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File Type Specifications
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    File Type Specifications

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      Article Summary

      File Type Specifications

      PDF

      Specification Validated Against:

      • PDF Reference (third edition) Adobe Portable Document Format Version 1.7.

        Note: Glasswall supports PDF Reference (third edition) Adobe Portable Document Format from Version 1.3.

      Images

      There are no content management switches for any of the image file formats. Images embedded in a document which do not conform to the specification would result in the original document being quarantined.

      JPG

      Specification Validated Against:

      • JPEG File Interchange Format, Version 1.02 September 1, 1992
      • JP2 for ISO/IEC 15444-1 (JPEG 2000)
      • JPX for ISO/IEC 15444-2 (JPEG 2000)

      GIF

      Specification Validated Against:

      • Graphics Interchange Format, Version GIF 87
      • Graphics Interchange Format, Version GIF 89a

      PNG

      Specification Validated Against:

      • Portable Network Graphics (PNG): Functional specification. ISO/IEC 15948:2003 (E)

      EMF

      Specification Validated Against:

      • [MS-EMF]: Enhanced Metafile Format: Open Specifications Documentation. v20151016
      • [MS-EMFPLUS]: Enhanced Metafile Format Plus Extensions: : Open Specifications Documentation. V20121017

      WMF

      Specification Validated Against:

      • [MS-WMF]: Windows Metafile Format: Open Specifications Documentation. v20121017

      TIFF and GeoTIFF

      Specification Validated Against:

      • TIFF 6.0 Specification: Final – June 3, 1992
      • GeoTIFF Format Specification - Specification Version: 1.8.1

      BMP

      Specification Validated Against:

      • BMP is covered by the WMF file specification.

      Binary Office

      Processing Specific to Binary Office in Protect Mode

      The content management switch GWFILE_MANAGE_REMOVE_MACROS when set to sanitise in Protect mode removes the VBA script from the regenerated file but copies over the macro container. This can give the impression that the macros have not been deleted.

      The content management switch GWFILE_MANAGE_REMOVE_EMBEDDED_FILES when set to sanitise in Protect mode do one of two options.

      • If the embedded file is one that Glasswall supports it will process that file as if it were a standalone file, including its own configuration management polices if appropriate. If the file can be regenerated the regenerated file will be re-embedded, if it cannot the file it is part of will be marked as non-conforming.
      • If the embedded file is one that Glasswall cannot process like a .mdb or .dat file then the embedded file is removed.

      Embedded files are validated to five levels deep.

      DOC

      Specifications Validated Against:

      The following specifications are used to validate a doc file type:

      • From [MS-DOC]: Word (.doc) Binary File Format - Microsoft Corporation, 2011, v20121003 to [MS-DOC]: Word (.doc) Binary File Format - Corporation, 2017, v20170112
      • Office Common Data Types and Objects Structure Specification- Microsoft Corporation, 2011, v20110608
      • Office Document Cryptography Structure Specification- Microsoft Corporation, 2011, v20110608
      • Office VBA File Format Structure Specification- Microsoft Corporation, 2011, v20110608

      Non Supported Specifications:

      Word 95 and earlier versions (Word 1 to Word 6) are not supported and if these file types are processed they will cause an Issue to be reported in the XML report  in Analysis mode and the file not to be regenerated in Protect mode.

      Word files containing Apple Mac or LibreOffice specific file features will be marked as non conformant.

      XLS

      Specifications Validated Against:

      The following specifications are used to validate an xls file type:

      • From [MS-XLS]: Excel Binary File Format (.xls) Structure Specification - Microsoft Corporation, v20141018 to [MS-XLS]: Excel Binary File Format (.xls) Structure Specification - Microsoft Corporation, v20161017.
      • Spreadsheet Data Model File Format
      • Office Graph Binary File Format v20141019

      Non Supported Specifications:

      Excel 95 and earlier versions are not supported and these file types are processed cause an Issue to be reported in the XML report  in Analysis mode and the file not to be regenerated in Protect mode.

      Excel files containing Apple Mac or LibreOffice specific file features will be marked as non conformant.

      PPT

      Specifications Validated Against:

      The following specifications are used to validate a PowerPoint file type against:

      • From [MS-PPT]: PowerPoint (.ppt) Binary File Format - Microsoft Corporation, v20121003 to [MS-PPT]: PowerPoint (.ppt) Binary File Format - Microsoft Corporation, v20160922.

      Non Supported Specifications:

      PowerPoint 95 and earlier versions are not supported and if these file types are processed it will cause an Issue to be reported in the XML report  in Analysis mode and the file not to be regenerated in Protect mode.

      PowerPoint files containing Apple Mac or LibreOffice specific file features will be marked as non conformant.

      XML Office

      Processing Specific to XML Office in Protect Mode

      If a XML Office file has another XML Office file embedded inside it and the GWFILE_MANAGE_REMOVE_EMBEDDED_FILES is set to sanitise, the embedded file will be removed when a new file is regenerated.

      Office XML files are stored as zipped archive files and although the zipped file may be less than 10Mb when the streams are extracted and uncompressed an individual stream may be greater than 10MB. When using the 32-bit DLL, streams that are larger than that 10 MB cause the file to be marked as non–conforming and are not processed any further. When using the 64-bit DLL, streams of up to 50MB are processed.

      Office 2010

      The following specifications are used to validate docx/xlsx/pptx file types:

      Office 2013

      The following specifications are used to validate docx/xlsx/pptx file types:

      • Word (.docx) Extensions to the Office Open XML SpreadsheetML File Format
      • Excel (.xlsx) Extensions to the Office Open XML SpreadsheetML File Format
      • PowerPoint  (.pptx) Extensions to the Office Open XML SpreadsheetML File Format
      • Office Drawing Extensions to the Office Open XML Structure

      Non Supported Specifications:

      Office 2010 or Office 2013 files containing Apple Mac or LibreOffice specific file features may be marked as non conformant or the components may be removed from the file.

      Other

      WAV

      Specifications Validated Against:

      • Multimedia Programming Interface and Data Specifications 1.0 August 1991.

      MPG

      Specifications Validated Against:

      • ISO/IEC 13818-1:2000(E). Second edition 2000-12-01

      MP3

      Specifications Validated Against:

      MPEG Layer III audio encoding is defined in two ISO/IEC specification families:

      • MPEG-1: ISO/IEC 11172-3. Information technology -- Coding of moving pictures and associated audio for digital storage media at up to about 1,5 Mbit/s -- Part 3: Audio.
      • MPEG-2: ISO/IEC 13818-3. Information technology -- Generic coding of moving pictures and associated audio information -- Part 3: Audio.

      MP4

      Specification Validated Against:

      • ISO/IEC 14496-12:2005(E). Part 12: Corrected version 2005-10-01.

      PE and COFF

      Specifications Validated Against:

      • Microsoft Portabole Executable and Common Object File Format Spcecification Revision 6.0 – February 1999.

      ELF

      Specifications Validated Against:

      • Tool Interface Standard (TIS) Executable and Linking Format (ELF) Specifiaction Version 1.2. May 1995
      • ELF-64 Object File Format Version 1.2 Draft 2. May 27, 1998.

      Mach-O

      Specifications Validated Against:

      • OS X ABI Mach-O File Format Reference. 2009-02-04.
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