Windows Media Player skin (*.wmz) files use gnu zip format, which triggers the true file type gz filter (GNU ZIP). The description of this file format can be found here.
To avoid blocking *.wmz files, the true file type attachment filter for gz must be deselected. Refer to the following image:
Interscan Messaging Security Virtual Appliance9.0 , Interscan Messaging Security Virtual Appliance8.5
Mails with *.wmz attachment are quarantined by the true file type attachment filter, even when there is no attachment filter defined for *.wmz files.
In the scanner log, the following trigger information show up:
log.imss.<date>.<count>
=======================
2015/07/27 17:24:39 GMT+08:00 [18192:4124452560] [NORMAL]eManagerFilter: Entity name: image003.wmz Reason: <<<FTYPE>>>GNU ZIP<<<IN SELECT>>> Index:1
2015/07/27 17:24:39 GMT+08:00 [18192:4124452560] [NORMAL]eManagerFilter: Entity name: image006.wmz Reason: <<<FTYPE>>>GNU ZIP<<<IN SELECT>>> Index:1
...
2015/07/27 17:24:39 GMT+08:00 [18192:4124452560] Final action 0: QuarantineAction
=======================
Windows Media Player skin (*.wmz) files use gnu zip format, which triggers the true file type gz filter (GNU ZIP). The description of this file format can be found here.
To avoid blocking *.wmz files, the true file type attachment filter for gz must be deselected. Refer to the following image:
