CVE-2024-38011: Windows 10 1507 Auth Bypass Vulnerability

CVE-2024-38011 Overview

CVE-2024-38011 is a Secure Boot security feature bypass vulnerability affecting multiple versions of Microsoft Windows and Windows Server. The flaw is tied to improper accessible length of a buffer [CWE-130], which allows an attacker on an adjacent network to circumvent Secure Boot integrity checks when a user interacts with the affected system. Microsoft addressed the issue through its July 2024 Patch Tuesday release. Successful exploitation compromises the boot chain, undermining code integrity guarantees that Secure Boot is designed to enforce.

Critical Impact
An attacker who bypasses Secure Boot can load unsigned or malicious boot components, enabling persistent pre-OS implants such as bootkits that survive reinstallation and evade endpoint controls.

Affected Products

Microsoft Windows 10 (versions 1507, 1607, 1809, 21H2, 22H2)
Microsoft Windows 11 (versions 21H2, 22H2, 23H2)
Microsoft Windows Server 2012, 2012 R2, 2016, 2019, 2022, and 2022 23H2

Discovery Timeline

2024-07-09 - CVE-2024-38011 published to the National Vulnerability Database (NVD)
2024-07-09 - Microsoft published the security update guide for CVE-2024-38011
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2024-38011

Vulnerability Analysis

CVE-2024-38011 is categorized as a Secure Boot Bypass vulnerability, rooted in improper handling of a buffer's accessible length [CWE-130]. Secure Boot validates firmware and bootloader components against trusted signatures before allowing them to execute. When length validation is incorrect, an attacker can craft input that the boot-time verification logic mishandles, permitting execution of components that should be rejected. The result is a break in the chain of trust between UEFI firmware and the Windows OS loader. This class of flaw is particularly consequential because it operates below the operating system, before endpoint defenses initialize.

Root Cause

The root cause maps to CWE-130: Improper Handling of Length Parameter Inconsistency. A boot-related component evaluates a buffer using length metadata that does not match the actual accessible size. Microsoft has not published low-level technical details, but the CWE indicates that boundary calculations feeding Secure Boot verification can be manipulated by an attacker-supplied artifact.

Attack Vector

The attack vector is Adjacent Network with user interaction required. An attacker on the same logical network segment must induce a user to trigger the affected code path, for example by staging a malicious boot artifact reachable during startup or update flows. No privileges are required prior to exploitation. Successful exploitation impacts confidentiality, integrity, and availability of the target system.

No public proof-of-concept exploit or in-the-wild exploitation has been reported for CVE-2024-38011, and it is not listed in the CISA Known Exploited Vulnerabilities catalog. See the Microsoft Security Update Guide for authoritative technical details.

Detection Methods for CVE-2024-38011

Indicators of Compromise

Unexpected changes to UEFI variables, boot order, or the contents of the EFI System Partition (ESP).
Unsigned or unknown .efi binaries present in \EFI\Microsoft\Boot\ or other ESP directories.
Windows Event Log entries indicating Secure Boot state changes or measured boot anomalies (TPM PCR mismatches).
Boot Configuration Data (BCD) modifications that reference non-standard loaders.

Detection Strategies

Collect and baseline TPM PCR[0-7] measurements across the fleet and alert on drift indicative of tampered boot components.
Monitor the ESP for file creation, modification, and unsigned binary drops using file integrity monitoring.
Correlate firmware update events, BCD edits, and reboot cycles to surface staged boot-level tampering.

Monitoring Recommendations

Enable Windows Defender System Guard and Measured Boot logging, forwarding attestation data to a central SIEM.
Track deployment status of the July 2024 Windows security updates across every affected Windows and Windows Server SKU.
Alert on Secure Boot being disabled or transitioned to Setup Mode on managed endpoints.

How to Mitigate CVE-2024-38011

Immediate Actions Required

Apply the July 2024 Microsoft security updates to all affected Windows 10, Windows 11, and Windows Server versions listed in the advisory.
Verify Secure Boot is enabled and enforcing on all endpoints and servers via UEFI firmware settings or Confirm-SecureBootUEFI in PowerShell.
Restrict adjacent-network exposure by segmenting management and update networks, and by limiting who can present bootable media or PXE resources.
Educate users to avoid interacting with unsolicited boot media, firmware update prompts, or attached devices from untrusted sources.

Patch Information

Microsoft released fixes for CVE-2024-38011 as part of the July 2024 security update cycle. Refer to the Microsoft Security Update Guide for the specific KB article and build numbers corresponding to each affected Windows and Windows Server version. Apply the update using Windows Update, WSUS, Microsoft Update Catalog, or your enterprise patch management platform.

Workarounds

No official workaround replaces the patch; Microsoft has not published an alternative mitigation for CVE-2024-38011.
As a compensating control, enforce BitLocker with TPM+PIN so that boot-chain tampering triggers recovery-key prompts and blocks silent compromise.
Restrict physical and adjacent-network access to systems that cannot be patched immediately, and monitor them with heightened boot-integrity telemetry.

bash

# Verify Secure Boot status and confirm patch level on Windows
Confirm-SecureBootUEFI
Get-HotFix | Sort-Object -Property InstalledOn -Descending | Select-Object -First 20
Get-CimInstance -ClassName Win32_QuickFixEngineering | Where-Object { $_.HotFixID -like 'KB50*' }