TL;DR
Generally, email services shouldn’t upload files from your computer without your explicit permission (like clicking an ‘Upload’ button). However, vulnerabilities and malicious attachments can sometimes cause unwanted uploads. We’ll cover how this could happen, what protections are in place, and how to stay safe.
Understanding How Email Services Handle Files
Email services like Gmail, Outlook, and Yahoo Mail primarily receive files as attachments. They don’t actively scan your computer for files to upload unless you initiate the process. Here’s a breakdown:
- Attachments: When you receive an email with an attachment, the file is downloaded (or previewed) when you open it.
- Upload Features: Many services have features like Google Drive integration or direct upload buttons for sharing files. These require your deliberate action.
- Links to Cloud Storage: Emails often contain links to files stored on cloud storage platforms (Dropbox, OneDrive etc.). Clicking these downloads the file from that service, not directly from your email provider.
How Unwanted Uploads Could Happen
While rare, here are scenarios where an email service might appear to upload files without direct permission:
- Malicious Attachments: A cleverly crafted attachment (e.g., a Word document with macros) could contain code that attempts to access and upload files in the background. This is a form of malware.
- Compromised Account: If your email account is hacked, an attacker could use it to send emails containing malicious links or attachments, or even directly access connected services (like Google Drive) and upload files.
- Browser Extensions/Add-ons: A rogue browser extension could intercept email content and attempt unauthorized uploads.
- Vulnerabilities in Email Service Software: Although uncommon, bugs in the email service’s software itself could be exploited to allow remote file access or upload.
Protecting Yourself – Step-by-Step Guide
- Be Wary of Attachments: Never open attachments from unknown senders. Even if the sender seems familiar, be cautious if the email is unexpected or contains suspicious content.
- Disable Macros in Office Documents: Macros can execute code automatically. In Microsoft Word (and other Office apps), go to File > Options > Trust Center > Trust Center Settings… and disable all macros with notification. This forces you to approve them before they run.
File > Options > Trust Center > Trust Center Settings... > Macro Settings > Disable all macros with notification - Scan Attachments: Before opening any attachment, scan it with a reputable antivirus program. Most modern antivirus solutions will automatically do this.
- Enable Two-Factor Authentication (2FA): 2FA adds an extra layer of security to your email account. Even if someone gets your password, they’ll need a code from your phone or another device to log in. Check your email provider’s settings for 2FA options.
- Review Connected Apps: Regularly check which apps have access to your email account (e.g., Google Account Activity). Remove any you don’t recognize or no longer use.
Go to your email provider's security settings > Third-party apps with access - Keep Your Software Updated: Ensure your operating system, browser, and antivirus software are always up-to-date. Updates often include security patches that fix vulnerabilities.
- Use a Strong Password: Choose a strong, unique password for your email account. A password manager can help you create and store complex passwords securely.
- Be Careful with Browser Extensions: Only install browser extensions from trusted sources. Review the permissions requested by each extension before installing it.
- Check Email Service Security Settings: Familiarize yourself with your email provider’s security settings and enable any available features that enhance protection (e.g., phishing filters, suspicious activity alerts).
What if You Suspect an Unauthorized Upload?
- Change Your Password Immediately: If you believe your account has been compromised, change your password right away.
- Review Account Activity: Check your email provider’s activity log for any suspicious logins or actions (e.g., sent emails, file access).
- Scan Your Computer for Malware: Run a full system scan with your antivirus program to detect and remove any potential malware.
- Contact Your Email Provider: Report the incident to your email provider’s support team. They may be able to assist you in securing your account and investigating the issue.
cyber security Resources
- NCSC (National Cyber Security Centre): https://www.ncsc.gov.uk
- Stay Safe Online: https://staysafeonline.org/