Flash Calls & Flash Call Fraud: What Telecom Operators Need to Know

Many apps and services are moving beyond SMS-based 2FA/OTP (one-time password) methods. One of the most talked-about alternatives is flash calls. On the face of it, they offer speed, ease, and cost savings. But for telecom operators (CSPs / MNOs), there are real risks ; lost revenue, fraud exposure, and network strain. Let’s explore what flash calls are, how flash call fraud can happen, what impact this trend is having (or will have), and what operators can do to protect themselves, or even turn the trend into an opportunity.

What are Flash Calls (Flash Call Verification)?

At a high level:

• A “flash call” is an ultra-short, machine-generated call made to a user’s phone number for the purpose of verification/authentication. The call is not meant to be answered. The app that initiated the call or verification system reads some part of the metadata (often the CLI or Caller Line Identifier, particularly the last few digits of the calling number) from the incoming missed call, and uses that as the verification token.
• There’s no SMS involved; no user input (or minimal). The process is often seamless from the user’s point of view.
• It generally works only when apps have permissions to read incoming call metadata/call logs (Android more than iOS), because iOS limits what apps can read of call activity.

Because flash calls don’t require the user to pick up or even read an SMS, they are faster and, for the app maker / OTT service, often cheaper than sending A2P SMS for authentication.

How Flash Call Fraud or Abuse Can Work

Flash calls by themselves are not necessarily fraudulent; they are just a verification alternative. But they open up new avenues of abuse or revenue leakage. Some key vectors:

1. Undetected Flash Calls & Revenue Leakage
   Because the calls are not answered, many traditional telecom billing / call detail record (CDR) systems do not flag them as billable events. Apps or services use them instead of SMS OTPs to save money. Telecoms lose the A2P SMS revenue they would have had.
2. Bypassing Existing Authentication / Verification Channels
   Some services adopt flash calls instead of SMS OTP or voice OTP. This allows them to sidestep the interconnect or billing arrangements that telecoms have around SMS or voice.
3. Potential for Fraud or Misuse
   • Since flash calls rely on reading call metadata, there is risk of caller ID spoofing or number manipulation in call routing. The last digits used as verification might be manipulated.
   • Actors could send flash calls from questionable or malicious sources; trust / transparency issues arise.
   • Because users see a missed call without necessarily expecting it, there are risks of phishing/scam: e.g. malicious actors mimicking legitimate flash call verification, or abusing trust built around “you’ll get a missed call”.
4. Strain on Network & Signaling Load
   Flash calls, though short, still generate signaling traffic. They might not generate voice duration revenue, but they consume network resources (call setup, routing, logging), which in large volumes can affect network performance.
5. Regulatory / Legal Risk
   In some jurisdictions, using automatic flash calls might run afoul of telecom regulation, privacy laws, or consumer protection. Operators need to know whether flash calls, particularly when automated, are legal, accepted, or require user consent.

The Impact on Telecom Operators & Revenue

Flash calls represent a serious challenge to the traditional revenue models of mobile network operators. One of the most significant consequences is the erosion of A2P SMS revenue. Since flash calls bypass SMS-based authentication, every verification that would have generated an SMS charge instead goes unnoticed, creating a direct hit on operator income. At the same time, the volume of flash calls is growing rapidly worldwide, and even a small cost per call, multiplied at scale, translates into substantial lost revenue opportunities.

For operators, the issue is compounded by the cost-to-revenue imbalance. While flash calls consume signaling and network resources, they typically do not produce billable events since the call is never answered. This means operators must still handle the traffic but without the benefit of associated revenue, gradually undermining the profitability of their A2P business.

In addition, network performance is at risk. The rising number of short-duration calls increases signaling load and can strain network infrastructure. To cope, operators may need to invest in monitoring, detection tools, or firewalls to differentiate flash calls from legitimate traffic. These added operational and capital expenses reduce margins even further.

Finally, there is the matter of competitive pressure and business model disruption. Over-the-top (OTT) service providers and app developers favor flash calls because they are faster and cheaper than SMS. This shift in authentication traffic diminishes operator control over a revenue channel that has historically been reliable and steady. Unless operators act, they risk being sidelined in favor of lower-cost alternatives, accelerating the decline of one of their key income streams.

Flash Calls vs. Traditional Authentication (SMS / Voice OTP)

To appreciate the shift, here’s a comparison:

| Method | Cost to App/OTT | Revenue to Operator | User Experience | Risks / Drawbacks | | ----- | ----- | ----- | ----- | ----- | | SMS-OTP | Moderate-High (cost per SMS, interconnect, possible failed delivery) | Direct A2P SMS revenue; well-established billing & contracts | Widely accepted, fairly reliable; user manually enters OTP (or auto-read on Android) | SMS can be delayed, intercepted, risk of fraud; cost for OTT can be high in some regions | | Voice OTP (answered call or voice message) | Higher (voice termination costs etc.) | Revenue via voice MM/termination; costlier to run | Sometimes slower; user must listen; potential user friction | Call quality issues; cost variability; sometimes fewer users prefer voice receipts | | Flash Call | Lower (since no SMS cost, and the call is not answered / low duration) | Minimal to none if not monetized; high risk of being bypassed / invisible | Very fast; near-zero user action (if app has permissions) | Legal/privacy concerns; platform restrictions; potential fraud/spoofing; good detection needed |

Flash Call Fraud, When “Flash” Becomes Misuse

Not all flash calls are malicious, many are legitimate verification tools. But there are fraudulent or abusive ways this pattern can be used:

• Using flash calls to pretend legitimate verification but actually to phish or scam: tricking users into expecting a missed call, or using spoofed numbers.
• Use of flash call traffic to hide or reduce detection of other voice frauds. For example, blending in with legitimate verification traffic.
• Fraudsters may attempt to artificially generate verification load, generating many flash calls to test or probe network behavior, or to exploit “free” routes.
• Caller-ID (“CLI”) manipulation or “CLI spoofing” or suppression to mislead systems.
• Using flash calls to bypass regional or global SMS blocking / restrictions.

