Why scammers call you and say nothing - and how to respond safely

2026-02-26 · Source: News and Advice on the World's Latest Innovations | ZDNET · Field: Technology & Digital — Cybersecurity & Data Privacy · Depth: Fundamental Awareness, short

Summary

Silent calls from unknown numbers are a common scam tactic designed to confirm a phone number's activity and identify it as spammable, according to Shane Barney, CISO at Keeper Security. These automated reconnaissance events validate that a number is owned by a real person before scammers invest human effort. Verified contact data is valuable in modern fraud ecosystems, bought and sold for future attacks like phishing, email scams, password reset triggers, or SIM swap fraud. Calls with a short delay before a response typically indicate a predictive dialing system routing to a live operator, maximizing scammer efficiency. This tactic, though prevalent years ago, has resurfaced, highlighting attackers' tendency to reuse effective techniques.

Key takeaway

For IT professionals and general users concerned about phone scams, understanding the mechanics of silent calls is crucial. If you answer an unknown number and hear silence, hang up immediately or remain silent to potentially flag your number as inactive. Implement robust spam call filtering solutions, whether carrier-provided or third-party apps like RoboKiller, Truecaller, or Hiya, to proactively manage and block these reconnaissance attempts and prevent more serious follow-on attacks.

Key insights

Silent scam calls validate active phone numbers for future fraud operations.

Principles

• Fraud operations scale industrially.
• Verified contact data has market value.
• Attackers reuse effective tactics.

Method

Scammers use automated reconnaissance (silent calls) to filter dormant numbers from reachable individuals, then route active numbers to human operators via predictive dialing systems for follow-on attacks.

In practice

• Hang up on silent unknown calls.
• Stay silent if answering unknown numbers.
• Utilize spam filtering apps/services.

Topics

• Scam Calls
• Phone Fraud
• Spam Filtering
• Cybersecurity
• Predictive Dialing

Best for: General Interest, IT Professional, Security Engineer

Related on AIssential

• Truecaller now lets you hang up on scammers — on behalf of your family — Truecaller's Family Protection feature enables group admins to monitor and intervene in family members' potential scam calls.
• There’s a Scam-Scanning App Inside ChatGPT — Malwarebytes now offers direct scam detection within ChatGPT, enhancing user protection against evolving digital threats.
• Our latest fraud and scams advisory — Online scams are evolving rapidly, employing sophisticated technical bypasses and social engineering to exploit users for financial gain.
• Byoky: Share your AI budget without sharing your keys Discussion | Link — The provided content describes a security verification process for the website "www.producthunt.com".
• What we learned about TEE security from auditing WhatsApp's Private Inference — TEEs offer strong isolation, but secure deployment demands rigorous attention to implementation details, especially input validation and attestation integrity.
• NomNak — Websites use security services to protect against bots and ensure legitimate user access.

Open in AIssential →

Editorial summary, takeaway, and curation by AIssential. Original article published by News and Advice on the World's Latest Innovations | ZDNET.