MSFT Updates Outlook Ban List for Downloads

Microsoft did some Outlook tweaking recently. They realized that the list of the file extensions that the program should refuse to download needed some updating.

Microsoft did some Outlook tweaking recently. They realized that the list of the file extensions that the program should refuse to download
needed some updating
.
Now, there will be consequences from this. For example, an enterprise (especially) has to make sure that the OwaMailboxPolicy objects changes are handled correctly for each user should they want enterprise-wide download exclusion.
In any case, MSFT says that the newly blocked file types are rarely used, so most organizations will not be affected by the change. However, if your users are using previously approved OMPs while sending and receiving the affected attachments, MSFT says that they will no longer will able to download them.
But, there is a way around this. If you want a particular file type to be allowed for a user, you can add that file type to the AllowedFileTypes property of your users OMP objects. A file extension will not be added to a users BlockedFileTypes list if that extension is already present in the AllowedFileTypes list.
The results of the list twiddling this time around is fairly long. From the Python scripting language, we find some obsolete file types, including .py, .pyc, .pyo, .pyw, .pyz, .pyzw. The PowerShell scripting language -- an enabler of much filleless malware coding -- also gets trimmed. The .ps1, .ps1xml, .ps2, .ps2xml, .psc1, .psc2, .psd1, .psdm1, .cdxml and .pssc extensions are on the darklist.
The .appref-ms extension used by Windows ClickOnce gets hit as does the Microsoft Data Access Components (MDAC) extension .udl. Windows sandbox gives up .wsb to the effort.
Digital certificates aren’t forgotten in the hullabaloo. The .cer, .crt and .der extensions used by some are now gone.
The .jar and .jnlp extensions to be cut are used by the Java programming language quite extensively. Java is so powerful that allowing it unrestrained program access could prove seriously problematical from a security standpoint. Yet, there may be libraries in use by production code which assume they will be able to get to files containing that extension. Thats a potential quagmire for an enterprise, especially if it relies on open sourced software.
From the Department of Youre Too Lame to Patch, So We Did It for You came some extensions that MSFT explained this way. While the associated vulnerabilities have been patched (for years, in most cases), they said in the advisory, they are being blocked for the benefit of organizations that might still have older versions of the application software in use. Lame-o.
The list of the miscellaneous ones is :.appcontent-ms, .settingcontent-ms, .cnt, .hpj, .website, .webpnp, .mcf, .printerexport, .pl, .theme, .vbp, .xbap, .xll, .xnk, .msu, .diagcab and .grp.
— Larry Loeb has written for many of the last centurys major dead tree computer magazines, having been, among other things, a consulting editor for BYTE magazine and senior editor for the launch of WebWeek.

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MSFT Updates Outlook Ban List for Downloads