What Attachment Types Are Unsafe in Email?

What Attachment Types Are Unsafe in Email?

Unsafe email attachment types include executable files, scripts, and archives containing executables. These file types are commonly blocked by email servers and clients due to security risks including malware, viruses, and potential system compromise.

Understanding which attachment types are unsafe helps avoid delivery issues, security problems, and ensures reliable email communication. Always use safe file types or cloud storage links for file sharing.

Extract and analyze attachments from emails using our extract email attachments tool to identify file types and verify attachment safety.

Executable Files

Executable files are the most dangerous attachment types and are almost always blocked:

Windows Executables

• .exe: Windows executable programs - highest risk
• .bat, .cmd: Batch script files - can execute commands
• .scr: Screen saver files - can contain malware
• .com: Command files - executable programs
• .pif: Program Information Files - can execute programs

Security Risks

Executable files can contain malware, viruses, ransomware, or other malicious code that can compromise systems when opened.

Blocking

Email servers and clients universally block executable files to prevent security threats and malware distribution.

Script Files

Script files can execute code and are commonly blocked:

Script Types

• .js: JavaScript files - can execute malicious code
• .vbs: VBScript files - Windows script execution
• .ps1: PowerShell scripts - powerful system access
• .sh: Shell scripts - Unix/Linux command execution
• .jar: Java archive files - can contain executable code

Security Risks

Scripts can execute commands, access system resources, download malware, or perform other malicious actions.

Blocking

Many email systems block script files to prevent code execution and system compromise.

Archive Files

Archive files may be blocked if they contain executables or are password-protected:

Archive Types

• .zip: ZIP archives - blocked if containing executables
• .rar: RAR archives - blocked if containing executables
• .7z: 7-Zip archives - blocked if containing executables
• Password-protected: Archives with passwords prevent virus scanning

Security Risks

Archives can contain executables or scripts that bypass direct attachment blocking. Password-protected archives prevent virus scanning.

Blocking

Archives containing executables or password-protected archives are often blocked by email security systems.

Safe Alternatives

Safe File Types

Use these commonly accepted file types:

• Documents: .pdf, .docx, .xlsx, .pptx, .txt
• Images: .jpg, .png, .gif, .bmp
• Media: .mp3, .mp4, .wav (check size limits)
• Data: .csv, .json, .xml

Cloud Storage Links

For any file type, especially large files or potentially unsafe types, use cloud storage links:

• Google Drive
• Dropbox
• OneDrive
• SharePoint
• Other cloud storage services

Best Practices

• Never send executable files as attachments
• Use cloud storage for large files
• Scan files for viruses before sending
• Use password protection for sensitive files (via cloud storage)
• Test attachment delivery before important sends