Impersonation Fraud Protection: A Guide for Banks and Enterprises

Impersonation fraud is one of the fastest-growing threats facing banks, enterprises, and their customers. From fake fraud team calls to spoofed SMS alerts, criminals now exploit trusted brand identities to deceive users, often with devastating consequences. While attacks may use email, social media apps, and other channels, we will focus on impersonation attacks that employ scam calls and SMS. In this guide, we break down how impersonation fraud works in telecom, the tactics used, why it’s so hard to detect, and most importantly: what banks, enterprises, operators, and regulators can do to prevent these scams.

Impersonation fraud exploits public trust by mimicking communications from trusted brands; banks, delivery services, or government agencies. Victims receive calls or messages that appear genuine and are tricked into taking harmful actions.

What makes this fraud especially dangerous is its simplicity: attackers don’t need to breach enterprise systems, they only need access to telecom networks and a convincing script. The result is financial loss, reputational damage, and legal risk for the impersonated brand.

Attackers manipulate telecom protocols to spoof caller IDs or SMS sender names, inserting fake messages into real threads or displaying trusted numbers. Most users can’t tell the difference.

These attacks also rely on psychological pressure. Victims are pushed to act urgently—“verify identity,” “avoid suspension,” “confirm a payment.” AI-generated voices, cloned websites, and leaked data boost the scam’s credibility and success rate.

CLI (Calling Line Identification) spoofing lets fraudsters fake a caller ID, making a call or message appear to come from a trusted source: a bank, government agency, or support line.

Spoofing exploits gaps in global telecom protocols. Attackers hijack your phone number or SMS sender ID to impersonate your brand—without touching your systems. On the customer’s screen, the call or message looks completely legitimate, making it very hard to detect or block.

Fraudsters impersonate your brand to target customers, staff, or vendors—without breaching your systems.

Common methods:

• Fake anti-fraud team calls about suspicious transactions
• SMS alerts linking to phishing sites
• CEO payment scams (Business Email Compromise)
• Know Your Customer/IT support requests to install malware

Targeted sectors:

• Banking: Spoofed anti-fraud calls and urgent SMS alerts
• E-commerce and logistics: Fake delivery messages with phishing links
• Healthcare: Fraudulent appointment reminders or portal access requests
• Government: Impersonation of officials, fake fines, or benefit scams

These attacks succeed because they appear legitimate. Victims believe they’re engaging with real customer service agents or trusted portals. When the truth emerges, it damages trust, risks customer loss, and exposes brands—especially in regulated industries—to legal and financial liability.

Smishing (SMS phishing) and vishing (voice phishing) are two of the most common and damaging forms of impersonation fraud.

Smishing uses fake SMS messages that appear to come from trusted brands. Victims are prompted to click links or verify details urgently—often leading to phishing sites that steal sensitive information like card numbers or login credentials.

Vishing is the voice equivalent. Scammers call while posing as bank staff or officials, using spoofed numbers to appear legitimate. Victims are pressured into revealing personal data or making payments to fraudulent accounts.

Impersonation fraud happens daily, exploiting brand confidence and emotional urgency. Here are two real-world examples:

Case 1: Bank of Ireland “Safe Account” Scam

In 2025, customers received spoofed SMS messages inserted into genuine bank threads, urging them to call and transfer funds to “safe accounts.”

Why it worked:

• Spoofed SMS appeared in legitimate Bank message threads
• Creation of an urgent situation, authoritative and convincing tone 
• Avoided typical scam red flags (e.g., attempts to gain account access)

The scam reached 80% of the population and triggered a tenfold surge in fraud reports within 24 hours, too fast for banks to respond effectively.

Case 2: NAB Spoofed Vishing Scam in Australia 

A Melbourne resident received a spoofed call and follow-up SMS from what appeared to be NAB. Told her card was compromised, she was persuaded to transfer AU$39,000 to a “safe” account. 

Why it worked: 

• Caller ID and sender ID matched NAB’s real numbers
• Urgent tone pressured immediate action 
• Victim kept on the phone for over an hour, leaving no time to verify independently

The case highlights how easily scammers can exploit telecom weaknesses and the difficulty for victims to recover losses or receive timely support.

Impersonation fraud is escalating fast, especially through voice and SMS channels.

