Structural Repair

Structural Repair in Glasswall CDR Technology

Structural Repair is a core component of Glasswall's Content Disarm and Reconstruction (CDR) technology. It focuses on the safe reconstruction of digital files by validating and repairing their internal structures against manufacturer specifications and international standards.

The Structural Repair process is composed of two key phases: Inspect and Rebuild.

Structural Analysis

During the analysis phase, the Glasswall Embedded Engine analyzes the file’s internal composition, identifying and mapping all structural components.

• The file is parsed into a tree-like structure, similar to the Document Object Model (DOM) used in HTML.
• Any compressed elements are automatically decompressed to enable full inspection.
• If the file contains embedded objects (e.g., a JPEG image within a Word document), each embedded item is treated as a distinct file. Separate tree structures are generated for each.
• The output of this stage is a detailed structural analysis report, outlining the format, size, hierarchy, and compliance of the file’s components.

Structural Repair

In the repair phase, the Glasswall engine processes the structural tree created during inspection to validate and reconstruct the file.

• An iterator traverses the tree, validating each node against a "known good" specification, such as ISO 32000 for PDFs.

• If a structure fails validation:

  • The engine attempts to repair the structure to match the required specification.
  • If repair is not possible, the issue is logged, and the system may choose not to regenerate that part of the file.

This phase ensures that only safe, standards-compliant data is retained in the reconstructed version of the file.

Outcome

By performing Structural Repair, Glasswall ensures that all output files are fully standards-compliant, free from hidden or malformed content, and safe for use in secure environments.