CS35L27-Covert-Channel-Analysis/docs/analysis-methods.md

Analysis Methods

This document details only the objective methods and data sources used in the analysis of CS35L27 firmware. All narrative, interpretative, or speculative commentary has been excluded.

Primary Data Sources

• Official CS35L27 firmware binary images.
• Publicly available datasheets and documentation from Cirrus Logic.
• Vendor-provided utilities for extracting firmware contents, where publicly redistributable.
• Open-source reverse engineering tools (e.g., Ghidra, Binwalk).

Objective Methods

1. Firmware Extraction

• Direct extraction of binary images from hardware or distribution files.
• Verification of image integrity through checksums or hashes.

2. Binary Analysis

• Use of Ghidra and Binwalk for static analysis of binary structure.
• Identification and separation of code, data, and metadata sections.

3. Strings and Pattern Search

• Systematic use of strings and regular expressions to locate text and code patterns in binaries.

4. Function Identification

• Automated function boundary detection via Ghidra.
• Cross-referencing documented routines with observed binary segments.

5. Data Extraction

• Extraction of configuration tables and constant data from designated binary offsets using custom scripts.

6. Comparative Analysis

• Byte-wise and structural comparisons between multiple firmware images using cmp, diff, and custom tooling.

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All steps above use only publicly available tools and verifiable methods. No conclusions, narrative interpretations, or speculative extrapolations are included in this document.