Global Trends (GLF, GASA, FTC)

• Smishing is the #1 scam method in countries like the Philippines (86%), South Korea (85%), Kenya (84%), and Brazil (82%).
• Voice-based scams dominate in Thailand, Russia, and Hong Kong.
• Email is now the top scam vector in the US (2024).
• South Africa, Ethiopia, Palestine, Germany, Spain,  all report high levels of spoofing and smishing.

AI-enabled scams are rising fast (GASA):

• 76% know AI can write scam texts.
• 66% aware of AI voice cloning risks.
• 31% of scam victims couldn’t tell if AI was used.

Financial Damages

• In the US, median losses reached $14,740 for cash payments in 2024, with similar figures for crypto and bank transfers.
• In the UK, the average user loss per impersonation case was £7,448 in 2023.

Reputational Harm

• Brand trust suffers when fraudsters exploit familiar names. In recent cases, from the 2025 Bank of Ireland spoofing attack to fake UPS delivery texts, many blame the brand and voice frustration online.
• According to GASA, only 9% of impersonation victims were informed through official channels in 2024. Silence from brands often worsens the fallout as users rely on peers, not providers, for support.

Regulatory and Legal Consequences

• In the US, the FTC can impose fines of up to $53,088 per violation under new impersonation fraud rules.
• 93% of fintech C-suite leaders say regulatory penalties and reputational damage are their top concerns, outranking direct financial losses (87%) and customer loss (87%).

In late 2024, the UK’s Payment Systems Regulator (PSR) introduced mandatory reimbursement rules for APP scam victims, requiring both sending and receiving providers to cover 50% of losses.

Four key factors are driving the rise in impersonation fraud:

• AI-generated voices and deepfakes make scam calls sound convincing. Voice cloning and synthetic text tools now let fraudsters impersonate brand agents or internal staff.
• There is no global system for real-time spoofing detection. Most operators lack cross-network call validation, allowing fake calls and messages to slip through, especially when traffic passes between networks or countries. Telecom technologies from 2G to 4G were not designed with built-in security or authentication, and even 5G inherits many vulnerabilities from these legacy networks.
• VoIP and VoLTE enable global spoofing at scale. While many calls still travel over legacy 2G/3G networks, newer IP-based technologies like VoIP and VoLTE use protocols such as SIP (Session Initiation Protocol), which are easier to manipulate than older systems. This makes it simpler and cheaper for attackers with little specialized knowledge of telecom protocols to access and spoof caller IDs.

Fraud calls exploit network loopholes such as international roaming and grey routes to bypass country-specific safeguards and deliver scam traffic across jurisdictions. Using a mix of roaming, unregulated transit, and spoofing to disguise scam calls, fraudsters route them through “clean” or hard-to-regulate paths, making them harder to detect, block, or trace, especially when they cross international borders. Billing delays between international networks work to the attackers’ advantage, as they also delay the detection of fraud.

Caller ID spoofing isn’t always illegal. Many legitimate businesses like call centers use it to display a central support number for consistency and trust. In places like the U.S., spoofing only becomes unlawful when it’s used “with the intent to defraud, cause harm, or wrongfully obtain anything of value,” under the Truth in Caller ID Act.

The same act allows fines for malicious spoofing, and the FCC’s STIR/SHAKEN framework authenticates IP-based calls. But it doesn’t cover international or non-IP traffic, such as calls over legacy 2G/3G networks where authentication data is lost. To address this gap, the FCC has issued a Notice of Proposed Rulemaking to mandate non-IP caller ID authentication solutions. AB Handshake has been formally cited as a potential framework under evaluation, offering real-time, out-of-band call validation that works even where STIR/SHAKEN cannot.

In the UK, Ofcom now requires providers to block spoofed UK fixed-line numbers from abroad and is reviewing broader protections. Globally, regulation is inconsistent. Most countries lack mandatory validation systems, leaving exploitable gaps. 

Solving this requires the active participation of all key stakeholders: regulators, operators, and enterprises. Regulator-led national frameworks with enforced traffic validation are key to lasting protection.

Most solutions depend on individual telecom operators—but no single provider sees the full picture. International working groups and industry associations, such as the GSMA, provide standards and recommend best practices, but the industry lacks mechanisms to affect widespread adoption. 

