In order to protect our users against unknown viruses, we block attachments that have any of the filename extensions listed below. Emails that contain any such attachments will be rejected, and an error message will be returned to the sender.
This list is based on the "dangerous attachment types" blocked by Microsoft Outlook.
More details about our email scanner.
In this table, [] means any of the enclosed letters, ()? indicates an optional suffix, and []? means an optional letter.
| .ad[ep] | Microsoft Access file |
| .app | executable application |
| .appcontent-ms | Application content |
| .asp | Microsoft Active Server Page |
| .appref-ms | Microsoft Windows ClickOnce |
| .bas | BASIC source code |
| .bat | Microsoft command script |
| .cdxml | Windows PowerShell |
| .cer | security certificate |
| .chm | compiled HTML help |
| .cmd | executable command |
| .cnt | Microsoft Help Workshop Application |
| .com | executable command |
| .cpl | Microsoft Windows control panel |
| .crt | security certificate |
| .der | DER-encoded X.509 certificate |
| .diagcab | Microsoft Support Diagnostic Tool |
| .dot | Microsoft Word template |
| .exe | executable program |
| .fxp | FoxPro code |
| .gadget | Microsoft Windows Vista gadget |
| .grp | Microsoft program group |
| .hlp | Microsoft Windows help file |
| .hta | hypertext application |
| .hpj | AppWizard Help project |
| .inf | information / setup file |
| .ins | Internet communications settings |
| .isp | Internet service provider settings |
| .its | Internet document set |
| .jar | Java archive |
| .jnlp | Java Network Launch Protocol file |
| .jse? | JavaScript code |
| .lnk | Microsoft Windows shortcut |
| .ma[dfgmqrstvw] | Microsoft Access |
| .mau | Media Attachment Unit |
| .mcf | Media Container Format |
| .md[abetwz] | Microsoft Access |
| .msc | Microsoft management console snap-in |
| .msh[12]?(xml)? | Microsoft Shell file |
| .ms[ip] | Microsoft Windows installer file |
| .mst | Microsoft Windows SDK setup script |
| .msu | Microsoft Windows update package |
| .ops | Microsoft Office profile settings |
| .osd | Open Software Description |
| .pcd | Microsoft Visual Test script |
| .pif | Microsoft Windows program information file |
| .pl | Perl |
| .plg | Developer Studio Build Log |
| .prf | Microsoft Windows system file |
| .prg | executable program |
| .printerexport | Windows Printer Migration wizard file |
| .ps[12](xml) | Windows PowerShell |
| .psc[12] | Windows PowerShell |
| .psd1 | Windows PowerShell |
| .psdm1 | Windows PowerShell |
| .pssc | Windows PowerShell |
| .pst | Exchange/Outlook store |
| .py[c, o, z and zw) | Python |
| .reg | registry data |
| .settingcontent-ms | Microsoft Windows setting content |
| .scf | Microsoft Windows Explorer command |
| .scr | Microsoft Windows screen saver |
| .sct | Microsoft Windows script component |
| .shb | Microsoft Windows shortcut into a document |
| .shs | Microsoft Windows scrap object |
| .theme | Microsoft Windows theme |
| .tmp | Temporary file |
| .udl | Microsoft Data Access Components |
| .url | Internet location |
| .vb[eps]? | Microsoft Visual Basic code |
| .vsmacros | Microsoft Visual Studio macro |
| .vs[stw] | Microsoft Visio file |
| .webpnp | Support for Internet Printing |
| .website | Pinned site shortcut |
| .ws[cfh]? | Microsoft Windows Script |
| .wsb | Microsoft Windows sandbox |
| .xbap | Browser Applications |
| .xll | Excel add-in |
| .xnk | Microsoft Exchange folder shortcut |
| .ani | Microsoft Windows mouse cursor |
| .cab | Microsoft installation archive |
| .cnf | Microsoft SpeedDial configuration |
| .cur | Microsoft Windows mouse cursor |
| .job | Microsoft Windows scheduled task |
| .xnk | Microsoft Exchange shortcut |
| .{long-encoded-string} | Microsoft Windows CLSID hidden file type |