Supported File Types

The following file types and extensions are currently supported by Glasswall.  Glasswall offers two levels of CDR for our supported file types.

Comprehensive

Glasswall extrapolates the file to its granular levels, then inspects and validates every component, their relationships, and their attributes in accordance with the file vendor specification.

Learn more about content management & policy definitions. 

Standard

Glasswall extrapolates the file at a high level (e.g., container level), then validates these components against a subset of selected rules from the file vendor specification. For example, Glasswall may validate attributes of a container and ensure that the streams are of the correct size, running order, and encoding in relation to the container metadata. However, the contents of these streams are not further inspected, validated, or cleansed.

Supported File Size

Glasswall provides 64-bit version of a Dynamic-link Libraries (.DLL) for Windows and/or Shared Objects (.SO) for Linux operating systems that can analyse and protect files up to the size of 2GiB (2,147,483,648 bytes), provided that other internal limits (such as recursion depth) are satisfied.

Special Cases and Limitations

Embedded Files

The content management switch embedded_files applies to unsupported or unrecognised embedded objects or files. If an embedded object is a file type that Glasswall supports and it is permitted as an embedded object according to the containing file formats specification, the Glasswall Embedded Engine will process the embedded file with its own configuration management policies as if it were a standalone file. If the embedded file is successfully regenerated, the clean file will be re-embedded. If the embedded file can't be cleaned and regenerated, the file it is embedded into will be marked as non-conforming. If an embedded object is a file that Glasswall cannot attempt to process (unrecognised, unsupported or not permitted as an embedded object), then the embedded object is placed under the control of the containing files content management policy.

Binary Office

The content management switch macros (when set to sanitise) in Protect Mode removes the VBA script from the regenerated file but preserves the macro storage container. This can give the impression that the macros have not been deleted.

Limitations

Office 95 and earlier versions are not supported. If these file types are processed, they will cause an Issue to be reported in the XML report (in Analysis Mode) and the file will not be regenerated in Protect Mode.

Binary Office files containing Apple Mac or LibreOffice specific file features may be marked as non-conforming.

Office Open XML

Limitations

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

Encrypted Files

Limitations

Glasswall does not currently provide the ability to decrypt files, therefore encrypted files are not supported and are marked as non-conforming and blocked by default.

MathType Equation Format (MTEF)

Basic support for version 3 and 5 currently supported. Further documentation on the format is here:

https://docs.wiris.com/en/mathtype/office_tools/mathtype-sdk/mtefstorage

https://rtf2latex2e.sourceforge.net/MTEF3.html

Non-CDR Formats

Archive Support

For the Embedded Engine SDK, we recommend that integrators explode archives before presenting files for CDR processing.

Glasswall Halo provides archive support. Archive formats and file types are first identified using a structural check and then decompressed. Glasswall Halo provides REST API endpoints that that can accept both single and archive files.

This overview describes how the Glasswall Halo solution provides a configurable ruleset for how archives are processed.

Plain Text Files

Plain text files using UTF-8 or ASCII encoding are only supported by the filetype detection functionality and by Word Search when enable_text_support is specified true under sysConfig. Attempting to run analysis or protect on a plain text file will result in the file being reported as unsupported and blocked.

Binary Formats

Binary executable files should be used with caution and the use of additional security filters is highly recommended.

Binary files are inspected at the container level where headers, sections and metadata are validated against the relevant standard, however binary files may still be risky in nature given a full decompilation is not performed to reverse engineer any source code.

The table below specifies the binary formats that the Embedded Engine will inspect and validate at the container level only.

Learn more

• Glasswall CDR FAQs

• File type specifications