What Telecom Operators Can Do: From Protection to Monetisation

It’s not all bad news, there are clear actions telcos can take to protect revenue, reduce fraud risk, and even turn the flash call trend into a new revenue stream.

1. Detect & Classify Flash Call Traffic

   • Deploy advanced analytics / AI / machine learning tools to monitor voice setup traffic (signaling) for patterns consistent with flash calls.
   • Use voice firewalls and gateway filtering to separate flash call attempts from regular voice or missed calls.
   • Achieve high accuracy, low false positives, misclassifying normal calls hurts customer experience.

2. Real-Time Monitoring & Controls

   • Put in place real-time control over call routing, CLI integrity, detection of whether calls are being auto-terminated before being “answered.”
   • Potentially impose minimal “setup” fees or charges for flash calls, especially from large volume app/OTT providers. This can help offset costs and restore some revenue.

3. Negotiation / Partnership with OTT / App Platforms

   • Create fair interconnect or usage agreements for flash call authentication.
   • Offer “flash authentication as a service” with clear SLAs, transparency, billing models.

4. Regulatory & Legal Compliance

   • Be proactive in understanding national / regional telecom / privacy laws about automated calls, user consent, handling of caller ID metadata, etc.
   • Where needed, push for regulation or standardization (or at least clarity) around flash call authentication.

5. Monétisation Models
   Some ways operators can turn flash calls from a threat into an opportunity:

   • Bill flash call attempts (or set-up charges) to service providers / apps.
   • Offer higher-quality or premium authentication services (incl. flash calls + fallback to SMS/voice) as a value-added service.
   • Use detection systems to redirect suspected flash-call authentication traffic back through SMS or voice when required (e.g. in markets where flash calls aren’t accepted).
   • Bundle authentication as part of an enterprise / 2FA service with clear pricing.

6. Invest in Signaling Infrastructure & Network Capacity

   • Since flash calls do use signalling capacity, ensure signaling infrastructure is properly dimensioned.
   • Monitor network quality (NER, QoS) to ensure flash call volumes don’t degrade other voice or data services.

Business Case: Cost of Inaction

Let’s consider what can happen if operators don’t respond effectively:

• Continual erosion of A2P SMS business. As more services move to flash call based verification, SMS volumes decline, meaning lower revenue, but fixed or rising costs (for maintaining SMSCs, interconnect, etc.).
• Increased fraud / scam risk → customer complaints → reputational damage.
• Regulatory or regulatory environment issues if flash calls cross into being considered spam or unwanted calls (or violating consent/privacy laws).
• Loss of market control. If OTTs or third-party verification providers take over authentication flows entirely, operators may become “dumb pipes” for verification traffic, losing leverage.

Positives: What Gains Are Possible If You Do It Right

• Recover lost or hidden revenue via detection & billing.
• Offer new services to OTT / app providers and enterprises (authentication services), creating diversified revenue streams.
• Improve customer trust if able to guarantee security, limit abuse, reduce spoofing.
• Maintain network quality / customer satisfaction by preventing overload.

Our Deep-Dive Webinar

Want to see this in action, hear from telecom operators who are already tackling flash calls, and see demos of detection & monetization solutions? Check out our webinar:

Flash Calls & Telecom Revenue: Understanding The Threat, Building Defenses, Seizing the Opportunity
🎥 Watch it here: https://youtu.be/OhLvyKOnN6o?list=PLKUH1bM_ymBITLLTObSRLQv4S9ydjEVbu

In the webinar, we cover:

• how detection works (which signals / logs are essential)
• cost/benefit trade-offs
• strategies to negotiate with OTTs & build new revenue streams

What Steps Should Operators Take Now

Here are some actionable steps, phased over short-, medium-, and long-term, for telecom operators.

| Timeframe | Actions | | ----- | ----- | | Immediate (1-3 months) | Audit existing traffic to try to estimate flash calls / verification traffic. Evaluate current SMS OTP volumes & identify declines. Engage internal network / signaling teams to see what logs are available. | | Short-term (3-6 months) | Deploy or enhance detection systems (voice firewall, CLI tracking). Pilot charging or billing models with one or more OTT / app partners. Start conversation with regulators or standardization bodies. | | Medium-term (6-12 months) | Establish formal monetisation plans (e.g., flash call authentication as a service). Introduce policies for consent / transparency to end users. Build infrastructure capacity or optimize networks to handle signalling load. | | Long-term (12+ months) | Standardize flash call authentication channels, possibly collaborate industry-wide. Investigate alternative authentication methods (biometrics, app-based) as backups or complements. Keep monitoring evolving fraud tactics. |

Conclusion

Flash calls are a rising trend because they provide fast, cheap, frictionless verification for apps and OTT services. But for telecom operators, they are a double-edged sword: potential revenue leakage, fraud risk, network and operational strain. The good news is that with proper detection, strategic billing or partnership models, and strong controls, operators can both defend their existing revenue streams and even build new ones around authentication services.

If operators wait, many of the losses are likely to compound. But with the right moves now, there’s a chance not just to limit the damage, but to come out ahead, turning what seems like a threat into a strategic advantage.