Spoofing Detection requires Data Sharing: Numbers are most commonly spoofed from abroad. This means that fraudsters in other countries send messages and place international calls to victims in the target country, spoofing the CLI to come from a local number. 

One of the most logical ways to detect if the call or message is spoofed is to verify whether the device associated with the number is indeed roaming abroad. Each operator can easily verify whether their own subscribers are roaming or not; however, they do not have access to the roaming status of subscribers of other local (competing) networks. This means that they are unable to verify if an international call from a number belonging to any network besides their own is even roaming, much less legitimate. 

Few countries have frameworks in place to enable this kind of data sharing among national operators. For the same reason, operators lack frameworks and incentives to share information that would allow them to verify the validity of caller and sender IDs. 

Infrastructure isn’t built to detect spoofing: Voice and SMS protocols were never designed to authenticate sender/caller identity. This makes it easy to fake Caller IDs or SMS headers, especially across international routes.

Operators often lack effective fraud controls: Many carriers, particularly smaller ones, don’t have real-time detection, analytics, or blocking capabilities, leaving blind spots that scammers exploit.

No cross-network visibility: Fraud travels easily between networks, but defences remain siloed. When attacks are blocked by one network, fraudsters simply target victims on another.

Consumers are expected to spot scams: Most defenses rely on user awareness campaigns, but brand-imitating scams are often indistinguishable—placing too much pressure on individuals.

Enterprises and telcos rarely share fraud data: When fraudsters impersonate brands, those brands often have no direct channel to alert telecom providers. This lack of coordination slows down response times, allowing spoofed numbers to remain in use longer than necessary.

Caller authentication tools—such as branded calling and verified sender registries (e.g., Google Verified Calls)—aim to display a brand’s name, logo, and call reason on the recipient’s screen. However, branded calling is not a deterrent against spoofing, as it lacks authentication mechanisms. Spoofed calls may be delivered without branding or may be tampered with to include branding, further legitimizing the fraudulent call’s appearance. RCS is seeing increased adoption; however, there is no unified fraud prevention for RCS, and fraudsters are actively exploiting the gaps in this protocol.

Verified sender registries can help reduce spoofing and scam traffic. However, calls and messages routed internationally may bypass verification checks, allowing fraudulent traffic to reach users.

Number reputation systems and scam labeling tools flag suspicious numbers, yet they do little to address spoofing. Calls and messages labeled with warnings are typically based on databases of known fraudulent numbers and invalid numbers. Spoofed traffic frequently uses valid numbers and therefore easily bypasses these protections. By failing to label spoofed calls, the fraudulent call appears to be even more legitimate.

SMS firewalls and content filters block known phishing links and detect suspicious language in messages. However, these tools are largely unable to detect and block spoofed sender IDs. Attackers also bypass detection using AI-generated text and short-lived domains.

Some defenses are implemented within enterprises themselves, including internal training and incident response protocols to fraud reporting systems and customer alerts. While valuable for managing fallout, these tools do not prevent spoofed traffic from reaching users in the first place. 

STIR/SHAKEN is a moderately effective response to caller ID spoofing. It authenticates voice calls over IP-based telecom networks (4G/5G) to help verify legitimacy. However, the protocol does not cover calls on 2G/3G networks or SMS traffic and is not expected to be adopted in many markets. International and cross-network traffic also falls outside its scope, limiting its effectiveness.

Regulation tends to focus on penalties after fraud is reported, rather than on coordinated, preventive action. While punitive measures can incentivize operators to detect and block fraud, enforcement often relies on consumer complaints and complex legal frameworks.

Enterprises are frequent targets but can’t control how their numbers are used across networks. Only telecom operators can verify message origins and block or flag suspicious traffic—but stopping spoofing requires real-time coordination across all national networks within a country.

That coordination doesn’t always happen voluntarily. Operators focus on protecting their own subscriber data and privacy, but spoofing often exploits number ranges from other networks— and no operator can stop their own numbers from being spoofed elsewhere. Without cooperation, operators are largely unable to detect and prevent spoofing and impersonation..

Stopping impersonation fraud at scale requires national coordination—but competing operators lack incentives to cooperate and seldom manage to work together on their own. Regulators are best placed to enable cross-carrier collaboration that respects privacy and competition. Collective solutions, such as real-time inter-operator validation systems are most effective under a central, trusted authority. Together, regulators, operators, and enterprises can build shared protections that block spoofed traffic before it reaches users.

