since 2003.