7. Security Considerations

7. Security Considerations

All form-processing software should treat user supplied form-data with sensitivity, as it often contains confidential or personally identifying information. There is widespread use of form "auto-fill" features in web browsers; these might be used to trick users to unknowingly send confidential information when completing otherwise innocuous tasks. multipart/form-data does not supply any features for checking integrity, ensuring confidentiality, avoiding user confusion, or other security features; those concerns must be addressed by the form-filling and form-data-interpreting applications.

Applications that receive forms and process them must be careful not to supply data back to the requesting form-processing site that was not intended to be sent.

It is important when interpreting the filename of the Content-Disposition header field to not inadvertently overwrite files in the recipient's file space.

User applications that request form information from users must be careful not to cause a user to send information to the requestor or a third party unwillingly or unwittingly.

With the introduction of form-data that can reasonably send back the content of files from a user's file space, the possibility arises that a user might be sent an automated script that fills out a form and then sends one of the user's local files to another address. Thus, additional caution is required when executing automated scripting where form-data might include a user's files.

Files sent via multipart/form-data may contain arbitrary executable content, and precautions against malicious content are necessary. The considerations of Sections 2.3 and 5 of [RFC2183], with respect to the "filename" parameter of the Content-Disposition header field, also apply to its usage here.