You don’t need to solve the problem alone, but you do need to act. Moving away from calls and SMS as part of customer outreach isn’t the answer. These channels remain among the most effective ways to reach and serve customers. Even if you are not sending SMS messages or calling your customers, that will not stop scammers from impersonating your brand and defrauding your customers on these channels. Moving to other channels only leaves the telecom space open for scammers to take over your brand identity unchecked, eroding trust and damaging your reputation.

Start here:

• Report spoofing and fraud incidents to your telecom partners and verified reporting services and encourage them to take action.
• Participate in DNO lists, verified caller registries, and Sender ID controls and work with messaging vendors that support identity validation tools. Programs such as the MEF SMS Sender ID Protection Registry (the UK SMS Sender ID Registry) and frameworks promoted by the GSMA help authenticate your sender identity and reduce spoofing risks at the network level. Many messaging vendors support identity validation tools. 

! These tools may prevent your official numbers from being used in spoofing, but they don’t stop fraud outright. Because these databases are publicly accessible, scammers can simply choose alternative or lookalike numbers to impersonate your brand.

Go further:

• Partner with national operators to implement out-of-band validation:
  • Tools like AB Call Validation and AB SMS Security confirm that a call or message genuinely came from your brand by comparing sender details between the originating entity and terminating operator in real time, blocking spoofed traffic before it reaches the user.
  • These solutions protect all subscribers on a participating network and provide a proven model for broader rollout.
  • Operators also benefit, as fraud damages their revenue and reputation as well. These tools block various other fraud types that impact the operators themselves. 
    
     
• Support solutions that validate traffic on a national level:
  • Platforms like the National Anti-Fraud Platform (NAFP) enable real-time verification of voice and SMS traffic, cross-checking call and message data between originating and terminating networks. This helps regulators prevent spoofing, impersonation, and illegal number use before delivery. Centralized solutions allow various stakeholders, including enterprise, operators, and regulators, to effectively collaborate to tackle spoofing at the national level, protecting citizens, businesses, and service providers alike.

Besides brand spoofing, criminals exploit telecom and network infrastructure in other attacks that are damaging to businesses: generating fake SMS traffic, hijacking your PBX, or triggering costly callbacks. Unlike impersonation, solutions to these fraud types can be deployed locally without reliance on the service provider.

Here are three common threats:

PBX Hacking

PBX hacking exploits vulnerabilities in business phone systems, making and rerouting outbound calls to premium-rate international numbers, billed to the victim enterprise. 

Wangiri 2.0

Wangiri 2.0 targets businesses by flooding web forms with fake inquiries, triggering calls to premium-rate phone numbers. When customer service systems call to respond, the company is charged high fees.

Artificial Inflation of Traffic (AIT)

Bots trigger massive volumes of SMS OTPs and alerts to fake users. Some enterprises unknowingly waste over 50% of their SMS spend on this invisible, fraudulent traffic.

AI Shield blocks all three.

Trained on vast volumes of global voice and SMS traffic, AI Shield uses advanced machine learning to detect suspicious patterns with 99.995% accuracy — before damage is done. It offers:

• Real-time blocking and alerts with zero rerouting
• Custom rule-setting and dashboards for full visibility and control
• Flexible deployment: cloud or on-premise, fast and secure

With AI Shield, enterprises get proactive, precision fraud prevention from Day 1 — without adding operational complexity.

Impersonation fraud is one of the most damaging threats in digital communication. It exposes enterprises to financial loss, reputational harm, and legal risk, all without touching your systems– your name alone can be weaponized.

Prevention establishes confidence, reduces fraud costs, ensures message delivery, and protects your brand’s credibility. Voice and SMS remain among the most trusted ways to reach customers. And with proper validation, they can be secured in real time, at scale.

But no one can tackle this alone. Real protection requires a collaborative ecosystem: regulators, operators, and enterprises working together on comprehensive fraud prevention strategies. Only this level of coordination can stop spoofing and traffic manipulation before they reach end users.

Trust in communication isn’t just about compliance; it’s key to lasting customer connection. Businesses that lead on fraud protection don’t just avoid risk; they earn loyalty, resilience, and a competitive edge in any market.

Contact us to learn more about joining our fraud-free community.