Are .ai Files Safe?

TL;DR

Yes, Adobe Illustrator (.ai) files can be malicious. They can contain embedded code that runs when opened, potentially harming your computer or stealing data. Treat them with the same caution as other executable file types.

How .ai Files Can Be Harmful

While less common than threats delivered via documents like Word files (.doc) or PDFs, .ai files have been used in targeted attacks. Here’s how:

• JavaScript: .ai files can contain embedded JavaScript code. When you open the file in Illustrator, this code can execute.
• Object Linking and Embedding (OLE): OLE allows embedding other types of objects within an .ai file. A malicious object could be hidden inside.
• File Format Exploits: Vulnerabilities in how Illustrator processes the .ai format itself can be exploited by specially crafted files.

Steps to Stay Safe

1. Keep Illustrator Updated: Adobe regularly releases updates that patch security vulnerabilities. Always install the latest version.

   You can check for updates within Illustrator itself (Help > Check for Updates).

2. Be Wary of Unknown Sources: Only open .ai files from people or organisations you trust. Avoid opening files received as unsolicited email attachments, downloaded from suspicious websites, or shared via untrusted channels.
   • If you’re expecting an .ai file, confirm with the sender before opening it.
3. Scan Files Before Opening: Use a reputable antivirus program to scan any .ai files before you open them. This can detect known malware.

   Most modern antivirus programs will automatically scan downloaded files, but it’s good practice to manually scan anything suspicious.

4. Sandbox or Virtual Machine: For high-risk files (e.g., from an unknown source), consider opening them in a sandbox environment or virtual machine.

   A sandbox isolates the file from your main system, preventing it from causing harm if it’s malicious.

5. Disable JavaScript Execution (Advanced): If you rarely need JavaScript functionality in Illustrator, you can disable it to reduce risk. Be aware this may break some features of certain .ai files.

   // This is a complex setting and varies by Illustrator version. Search Adobe's documentation for "JavaScript security settings" or similar terms.  It usually involves editing preferences within Illustrator itself.

6. Examine File Properties (Limited Help): While not foolproof, you can check the file properties for unusual information.
   • Right-click on the .ai file and select “Properties” (Windows) or “Get Info” (macOS).
   • Look at the creation date, modification date, and size. Anything drastically out of place could be a red flag.

What to Do If You Suspect a Malicious File

1. Disconnect from the Network: Immediately disconnect your computer from the internet and any network connections to prevent further spread of potential malware.
2. Run a Full System Scan: Perform a full system scan with your antivirus program.
3. Report the Incident: If you believe you’ve been targeted by an attack, report it to your IT department or relevant cybersecurity authorities.