2.8 Evaluate Firmware Update Security
Here is the completed documentation template for Section 2.8 – Evaluate Firmware Update Security:
2.8 Evaluate Firmware Update Security
Requirement Description:
Verify that the firmware update process is not vulnerable to time-of-check vs. time-of-use (TOCTOU) attacks.
DUT Software Details:
(To be filled by OEM/vendor – e.g., Linux Kernel 5.x, Custom Firmware v1.2.3, Update Module v2.0, etc.)
Hash Checksum Verification for DUT’s Software Image:
(e.g., SHA-256: af84a9...
) — to validate firmware integrity prior to testing.
DUT Configuration:
(Document any settings enabled for update verification, secure boot, signed packages, etc.)
Pre-Conditions:
The vendor shall provide the following:
Documentation on TOCTOU protections implemented during the firmware update process.
Description of how the integrity check is bound to the execution/installation of the update file (i.e., atomic validation and use).
Test Plan
Total Number of Test Cases: 1
Test-bed Diagram with Interfaces and IPs:
(Include layout of update server, test system, DUT IP, etc. For example: DUT @ 192.168.1.10, Update Server @ 192.168.1.100)
✅ TEST CASE DETAILS
Test Case: BIS-2.8.1
Test Name: TC_EVALUATE_FIRMWARE_UPDATE_SECURITY_TOCTOU
Objective:
To verify, in the presence of the OEM team, that the firmware update process is protected against Time-of-Check to Time-of-Use (TOCTOU) vulnerabilities.
Tools Used:
Custom firmware patching tools or update file swapper script
Wireshark (for traffic observation, optional)
File system access tools (e.g., SSH/SCP to monitor
/tmp
or/var
dirs)Logging/monitoring scripts
Test Execution Steps:
Initiate a legitimate firmware update procedure on the DUT.
Before the actual installation/execution of the firmware, attempt to replace the verified firmware image with a tampered version after validation but before use.
Observe if:
The device re-validates the image immediately before use.
The tampered image gets blocked or gets installed.
Monitor logs, behaviors, and cryptographic validations, if applicable.
Cross-check with OEM documentation on atomicity and protection of the update process.
Expected Results for Pass:
The DUT detects any tampering attempt between the check and use phase.
Firmware image is re-validated immediately prior to execution.
The update is aborted or rolled back if the image fails re-validation.
Logs or alerts are generated to indicate the detection of tampering.
Test Observations:
(To be documented during test — e.g., “Tampered image was successfully blocked; checksum mismatch detected during re-validation.”)
Evidence Provided:
Screenshots of logs
Output of hash mismatch detection
Tool-generated activity timeline
OEM confirmation of re-validation mechanism
Test Case Result:
(Pass/Fail based on behavior)
Overall Test Result:
(Pass/Fail for Section 2.8)
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