Full Report
Security researchers have disclosed a new Secure Boot bypass tracked as CVE-2025-3052 that can be used to turn off security on PCs and servers and install bootkit malware. [...]
Analysis Summary
# Vulnerability: Secure Boot Bypass Enabling Bootkit Installation
## CVE Details
- CVE ID: CVE-2025-3052
- CVSS Score: Not explicitly provided, but implied High due to ability to install malware before OS loading.
- CWE: Not explicitly detailed (likely related to Improper Access Control or Improper Validation within firmware execution).
## Affected Systems
- Products: Systems utilizing Microsoft's Secure Boot implementation (specifically the module enforcing Secure Boot integrity).
- Versions: Affected systems are those running vulnerable firmware prior to the application of the dbx revocation list update.
- Configurations: Systems where Secure Boot is expected to be active during the boot process.
(Note: The article also references a second flaw, CVE-2025-4275, affecting Insyde H2O firmware, but this summary focuses on CVE-2025-3052 as the primary subject of the article's initial focus.)
## Vulnerability Description
This vulnerability targets the Microsoft Windows boot environment and specifically affects the mechanisms responsible for enforcing Secure Boot integrity early in the boot process. An attacker can exploit this flaw to overwrite the `gSecurity2` global variable, which holds a pointer to the Security2 Architectural Protocol. By setting this pointer to zero, the attacker effectively disables Secure Boot checks within the `LoadImage` function, allowing any unsigned UEFI modules to be executed before the operating system loads. This allows for the installation of persistent bootkit malware.
## Exploitation
- Status: PoC available (Created by Binarly)
- Complexity: Implied Medium/High, requires pre-OS access or privilege to modify the relevant memory structure during boot.
- Attack Vector: Typically requires local access or potential pre-OS execution capability, though the mechanism bypasses OS security layers.
## Impact
- Confidentiality: High (Bootkit can persist, steal credentials, or monitor pre-OS activity)
- Integrity: High (Full control over the early boot environment allows for permanent compromise of the system integrity)
- Availability: Medium/High (A persistent bootkit can reduce system stability or lead to denial of service)
## Remediation
### Patches
- **Microsoft has issued updates** to address this issue by adding the affected module hashes to the **Secure Boot dbx revocation list**.
- Users must install **today's security updates** from Microsoft which contain the updated dbx file. (Specific KB numbers are not provided for CVE-2025-3052 in this excerpt).
### Workarounds
- Install the updated dbx file immediately via Microsoft's security updates.
- Ensure UEFI firmware settings enforce Secure Boot policies if possible, though the vulnerability aims to bypass these enforcement checks.
## Detection
- **Indicators of Compromise:** Post-exploitation indicators would relate to the presence of rootkits/bootkits capable of residing outside the OS partition.
- **Detection methods and tools:** Detection relies heavily on updating the dbx revocation list. Monitoring BIOS/UEFI logs for unexpected loading events before the OS handoff might reveal anomalies, although this is difficult if the bootkit successfully defeats standard checks.
## References
- Vendor Advisory: Binarly report: defanged.binarly.io/blog/another-crack-in-the-chain-of-trust
- Additional Reference (CVE-2025-4275, Insyde H2O Flaw): defanged.coderush.me/hydroph0bia-part1/