From Microsoft they want to extend the number of prohibited extensions in Outlook. This is due to the danger it can pose to users. Of course, this would only affect users of Outlook on the web, or Outlook Web Access (OWA).
Outlook shields itself against certain extensions
The extensions to date were 104 and now 38 more file extensions are included. These extensions are often used to perform malware attacks.
Once they are added to the list of blocked file extensions, users will not be able to download these files from our mail. This can only be activated by an Exchange administrator and individually for each extension and through a special configuration.
“The new blocked extensions are used very little, most organizations will not notice the change,” says the Microsoft Exchange team.
These are the 38 types of extensions that will soon be banned in Outlook for the web.
- Java files: “.jar”, “.jnlp”
- Python files: “.py”, “.pyc”, “.pyo”, “.pyw”, “.pyz”, “.pyzw”
- PowerShell: “.ps1”, “.ps1xml”, “.ps2”, “.ps2xml”, “.psc1”, “.psc2”, “.psd1”, “.psdm1”, “.psd1”, “.psdm1 “
- Digital Certificates: “.cer”, “.crt”, “.der”
- Files to exploit third-party vulnerabilities: “.appcontent-ms”, “.settingcontent-ms”, “.cnt”, “.hpj”, “.website”, “.webpnp”, “.mcf”, “.printerexport” , “.Pl”, “.theme”, “.vbp”, “.xbap”, “.xll”, “.xnk”, “.msu”, “.diagcab”, “.grp”
If you do not know the 104 extensions currently blocked you can see them here. From Microsoft it has not been indicated when these extensions will be added but it will be soon. You know, mail files become more controlled to avoid unpleasant surprises.