Microsoft, Apple and Linux are constantly protecting their operating systems against hackers and cyber criminals. They do so by issuing updates. They do not release any updates for their outdated systems anymore, which makes these systems vulnerable. It means that viruses and hackers can easily enter your computer and the university network, even if you have an anti-virus programme installed.

Up-to-date operating system

To protect yourself and the university, it is very important to make sure, for all your devices:

1. that you work with Windows 11 / MacOS 13 or a newer operating system. 
2. that you install the latest security updates.

Is your operating system not up-to-date?

Are you working with Windows 10 or an older operating system? From October 2025 Microsoft will no longer provide free software updates, technical support or security patches for Windows 10. This means you may no longer log on to the university network with Windows 10 (or older). Make sure you upgrade to Windows 11 as soon as possible.

• Do you have an ISSC-managed university laptop with an outdated operating system?
  • To avoid your laptop being blocked, make an appointment today for the upgrade of your laptop via this form: ISSC Windows 11 migratie / Windows 11 migration.
  • See also: Leiden University is upgrading to Windows 11: what will this mean for you?
• Do you have an ISSC-managed university desktop with an outdated operating system? Please notify your ICT-contact person immediately.
  • Make sure that you take all preparatory steps before the upgrade: see Leiden University is upgrading to Windows 11: what will this mean for you?
• Do you work with a self-managed laptop or desktop, or with a personal PC? Then you are personally responsible for the installation of Windows 11. For more information, go to End of support for Windows 10, Windows 8.1, and Windows 7 | Microsoft Windows.

If you can use a Wifi network without a password, then the network is not secure and you are not allowed to use it for your work. What should you do if you DO wish to connect to the internet?

Secure your home network

If you are not using the University’s eduroam network, make sure your connection is secure. Give your home router a strong password, or use your own mobile hotspot (4G/5G data bundle). 

On the Strong passwords page, you can find tips for creating strong passwords.

Public networks are not secure unless you connect via a VPN (Virtual Private Network). Leiden University offers you eduVPN for connecting to the internet on a public Wi-Fi network. EduVPN is already installed on your Windows 11 work laptop. Learn more about secure connections on Tools and tips for working securely online.

You can also use eduVPN on your personal laptop desktop or phone. Watch the instruction video on how to install eduVPN.

Install the latest software updates on all your own devices. If outdated versions of programmes are running on your computer, hackers or other malicious intruders can use these for a cyber attack. Therefore, be sure to update your programmes at least once a month.

ISSC work laptop

Do you have a laptop issued by the university? The updates will be installed when your Windows 11 laptop is connected to the internet.

Save files to your personal OneDrive. To share files with others, use OneDrive, Teams or otherwise SURFdrive. On the page Sharing and sending files, you will find information on using OneDrive, SURFdrive and SURFfilesender.

Learn more about safely sharing and saving files in Teams.

Always lock your workstation

Lock your workstation. To do so on a Windows computer, use the following keyboard shortcut: Windows + L(ock). Make a habit of this, regardless whether you are working from home or at the office. 

Online meetings, calls and chats: use Teams

Use recommended solutions such as Microsoft Teams. Be extra alert if external parties are participating in or hosting an online meeting. Do not share confidential information in online meetings or chats.

Read here about who has access to the information in a Team: Is my Team public or private?

Don't use Whatsapp and preferably not Signal either

Where possible, use Teams to chat with colleagues. It is possible to use Signal, but this is not recommended. The use of WhatsApp for work is not permitted. For more information, see the Tool picker.

Hackers can attack in various ways. Via email or phone you can be asked to share personal information. Be vigilant about phishing. The page about phishing gives you tips on recognising suspect emails and reporting them.

Report any (possible) phishing, data breach or malware to the ISSC Helpdesk (+31 71 527 8888). See also KI 2999 in the helpdesk portal.

Always send work e-mails using your University account, and not via other services such as Gmail or Hotmail. 

Set your cookie settings in your browser to ‘only accept functional cookies.’ Activate the setting that ensures you have to grant sites permission to use cookies.

For detailed information and tips, go to the page Tools and tips for working securely online.