What is vishing?
Vishing is a word that merges “voice” and “phishing.” It is a type of phishing in which cybercriminals use phone calls (and possibly also voice technology) to manipulate victims into divulging sensitive information.
Unlike traditional email phishing, vishing exploits the psychological circumstances of a real-time conversation to build trust and create a sense of urgency. The process often involves caller ID spoofing, making scam calls appear to originate from legitimate sources such as banks, government agencies, or trusted companies. This technological deception, combined with skilled social engineering, creates a potentially powerful tool for attackers.
Common vishing targets include individuals with financial accounts, employees with company credentials, and anyone who might possess valuable personal information. These attacks can result in identity theft, financial fraud, data breaches, and significant organisational damage.
How vishing attacks work
As a type of social engineering, vishing exploits the trust inherent in human-to-human exchanges. “Social engineering is just human language and human interaction,” explains Luigi Pardey, a security engineer at Fourthline. “There is not necessarily sophisticated technology involved in that.”
Attackers craft persuasive narratives, often posing as legitimate representatives from financial institutions, government agencies, or technology companies. This perceived authority compels victims to comply with requests for sensitive information.
Common vishing techniques include:
Impersonation: Attackers pretend to be trusted officials, bank representatives, or IT support personnel, piggybacking on the authority associated with these roles.
Creating a sense of urgency: Attackers try to create panic by claiming immediate threats to accounts, legal troubles, or security breaches that require instant action.
Pretexting: Attackers create plausible scenarios to justify their requests for information, citing official-sounding reasons such as "account verification" or "security updates."
Reverse vishing: Some attacks convince victims to call back spoofed numbers, adding an extra layer of perceived legitimacy.
These methods leverage basic aspects of human psychology. They’re designed to be easy to fall for, so it’s crucial to stay vigilant — regardless of how legitimate a caller may sound.
Caller ID spoofing and social engineering
Caller ID spoofing serves as the technical foundation for most vishing attacks. By displaying familiar or authoritative phone numbers on the victim’s phones (rather than the true source number of the call), scammers immediately establish a baseline of trust before the conversation even begins.
The combination of a spoofed caller ID with social engineering creates a powerful deception. Attackers use emotional manipulation, authority claims, and urgency tactics to override victims' natural scepticism.
The psychology of voice-based trust
Voice communication carries an inherent sense of immediacy and authenticity that attackers systematically exploit. The real-time nature of phone conversations makes it difficult for victims to pause and verify information, while the human voice carries emotional weight that text-based communications lack.
"It just makes you as a victim more trusting of the person trying to perpetrate the attack,” says Pardey.
Still, it's important to remember that the basic psychology is the same regardless of whether the attacker is using a phone call, SMS, or some other technology. “These are just tools to give the attacker more of an upper hand in gaining your trust.”
This psychological advantage becomes even more pronounced when enhanced with technologies like AI-generated voices, creating a compounding effect that makes detection increasingly difficult.
AI-generated voices: An emerging threat?
One of the most concerning developments in vishing is the emergence of voice synthesis, which Pardey defines as "the ability to generate convincing audio that mimics a real person’s voice patterns.”
Such tactics stand a good chance of fooling many people, though Pardey and other security experts note that they still face significant practical limitations that prevent them from becoming widespread.
For one, voice synthesis “is not as easy to perpetrate on a specific individual that is not publicly known,” says Pardey. “If you want to make a synthetic voice, you have to have voice data from whoever you're trying to impersonate."
This requirement for substantial voice data creates a natural barrier that — for now — limits the scalability of sophisticated voice synthesis, particularly when it involves the voices of private individuals who don't have extensive public voice recordings available.
Despite advancing AI technology and the potential for sophisticated voice synthesis, many attackers still rely on basic methods. Such methods tend to come ahead in terms of the cost-benefit analysis for a particular attack, as they are relatively inexpensive and can reach a vast number of potential victims.
Common types of vishing scams
Vishing scams are not limited to a specific industry or sector. Attackers have attempted to use vishing for many purposes, including:
Banking fraud: Attackers pose as bank representatives, claiming urgent security issues with accounts. They request verification of account details, PINs, or passwords under the false pretence of protecting the victim's finances.
Tax season scams: Attackers impersonate tax officials, threatening legal action for supposed unpaid taxes. These scams exploit fear of government authority and potential legal consequences.
Tech support scams: Attackers claim to be IT professionals, informing victims of malware infections or security breaches. Then, they request remote access to devices or payment for fake solutions.
Charity scams: Attackers exploit goodwill by posing as representatives of legitimate charities, particularly during disaster relief efforts or major events.
Corporate impersonation: Attackers target employees by impersonating executives or IT departments, requesting login credentials or financial transactions.
How to prevent successful vishing attacks
There are a few best practices to help minimise the risks of vishing and other social engineering attacks, both on the individual and organisational level.
What individuals can do
Never provide sensitive information over unsolicited calls
Verify caller identity through independent channels, such as email or an office messaging platform
Be suspicious of urgent requests or pressure tactics
Hang up and call official numbers to verify legitimate requests
Use strong, unique passwords and enable multi-factor authentication
What organisations can do
Implement robust identity verification protocols
Conduct regular employee trainings
Establish clear communication channels for sensitive requests
Deploy advanced call filtering and monitoring systems
Create incident response procedures for suspected attacks
"The attacks that will likely get you are the ones that are basic,” says Pardey. This may sound surprising, given the focus on advanced scamming technologies in the media, but it underscores the importance of maintaining fundamental security practices even as sophisticated technologies emerge.
Building a security-aware organisational culture
Effective vishing prevention demands more than technology — it demands a culture of security awareness.
Organisations should host regular training sessions on emerging threats while sharing real-world examples of vishing attempts to help employees recognize potential attacks. Encouraging employees to report suspicious calls creates an environment where security concerns can be addressed promptly, and rewarding proactive security behaviours reinforces the importance of vigilance.
Maintaining open communication about security concerns ensures that everyone understands their role in keeping the business safe.
The future of vishing threats
As technology continues to evolve, vishing attacks will likely become more sophisticated — even as they remain fundamentally dependent on human psychology. AI-generated voices, deepfake technology, and advanced social engineering techniques will emerge, but the core principles of verification, scepticism, and security awareness will remain essential to a good defence.
The key to staying ahead of vishing threats lies not just in adopting the latest security technologies, but in building an organisational environment where every employee is empowered with the knowledge to head off threats at the source.
This article incorporates insights from Luigi Pardey, a Security Engineer at Fourthline. It is for informational purposes only and does not constitute legal advice.
