CVE-2023-25756: Intel Atom X6200fe Privilege Escalation

CVE-2023-25756 Overview

CVE-2023-25756 is an out-of-bounds read vulnerability [CWE-125] in the BIOS firmware of certain Intel Processors. An authenticated user with adjacent network access can exploit this flaw to escalate privileges. The issue affects a broad range of Intel CPU families, including Atom, Celeron, Pentium Gold, and multiple generations of Core i3, i5, i7, and i9 processors. Intel published mitigation guidance in Intel Security Advisory SA-00924, and NetApp confirmed downstream platform impact in NetApp Security Advisory NTAP-20231221-0008.

Critical Impact
An authenticated attacker on an adjacent network can trigger an out-of-bounds memory read in BIOS firmware to gain elevated privileges, compromising confidentiality, integrity, and availability at the firmware layer.

Affected Products

Intel Atom x6000E series processors (x6200FE, x6211E, x6212RE, x6413E, x6414RE, x6425E, x6425RE, x6427FE)
Intel Core processors spanning 8th through 13th generation (i3, i5, i7, i9, including H, K, T, U, P, and embedded variants)
Intel Celeron, Pentium Gold, and Pentium J/N series processors with affected BIOS firmware

Discovery Timeline

2023-11-14 - CVE-2023-25756 published to NVD
2023-12-21 - NetApp publishes security advisory NTAP-20231221-0008
2024-11-21 - Last updated in NVD database

Technical Details for CVE-2023-25756

Vulnerability Analysis

The vulnerability is an out-of-bounds read condition residing inside the BIOS firmware that ships with the affected Intel processors. When the firmware processes a specific input from an authenticated source, it reads memory beyond the bounds of an intended buffer. This behavior exposes adjacent memory that may contain sensitive runtime state, control structures, or pointers used by the firmware itself.

Because the flaw resides in BIOS firmware, exploitation operates below the operating system kernel. Successful exploitation enables an authenticated attacker to escalate privileges to a level higher than what is typically reachable from a user-mode account. The attack requires adjacent network access, meaning the attacker must reside on the same physical or logical network segment as the target.

Root Cause

The defect originates from missing or insufficient boundary validation within BIOS firmware routines that handle attacker-influenced input. Classified under CWE-125: Out-of-bounds Read, the firmware reads past the end of a buffer, returning data from neighboring memory regions to a caller that can observe it.

Attack Vector

Exploitation requires three preconditions: low-level authenticated access to a host containing an affected processor, network adjacency to that host, and the ability to interact with the BIOS firmware interface that triggers the vulnerable code path. The attacker leverages the out-of-bounds read to disclose firmware memory or to manipulate firmware decision logic, ultimately enabling escalation of privilege.

No public proof-of-concept exploit code is available. The vulnerability mechanism is described in the Intel Security Advisory SA-00924.

Detection Methods for CVE-2023-25756

Indicators of Compromise

Unexpected BIOS configuration changes, firmware variable modifications, or unauthorized SMBIOS table edits on systems with affected Intel processors.
Authenticated user sessions originating from adjacent network segments that target firmware management interfaces or low-level platform services.
Anomalous privilege escalation events on hosts where the local account did not previously hold administrative rights.

Detection Strategies

Inventory all endpoints and servers to identify systems running affected Intel processor models and verify their current BIOS version against the vendor-supplied fixed versions in Intel SA-00924.
Monitor firmware integrity using platform attestation, TPM event logs, and tools that validate UEFI/BIOS measurements against a known-good baseline.
Correlate authentication telemetry with network adjacency data to identify suspicious sessions that touch firmware-related endpoints.

Monitoring Recommendations

Enable Windows Event Log auditing for privilege use, security policy changes, and driver/firmware load events; forward these logs to a centralized analytics platform.
Track BIOS version inventory drift across the fleet and alert when a system reverts to or remains on a pre-patch firmware level.
Monitor network segments for lateral movement from authenticated low-privilege users toward hosts that expose platform management protocols.

How to Mitigate CVE-2023-25756

Immediate Actions Required

Identify affected Intel processor models in your environment and prioritize them for BIOS firmware updates published by the OEM (Dell, HP, Lenovo, Supermicro, etc.) based on Intel's reference fix.
Restrict adjacent network access to platform management interfaces using network segmentation, VLAN isolation, and host-based firewalls.
Enforce least-privilege account policies so that adjacent authenticated users cannot reach firmware-interactive functionality.

Patch Information

Intel released firmware updates addressing CVE-2023-25756 and instructs system manufacturers to deliver fixed BIOS releases. Refer to Intel Security Advisory SA-00924 for the authoritative list of fixed firmware versions per processor family. NetApp customers should consult NTAP-20231221-0008 for platform-specific updates.

Workarounds

Disable or restrict access to BIOS management features that are not required for production operation, where the OEM supports such configuration.
Apply network access controls that prevent low-privilege authenticated users from reaching adjacent network paths to vulnerable platforms.
Enable secure boot, measured boot, and BIOS administrator passwords to reduce the attack surface available to a privilege-escalating actor.

bash

# Verify current BIOS version on Linux
sudo dmidecode -s bios-version
sudo dmidecode -s bios-release-date

# Verify current BIOS version on Windows (PowerShell)
Get-WmiObject -Class Win32_BIOS | Select-Object Manufacturer, SMBIOSBIOSVersion, ReleaseDate

# Compare against the fixed version listed in Intel SA-00924
# Apply the OEM-provided BIOS update package and reboot