You receive a short email about an invoice you don't recognize.
No links. No attachments. Just a few sentences.
A few minutes later, your phone rings.
In the previous posts I described attacks that start with a flood of spam.
This one is different.
There is no spam flood at all. Just a single, harmless-looking email — and a phone call shortly after.
The attack pattern
The email looks like a routine invoice or payment confirmation. The message is short and generic, something like:
- "Please find the attached invoice for services rendered"
- "Your subscription will be renewed in 24 hours"
- "Payment confirmation — please review"
There is nothing to click. Nothing to download. Nothing for security tools to scan or block.
But the victim sees an unfamiliar invoice and starts to wonder:
Did someone use my card? Have I forgotten about a subscription? Is this fraud?
That confusion is the whole point.
The phone call
The caller introduces themselves as someone from IT, customer support, or the billing department. They explain that they have noticed the suspicious invoice email and want to help sort it out.
Because the victim just received exactly such an email, the call feels completely legitimate.
The caller is friendly. Helpful. Professional.
And they ask the victim to start a screen-sharing session — usually through Zoom, Microsoft Teams, or a similar tool — so they can "take a closer look at the problem."
What happens next
Once the screen-sharing session is running, the caller guides the victim through installing a remote support tool.
These are normal programs that IT departments around the world use every day — for example AnyDesk, TeamViewer, Quick Assist, Bomgar, SuperOps, or Zoho Assist. They allow another person to control your computer remotely.
That is exactly what the attacker wants.
The instructions for installing the tool are often shared through a service called privnote.com, which sends notes that delete themselves after being read. This leaves almost no trace.
Once the tool is installed and the attacker has remote control, the real attack begins.
The objective
The goal is almost always the same: steal data, then demand payment.
The attackers search through the computer and connected systems for sensitive files — legal contracts, financial records, personal information, anything that would be damaging if leaked.
The stolen files are copied out of the company, often to the attacker's own server, or simply emailed from the victim's own mailbox.
Within about 30 minutes of leaving the system, the attacker sends an extortion email demanding payment within three days. If the company does not respond, the attackers threaten to contact employees and customers directly, publish the stolen files online, and damage the company's reputation publicly.
In many cases, the entire attack — from the first email to the extortion demand — happens within a single business day.
Why the technique works
The attack works because it targets people, not technology.
A confusing email creates just enough worry that the victim picks up when the phone rings. The caller is calm and helpful. They reference a real email the victim just saw with their own eyes. Everything feels normal.
By the time anything looks wrong, the attacker is already inside.
How to reduce the risk
This kind of attack is difficult to stop with technology alone. The most important defenses are human:
- IT and support staff should never contact users about unexpected invoices or billing issues out of the blue. If you receive such a call, hang up and call back through a known internal number.
- Be skeptical of anyone who asks you to install remote-control software, even if they sound official.
- Remote-control tools like AnyDesk, TeamViewer, and Quick Assist should be limited or blocked on company computers unless they are actually needed.
Industries that handle sensitive client data — law firms, financial services, insurance, and healthcare — are especially attractive targets. The combination of valuable files and pressure to avoid bad publicity makes them more likely to pay quickly and quietly.
The pattern across all these posts
Across this series I have described several variations of the same idea:
- Spam flood + fake IT support on Teams
- Spam flood + fake support on social media
- Spam flood used to hide an important security email
- A fake invoice email + a phone call
The channel changes. The story changes. The pretext changes.
But the core technique is always the same:
Create a problem → Offer to help → Gain access.
