Sending Prohibited Attachments

Many mail servers, including SEAS and Gmail, block dangerous attachments. New viruses will slip past anti-virus software, and some mail readers are at risk even if the user does not choose to open the attachment, so these attachments are very dangerous.

Which extensions are prohibited?

The following file types are automatically blocked by our spam filter:

386, 3gr, add, ade, adp, ani, apk, app, appcontent-ms, application, appref-ms, appx, appxbundle, asp, aspx, asx, bas, bat, bgi, cab, cer, chm, class, cmd, cnt, com, cpl, crt, csh, cur, dbx, der, diagcab, diagcfg, diagpack, dll, dmg, ex, ex_, exe, fon, fxp, gadget, grp, hlp, hpj, hta, htc, ico, img, inf, ins, iso, isp, its, jar, jnlp, js, jse, ksh, lib, lnk, mad, maf, mag, mam, maq, mar, mas, mat, mau, mav, maw, mcf, mda, mdb, mde, mdt, mdw, mdz, msc, msh, msh1, msh1xml, msh2, msh2xml, mshxml, msi, msix, msixbundle, msp, mst, msu, nsh, ocx, ops, osd, pcd, pif, pl, plg, prf, prg, printerexport, ps1, ps1xml, ps2, ps2xml, psc1, psc2, psd1, psdm1, pst, py, pyc, pyo, pyw, pyz, pyzw, rar, reg, scf, scr, sct, settingcontent-ms, sh, shb, shs, sys, theme, tmp, url, vb, vbe, vbp, vbs, vhd, vhdx, vsmacros, vsw, vxd, webpnp, website, wmf, wmz, ws, wsc, wsf, wsh, xbap, xll, xnk

If someone sends you an email with a prohibited attachment, it will be rejected with an error message to the sender.

The system will also examine attachments to determine their type, so changing the extension won't necessarily get a file through the filter. Some operating systems don't use filename extensions, but their executables will still be blocked. Attached archives (such as ZIP) will also be inspected and blocked if they contain the prohibited file types.

Please see these pages for more information about Penn email routing and spam filtering:

Penn Email Routing (Penn Information Systems & Computing)

ProofPoint Hygiene Rules (Penn+Box, PennKey authentication required)

How can someone send a prohibited attachment so that it gets through?

If someone needs to send you a file with one of the prohibited extensions, please consider other options to share documents securely.