Our researchers discovered a vulnerability on all Windows Workstation and Server versions from Windows 7 and Server 2008 R2 to the latest Windows 11 v24H2 and Server 2022. The vulnerability allows an attacker to obtain user's NTLM credentials by simply having the user view a malicious file in Windows Explorer - e.g., by opening a shared folder or USB disk with such file, or viewing the Downloads folder where such file was previously automatically downloaded from attacker's web page.
We reported this issue to Microsoft, and - as usual - issued micropatches for it that will remain free until Microsoft has provided an official fix.
We are withholding details on this vulnerability until Microsoft's fix becomes available to minimize the risk of malicious exploitation.
This is the third 0day we have recently found and reported to Microsoft, after the Windows Theme file issue (still a 0day without an official patch) and the Mark of the Web issue on Server 2012 (also still a 0day without an official patch).
In addition, the "EventLogCrasher" vulnerability, allowing an attacker to disable all Windows event logging on all domain computers (reported to Microsoft in January this year by security researcher Florian), is still waiting for an official patch so our patches for it are the only ones available.
There are also currently three NTLM-related publicly known "wont fix" vulnerabilities that Microsoft decided not to patch with 0patch patches available: PetitPotam, PrinterBug/SpoolSample and DFSCoerce. All of these are present on all latest fully updated Windows versions, and if your organization is using NTLM for any reason, it could be affected.
Currently, 40% of our users are using 0patch for protection against 0day and "wont fix" vulnerabilities, while others use 0patch for keeping their legacy Windows systems and Office versions secure with our security patches.
Micropatch Availability
Since
this is a "0day" vulnerability with no official vendor fix available,
we are providing our micropatches for free until such fix becomes
available.
Micropatches were written for:
Legacy Windows versions:
- Windows 11 v21H2 - fully updated
- Windows 10 v21H2 - fully updated
- Windows 10 v21H1 - fully updated
- Windows 10 v20H2 - fully updated
- Windows 10 v2004 - fully updated
- Windows 10 v1909 - fully updated
- Windows 10 v1809 - fully updated
- Windows 10 v1803 - fully updated
- Windows 7 - fully updated with no ESU, ESU 1, ESU 2 or ESU 3
- Windows Server 2012 - fully updated with no ESU or ESU 1
- Windows Server 2012 R2 - fully updated with no ESU or ESU 1
- Windows Server 2008 R2 - fully updated with no ESU, ESU 1, ESU 2, ESU 3 or ESU 4
Windows versions still receiving Windows Updates:
- Windows 11 v24H2 - fully updated
- Windows 11 v23H2 - fully updated
- Windows 11 v22H2 - fully updated
- Windows 10 v22H2 - fully updated
- Windows Server 2022 - fully updated
- Windows Server 2019 - fully updated
- Windows Server 2016 - fully updated
- Windows Server 2012 fully updated with ESU 2
- Windows Server 2012 R2 fully updated with ESU 2
Micropatches have already been distributed to, and applied on, all affected online computers with 0patch Agent in PRO or Enterprise accounts (unless Enterprise group settings prevented that).
Vulnerabilities like these get discovered on a regular basis, and
attackers know about them all. If you're using Windows that aren't
receiving official security updates anymore, 0patch will make sure these
vulnerabilities won't be exploited on your computers - and you won't
even have to know or care about these things.
If you're new to 0patch, create a free account in 0patch Central, start a free trial, then install and register 0patch Agent. Everything else will happen automatically. No computer reboot will be needed.
Did
you know 0patch will security-adopt Windows 10 when it goes out of
support in October 2025, allowing you to keep using it for at least 5
more years? Read more about it here.
To learn more about 0patch, please visit our Help Center.
