Full Report
Talos reported 5 vulnerabilities to Broadcom and Dell affecting both the ControlVault3 Firmware and its associated Windows APIs that we are calling “ReVault”.
Analysis Summary
As a vulnerability research specialist, here is the summary of the disclosed security research regarding Dell ControlVault:
# Vulnerability: Compromise of Dell ControlVault Firmware via Local Attack
## CVE Details
- CVE ID: **Not explicitly provided in the text.** (The article discusses pre-patch research findings; CVE assignment is not detailed.)
- CVSS Score: **Not provided in the text.**
- CWE: (Not explicitly provided)
## Affected Systems
- Products: Dell laptops utilizing **Dell ControlVault3** or **ControlVault3+** hardware security solution, which incorporates a **Unified Security Hub (USH)** board leveraging Broadcom BCM5820X series chips.
- Versions: Affects implementations using ControlVault3/3+. Specific software/firmware version ranges are **not provided**.
- Configurations: Systems where ControlVault services run with SYSTEM privileges and lack modern protections like ASLR, enabling local privilege escalation pathways.
## Vulnerability Description
The research targets Dell ControlVault, a hardware-based security solution storing credentials and biometrics within firmware on a dedicated daughterboard (USH). The investigation revealed several critical weaknesses:
1. **Firmware Interrogation:** Difficulty in decrypting/unpacking proprietary firmware components (specifically files named `bcmCitadelXXX`).
2. **Service Exploitation:** Associated Windows services run without **Address Space Layout Randomization (ASLR)** and hold **SYSTEM privileges**, presenting targets for Local Privilege Escalation (EoP).
3. **Exploitation Path:** The core issue stems from the ability for a local attacker to **modify the firmware running on the USH board.**
## Exploitation
- Status: **Research findings documented; exploitation confirmed (local attacker scenario).** The research demonstrates potential for modification that can lead to compromise, even surviving OS reinstalls.
- Complexity: **Medium** (Requires local access and technical knowledge to decrypt firmware/interact with specific drivers).
- Attack Vector: **Local** (Requires an already compromised workstation or local user privileges).
## Impact
- Confidentiality: **High** (Potential compromise of stored passwords, biometric templates, and security codes).
- Integrity: **High** (Ability to tamper with firmware security mechanisms and operate with SYSTEM privileges).
- Availability: **Medium** (Potential for service instability or custom firmware implants).
## Remediation
### Patches
- **Patches are referenced via documentation links mentioning ControlVault drivers, but specific patch versions addressing the identified weaknesses are not listed in this summary.** Users should check Dell support for the latest ControlVault/USH firmware and driver updates associated with their specific laptop model.
### Workarounds
1. **Firmware Verification:** Run processes (as detailed in the original research) to verify that legitimate firmware updates can be successfully installed and return the expected version string.
2. **Service Monitoring:** Monitor for unexpected process activity attempting to load `bcmbipdll.dll` or opening unauthorized handles to the ControlVault device interface (GUID: `{79D2E5E9-8883-4E9D-91CBA14D2B145A41}`).
3. **Crash Monitoring:** Watch for unexpected crashes in related services: `WinBioSvc`, `bcmHostStorageService`, `bcmHostControlService`, or `bcmUshUpgradeService`.
4. **Device Manager Status Check:** Inspect the "Versioning" panel for the ControlVault device in Device Manager to confirm expected firmware version reporting.
## Detection
- **Indicator of Compromise (IoC):** Unexpected processes loading `bcmbipdll.dll`. Attempts to open unexpected handles to the ControlVault device interface.
- **Detection Methods and Tools:** Utilize system monitoring tools to track process injection/handle access related to the ControlVault device interface GUID or monitor unexpected crashes in ControlVault services. Verifying successful, expected firmware version reporting post-update.
## References
- Vulnerability Spotlight: hXXps://blog.talosintelligence.com/revault-when-your-soc-turns-against-you/
- Dell Driver Link (Example): hXXps://www.dell.com/support/home/en-vc/drivers/driversdetails?driverid=twf65
- NIST Certification (Broadcom Chip): hXXps://csrc.nist.gov/CSRC/media/projects/cryptographic-module-validation-program/documents/security-policies/140sp3920.pdf
- Linux Support Repo (Source Intel): hXXps://git.launchpad.net/~oem-solutions-engineers/libfprint-2-tod1-broadcom/+git/libfprint-2-tod1-broadcom/