Cracking Firmware with Claude Senior-Level Skill, Junior-Lev...

[carlospolop]

🤖 Automated Content Update

This PR was automatically generated by the HackTricks News Bot based on a technical blog post.

📝 Source Information

• Blog URL: https://bishopfox.com/blog/cracking-firmware-with-claude-senior-level-skill-junior-level-autonomy
• Blog Title: Cracking Firmware with Claude: Senior-Level Skill, Junior-Level Autonomy
• Suggested Section: Hardware/Physical Access > Firmware Analysis, with cross-references from Reversing and Crypto

🎯 Content Summary

Overview: The post describes a hands-on firmware-reversing and key-extraction experiment in which Bishop Fox used Claude Code running Sonnet 4.5 to decrypt a proprietary SonicWall SWI firmware image. This is not presented as a CVE and no CVE number is assigned; the value is in the detailed methodology for defeating firmware confidentiality by recovering operational decryption keys from a decrypted appliance filesystem.

Target artifacts and goal: The researcher provi...

🔧 Technical Details

Firmware container triage using magic bytes and length-based crypto inference: When analyzing an encrypted firmware format, first map the file structure: readable headers, signatures, base64 lines, magic bytes, offsets, and ciphertext boundaries. In this case, Salted__ at offset 0x366 identified OpenSSL enc formatting, where the following 8 bytes are the salt and the rest is encrypted payload. A base64 blob decoding to exactly 256 bytes strongly indicated an RSA-2048 ciphertext, suggesting a hybrid encryption design: RSA wraps a firmware password/session key, and AES-256-CBC encrypts the bulk payload.

Reverse the operational decrypt path instead of only searching for private keys: If grep and strings do not reveal a private key, inspect the binary that normally processes updates. Decompiled updater logic can expose the exact decrypt function, backend KMS, key name, and data flow. Here, ...

🤖 Agent Actions

Updated src/hardware-physical-access/firmware-analysis/README.md.

Added a concise new section covering:

• encrypted firmware container triage (Salted__, 256-byte RSA blob, mixed plaintext/ciphertext)
• reversing the appliance-side decrypt path instead of only hunting PEM keys
• abusing embedded Vault/KMS unseal automation in extracted filesystems
• replaying the vendor Vault binary + storage instead of reimplementing nested Vault crypto
• exporting transit keys and testing RSA OAEP/hash parameters
• reproducing OpenSSL EVP_BytesToKey + AES-CBC decryption offline

Also added the Bishop Fox blog URL under the existing ## References section.

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[carlospolop]

🔗 Additional Context

Original Blog Post: https://bishopfox.com/blog/cracking-firmware-with-claude-senior-level-skill-junior-level-autonomy

Content Categories: Based on the analysis, this content was categorized under "Hardware/Physical Access > Firmware Analysis, with cross-references from Reversing and Crypto".

Repository Maintenance:

• MD Files Formatting: 981 files processed

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Bot Version: HackTricks News Bot v1.0