Windows Downgrade Attack Risks Exposing Patched Systems to Old Vulnerabilities
Vulnerabilities mentionedAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| CVE-2024-21302 | Summary: As of July 8, 2025 Microsoft has completed mitigations to address this vulnerability. Summary: As of July 8, 2025 Microsoft has completed mitigations to address this vulnerability. See KB5042562: Guidance for blocking rollback of virtualization-based security related updates and the Recommended Actions section of this CVE for guidance on how to protect your systems from this vulnerability. An elevation of privilege vulnerability exists in Windows based systems supporting Virtualization Based Security (VBS), including a subset of Azure Virtual Machine SKUS. This vulnerability enables an attacker with administrator privileges to replace current versions of Windows system files with outdated versions. By exploiting this vulnerability, an attacker could reintroduce previously mitigated vulnerabilities, circumvent some features of VBS, and exfiltrate data protected by VBS. Update: July 10, 2025 Microsoft has addressed this vulnerability for Windows 10 1507, Windows 10, version 1607, Windows 10, version 1809, and Windows Server 2016 and Windows Server 2018. This ensures that mitigations are available to protect all supported versions of Windows 10 and Windows 11 from this vulnerability. See the available mitigations and deployment guidelines described in KB5042562: Guidance for blocking rollback of virtualization-based security related updates. Update: August 13, 2024 Microsoft has released the August 2024 security updates that include an opt-in revocation policy mitigation to address this vulnerability. Customers running affected versions of Windows are encouraged to review KB5042562: Guidance for blocking rollback of virtualization-based security related updates to assess if this opt-in policy meets the needs of their environment before implementing this mitigation. There are risks associated with this mitigation that should be understood prior to applying it to your systems. Detailed information about these risks is also available in KB5042562. Details: A security researcher informed Microsoft of an elevation of privilege vulnerability in Windows 10, Windows 11, Windows Server 2016, and higher based systems including Azure Virtual Machines (VM) that support VBS. For more information on Windows versions and VM SKUs supporting VBS, reference: Virtualization-based Security (VBS) | Microsoft Learn. The vulnerability enables an attacker with administrator privileges on the target system to replace current Windows system files with outdated versions. Successful... See more at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2024-21302 NVD description · AI analysis pending | 6.7 | 2% |
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| CVE-2024-38202 | Summary Microsoft was notified that an elevation of privilege vulnerability exists in Windows Update, potentially enabling an attacker with basic user privilege Summary Microsoft was notified that an elevation of privilege vulnerability exists in Windows Update, potentially enabling an attacker with basic user privileges to reintroduce previously mitigated vulnerabilities or circumvent some features of Virtualization Based Security (VBS). However, an attacker attempting to exploit this vulnerability requires additional interaction by a privileged user to be successful. Microsoft has developed a security update to mitigate this threat which was made available October 08, 2024 and is provided in the Security Updates table of this CVE for customers to download. Note: Depending on your version of Windows, additional steps may be required to update Windows Recovery Environment (WinRE) to be protected from this vulnerability. Please refer to the FAQ section for more information. Guidance for customers who cannot immediately implement the update is provided in the Recommended Actions section of this CVE to help reduce the risks associated with this vulnerability and to protect their systems. If there are any further updates regarding mitigations for this vulnerability, this CVE will be updated and customers will be notified. We highly encourage customers to subscribe to Security Update Guide notifications to receive an alert if an update occurs. Details A security researcher informed Microsoft of an elevation of privilege vulnerability in Windows Update potentially enabling an attacker with basic user privileges to reintroduce previously mitigated vulnerabilities or circumvent some features of VBS. For exploitation to succeed, an attacker must trick or convince an Administrator or a user with delegated permissions into performing a system restore which inadvertently triggers the vulnerability. Microsoft has developed a security update to mitigate this threat which was made available October 08, 2024 and is provided in the Security Updates table of this CVE for customers to download. Note: Depending on your version of Windows, additional steps may be required to update Windows Recovery Environment (WinRE) to be protected from this vulnerability. Please refer to the FAQ section for more information. Guidance for customers who cannot immediately implement the update is provided in the Recommended Actions section of this CVE to help reduce the risks associated with this vulnerability and to protect their systems. If there are any further... See more at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2024-38202 NVD description · AI analysis pending | 7.3 | 2% |
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Full article530 words · extracted from thehackernews.com · click to collapse
Ravie LakshmananAug 08, 2024Windows Security / Vulnerability
Microsoft said it is developing security updates to address two loopholes that it said could be abused to stage downgrade attacks against the Windows update architecture and replace current versions of the operating system files with older versions.
The vulnerabilities are listed below -
- CVE-2024-38202 (CVSS score: 7.3) - Windows Update Stack Elevation of Privilege Vulnerability
- CVE-2024-21302 (CVSS score: 6.7) - Windows Secure Kernel Mode Elevation of Privilege Vulnerability
Credited with discovering and reporting the flaws is SafeBreach Labs researcher Alon Leviev, who presented the findings at Black Hat USA 2024 and DEF CON 32.
CVE-2024-38202, which is rooted in the Windows Backup component, allows an "attacker with basic user privileges to reintroduce previously mitigated vulnerabilities or circumvent some features of Virtualization Based Security (VBS)," the tech giant said.
It, however, noted that an attacker attempting to leverage the flaw would have to convince an Administrator or a user with delegated permissions to perform a system restore which inadvertently triggers the vulnerability.
The second vulnerability also concerns a case of privilege escalation in Windows systems that support VBS, effectively allowing an adversary to replace current versions of Windows system files with outdated versions.
The consequences of CVE-2024-21302 are that it could be weaponized to reintroduce previously addressed security flaws, bypass some features of VBS, and exfiltrate data protected by VBS.
Leviev, who detailed a tool dubbed Windows Downdate, said it could be used to turn a "fully patched Windows machine susceptible to thousands of past vulnerabilities, turning fixed vulnerabilities into zero-days and making the term 'fully patched' meaningless on any Windows machine in the world."
The tool, Leviev added, could "take over the Windows Update process to craft fully undetectable, invisible, persistent, and irreversible downgrades on critical OS components—that allowed me to elevate privileges and bypass security features."
Furthermore, Windows Downdate is capable of bypassing verification steps, such as integrity verification and Trusted Installer enforcement, effectively making it possible to downgrade critical operating system components, including dynamic link libraries (DLLs), drivers, and NT kernel.
The issues, on top of that, could be exploited to downgrade Credential Guard's Isolated User Mode Process, Secure Kernel, and Hyper-V’s hypervisor to expose past privilege escalation vulnerabilities, as well as disable VBS, alongside features like Hypervisor-Protected Code integrity (HVCI).
The net result is that a completely patched Windows system could be rendered susceptible to thousands of past vulnerabilities and turn fixed shortcomings into zero-days.
These downgrades have an added impact in that the operating system reports that the system is fully updated, while simultaneously preventing the installation of future updates and inhibiting detection by recovery and scanning tools.
"The downgrade attack I was able to achieve on the virtualization stack within Windows was possible due to a design flaw that permitted less privileged virtual trust levels/rings to update components residing in more privileged virtual trust levels/rings," Leviev said.
"This was very surprising, given Microsoft's VBS features were announced in 2015, meaning the downgrade attack surface I discovered has existed for almost a decade."
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Text extracted automatically; images, tables and formatting may be missing. Original: https://thehackernews.com/2024/08/windows-downgrade-attack-risks-exposing.html