Why is it important?
An inadvertent screenshot can lead to:
- the disclosure of personal data (e.g., names, addresses, phone numbers) in open channels,
- the public release of sensitive company information: rates, budgets, project plans,
- a permanent trace in systems (Teams/Slack/SharePoint), backups, and emails – difficult to "retract",
- rapid dissemination (forward, repost) and the obligation to report a breach.
Real-life example:
Someone uploaded a screenshot of an identity document, "masking" sensitive fields with blurring (Gaussian blur). Another internet user used a free sharpening tool (e.g., Smart Deblur) and recovered part of the text: first name, last name, and fragments of numbers. The rest could be guessed from checksums (e.g., in the document number/PESEL).
What can you do?
Before taking a screenshot:
- Close tabs/windows with data (email, CRM, HR, chats).
- Share only the window, not the entire screen (option in Teams/Meet/Zoom).
- Enable "Do Not Disturb" to hide notifications (a toast from an email can also be a leak).
While taking the screenshot:
- Crop narrowly – show only what is necessary for the matter.
- Check the taskbar and file names to ensure they do not reveal too much.
After taking the screenshot (mandatory!):
- Mask the data: use a redaction/blurring tool (Paint/Photos/Preview has drawing functions; in PowerPoint/Keynote, use a rectangle + fill; in Snipping Tool/Shot/Monosnap – "redact").
- Check the metadata: images may contain the username or location – remove properties before sending ("Properties → Details → Remove Properties").
- Save as a new file (without version history), and delete the original from the Recycle Bin.
Tool tips:
- Windows: Win+Shift+S (screenshot), Snipping Tool (edit and redact).
- macOS: Cmd+Shift+4 (crop), Preview (annotation tools → filled rectangle).
- Browser: "full page screenshot" extensions only when it does not contain sensitive data below the visible area.
- Blurring: "redact/blur" instead of drawing with a thin line (text underneath may be readable).
Remember!
A screenshot is like a photo of your desk: if other people's documents are lying on it, everyone will see them. First, tidy up, then take the picture.
Consciously taking screenshots is a quick habit that saves time, nerves, and breach reports – start applying it from today.
