Attachment Checker allows admin to restrict the types of attachment uploaded through File Type Blocking.
The file type blocking consist of the extension check and mime type check.
Extension check is based on the filename of the attachment. For example, if filename is myAttachment.jpg, the extension will be jpg.
Mime type check is based on the contents of the attachment. It prevents the bypass of extension check by renaming or removing the extension.
Apache Tika is used to detect the mime type of the attachment uploaded.
Refer to Supported Document Formats to find out which file types are supported.
Attachments can be filtered based on:
Allowlist → Only file types listed are allowed to be uploaded
Denylist → Only file types listed are blocked from being uploaded
For example, extensions is configured to: jpg, png, gif, svg
Only the following files will be allowed:
jpg, jpeg, jpe, jif, jfif, jfi, png, gif, svg, svgz
For example, extensions is configured to: exe
Only the following files will be blocked:
exe, dll, com
You can use the following list of extensions:
gif, jpg, png, txt, log, xml, doc, docx, xls, xlsx, ppt, pptx, pdf
Images: gif, jpg, png
gif, jpg, png
Text files: txt, log, xml
txt, log, xml
Office documents: doc, docx, xls, xlsx, ppt, pptx, pdf
doc, docx, xls, xlsx, ppt, pptx, pdf
Refer to Which file types are safe for more info.