# Firmware verifier accepts unauthenticated protected bytes

The relevant update acceptance path fails to authenticate executable payload or security-relevant metadata correctly.

**Candidate CWE:** [CWE-347](https://cwe.mitre.org/data/definitions/347.html)

## Test hypothesis

Compare an authentic image with a format-valid disposable copy containing one harmless changed protected field or missing signature. Use the real verifier in a local validation path and record the acceptance stage.

## Evidence required

Original/modified hashes, byte location, covered ranges, trust key source and parser-versus-signature decisions.

## Rule out false positives

Accepting an image for inspection or staging does not prove installation or execution; unprotected padding may be intentional.

## Playbook and command references

- [Firmware update and boot trust: signed bytes, product binding and rollback](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/modules/firmware-update.html) — Separate download trust, update authorization, image verification, rollback policy and boot enforcement using local artifacts.

[Find the associated command snippets](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/commands.html?q=Firmware%20update%20and%20boot%20trust%3A%20signed%20bytes%2C%20product%20binding%20and%20rollback)

## Referenced by these target playbooks

[Hardware & firmware](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/hardware.html) · [OSS & self-hosted](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/oss.html)

## Report checklist

- [ ] Capture the affected version, configuration, identities, and object ownership.
- [ ] Preserve a valid baseline and a negative control.
- [ ] Reproduce the forbidden data access, action, or state change on controlled fixtures.
- [ ] Explain the intended security rule and why the observed behavior violates it.
- [ ] State prerequisites, uncertainty, cleanup, and the smallest demonstrated impact.

## Conditional ATT&CK mapping

- [T1542.001 · Pre-OS Boot: System Firmware](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/attack.html#T1542-001) — **Only if:** A lab demonstration modifies system firmware, such as BIOS/UEFI, to maintain execution/access across boot; record the firmware component, persistence behavior, and recovery procedure. **Not established by:** Downloading firmware, finding an embedded password, or detecting missing signature checks alone is not firmware persistence. Ordinary application firmware packaging needs component-level analysis.
- [T1542.002 · Pre-OS Boot: Component Firmware](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/attack.html#T1542-002) — **Only if:** A controlled reproduction modifies peripheral/component firmware to preserve execution or access outside the main OS/system firmware, with evidence of that persistence. **Not established by:** A firmware binary containing a vulnerable library is insufficient. Do not treat every IoT firmware issue as either system firmware or component firmware persistence.

## Primary references

- [OWASP firmware update tests](https://github.com/OWASP/owasp-istg/blob/main/src/03_test_cases/firmware/firmware_update_mechanism.md)

[Back to the complete vulnerability catalog](https://bug-bounty-field-manual.kmahshooq.chatgpt.site/vulnerabilities.html)