A2P SMS Termination Bypass: A Constantly Evolving Threat
Wed Apr 02 2025
A2P SMS bypass fraud is not a static challenge—it constantly evolves as fraudsters adapt to new controls and exploit fresh vulnerabilities.
Over the years, bypass methods have shifted from basic SIM box fraud to grey routing, international breakout schemes, and sophisticated signalling exploits. In a recent case, we encountered an emerging bypass tactic in which roaming signalling links were used to terminate A2P traffic without passing through the SMSC or firewall.
Fraudsters obtained IMSI data—whether harvested, hacked, or acquired through other means—and used it to send SMS requests directly to terminating switches using spoofed Global Title addresses. By systematically attempting delivery across multiple switches, they identified the correct host MSC while simultaneously harvesting additional subscriber information for future attacks.
This case is a stark reminder that as telcos strengthen controls, fraudsters continuously innovate to find new weak points. Each new bypass technique leads to direct revenue loss and creates data security risks, exposing customer information that can be used in future fraud attempts.
The ability to adapt detection and prevention strategies is critical. A2P SMS termination remains a valuable revenue stream, but operators risk losing control over their earnings and network integrity without proactive defence.
A2P SMS Revenues Are Under Siege: How Fraudsters Are Exploiting the System
The A2P SMS market is projected to reach $111.6 billion by 2032. However, as international termination fees rise, fraudsters innovate new bypass techniques to exploit arbitrage opportunities.
Common A2P Bypass Methods
| SIM Box Fraud | Using banks of consumer SIM cards to route A2P messages as P2P, avoiding interconnect fees. |
|---|---|
| Grey Routing | Exploiting loopholes in routing agreements to terminate A2P SMS via unauthorized routes. |
| Alternative Termination Methods | Terminating SMS traffic via WhatsApp, Telegram, and Flash Calling, reducing SMS termination fees. |
| Local Breakout | Injecting international A2P SMS into domestic networks to avoid international termination charges. |
| Signalling Abuse(New) | Using hacked IMSI data to bypass SMSCs and firewalls by sending SMS messages directly to MSCs, allowing for A2P message termination without operator revenue capture. |
The Scale of the Problem
- $38.95 billion was lost to telecom fraud in 2023, 2.5% of global telecom revenues.
- Artificial Inflation of Traffic (AIT) fraud reached $1.16 billion in 2023, artificially increasing operator costs.
- 5% of all international A2P traffic is fraudulent, with enterprises unknowingly paying for fake or bypassed messages.
- 47% of global consumers received unsolicited SMS messages in 2023, further damaging trust in SMS.
(Source 1,2)
With telco revenue growth slowing globally, protecting A2P revenues is more than just a fraud issue—it’s a strategic imperative.
A2P SMS Remains a Strategic Revenue Stream—Vigilance is Key
As mobile penetration reaches saturation in many markets, operators must maximize high-margin revenue streams like A2P SMS. Yet, without proper vigilance, these revenues will continue to leak.
Why This Matters More Than Ever
- Telco growth rates are at historic lows, making fraud prevention financially necessary.
- Bypassed SMS traffic reduces visibility and control, impacting trust and enterprise customer retention.
- Security vulnerabilities are amplified significantly when OTP and banking authentication messages are compromised.
Operators must step up their game in detection and prevention—reactive strategies won’t suffice.
Best Practices: Proactive Strategies to Stop A2P Bypass
Telcos need a multi-layered strategy that combines network security, advanced fraud detection, and continuous monitoring to effectively combat A2P SMS bypass.
| Strengthen Global Title (GT) Management | Whitelist & Blacklist GTs – Prevent fraudsters from injecting unauthorized traffic into your network. Adopt GSMA’s Global Title Leasing Code of Conduct. This ensures that only verified and legitimate network infrastructure is used for A2P termination. Monitor GT Traffic – Track anomalies in originating and terminating GTs to detect suspicious spikes in A2P SMS. |
|---|---|
| Firewall & Content Filtering | Monitor for A2P Patterns on P2P Routes – Identify business-related message patterns disguised as personal communication. International & National Route Separation – Ensures strict A2P and P2P traffic segmentation to prevent unauthorized routing. Deploy AI-Based SMS Firewalls – Uses machine learning to detect routing anomalies and fraudulent SIM behaviour. Real-Time SS7 Firewall Deployment – Detects unusual signalling requests, such as repeated Send Routing Info (SRI) requests, which are used to harvest IMSI data for bypass fraud. |
| Proactive Fraud Testing & Monitoring | Ongoing Independent Route Testing – Actively tests message routes to detect unauthorized bypass routes before fraudsters exploit them. Live Monitoring of Traffic Spikes – Identifies sudden surges in A2P traffic disguised as local P2P messages. Machine Learning for Anomaly Detection – Uses AI to learn evolving fraud tactics and flag suspicious behaviour in real time. |
| Tighten Number Plan Management at the MSC Level | Block Unallocated Ranges – Prevents fraudsters from using non-existent numbers for Flash Calling fraud. Implement Strict Rate-Limiting for Authentication Messages. This will Reduce AIT fraud, where bots artificially inflate SMS traffic to exploit enterprise billing. Use Number Intelligence APIs – Pre-validate number legitimacy before messages are terminated. |
| Strengthen Industry Collaboration & Regulation | Engage in Industry Data Sharing – Fraudsters reuse the same tactics across markets, making cross-operator intelligence critical. Participate in MEF’s SMS SenderID Protection Registry – Helps telcos and enterprises lock out fraudsters using brand impersonation. Advocate for Stricter A2P Messaging Standards – Push for mandatory sender verification to eliminate grey routes. |
Final Thoughts: Intelligence Sharing is the Key to Staying Ahead
A2P SMS remains a strategic, high-margin revenue stream for telcos. But fraudsters are evolving faster than ever—exploiting roaming signalling, grey routes, and SIM boxes to divert billions in revenue.
The battle against A2P SMS bypass fraud cannot be fought in silos. Fraudsters operate across multiple networks, exploiting gaps in coordination between telcos. Fraud trends will continue to outpace defensive measures without active intelligence sharing across the industry.
Operators must collaborate and share real-time threat intelligence to stay ahead of evolving bypass schemes. Industry-wide fraud monitoring and proactive testing will be critical to closing vulnerabilities before they are widely exploited.
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About Orillion
Orillion Solutions is a leading provider of solutions that unlock value for customers by using advanced data insights, innovative technology, and rapid solution design methods to help solve complex business and risk management problems. This includes the delivery of the largest fraud blockchain network in telecommunications, which is helping telcos and their customers prevent fraud more effectively.
About Soramitsu
Soramitsu is an award-winning global technology company with expertise in developing blockchain-based solutions for digital asset and identity management. Our mission is to use blockchain to promote innovation and solve pressing societal challenges. Soramitsu aims to deploy cutting-edge technology on a global scale in order to expedite financial inclusion and health, mitigate economic inefficiencies, and contribute to the fulfilment of the Sustainable Development Goals.