Setting Appropriate Security

SA-FileUp executes in a specific user context: IUSR_MachineName, or an authenticated NT domain login.

There is a known problem in Internet Explorer version 3.02. When performing uploads with NT Challenge/Response Authentication, the browser will report an error of "Could not open site. TBS".

For more information about this bug, see Microsoft Knowledge Base article Q169546.

It is the responsibility of the System Administrator to ensure that NTFS permissions are set correctly so that users performing uploads do not interfere with proper operation of the web server.

The largest source of our support questions is security. Fortunately, most problems do not occur from interference, but rather because security is too restrictive and SA-FileUp cannot function.

Here are some general guidelines:
  • Do prevent write access to critical directories such as "C:\", "C:\WINNT", and "C:\WinNT\System32".

  • Do audit scripts to ensure that ASP developers are writing to correct locations.

  • Do audit scripts to ensure that an instance of SA-FileUp is not created as an Application variable.

  • Do use the .Path property to set an appropriate file system path to contain the upload cache. SA-FileUp needs a file cache to function. If the .Path property is not set, SA-FileUp will use the default temporary directory of the system, which is typically C:\TEMP or C:\WINNT. Ideally, use the Path property in all of your web applications and allow IUSR_MachineName to write to your specific upload directory. As an alternative, ensure that the system's temporary directory can be written to by IUSR_MachineName.

  • Don't prevent the IUSR_MachineName account from reading the system registry, especially the HKEY_CLASSES_ROOT hive.

  • Don't prevent the IUSR_MachineName account from reading the SAFILEUP.DLL file.

  • Don't leave the default Everyone-Everything permission on a publicly available web server.

Since SA-FileUp is entirely controlled by server-side script, it is unlikely that a user with a browser could interfere with the operation of a web server.

The responsibility of secure and stable operation falls on the developer of the scripts and the administrator of the system.

 

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