While the patch works on both 32- and 64-bit versions of Server 2003, ACROS Security cautioned that it was meant to fix a particular version of the dynamic link library that needed to be patched — httpext.dll version 6.0.3790.4518 — and asked those who used the patch to check the version of this library on their systems before doing so.
IIS 6.0 gets installed with Windows Server 2003, a version of Windows that is no longer supported by Microsoft. Support ended on 14 July 2015 and given this, the software giant has chosen not to issue a patch.
With about 600,000 servers estimated to be running IIS 6.0, the need to patch became urgent after Chinese researchers released proof-of-concept exploit code for a zero-day buffer overflow.
The PROPFIND method would retrieve properties defined on the resource identified by the Request-URI. This is something that all WebDAV-Compliant resources must support.
WebDAV is an extension of the HTTP protocol that simplifies sharing and content authoring.
ACROS Security's Renata Stupar told iTWire that the company's 0patch team had created a micropatch to fix this vulnerability.
"You have probably heard of the recent exploit for the end-of-support Windows Server 2003 that can allow a remote attacker to execute arbitrary code on the server," Stupar said.
"There are still more than 600,000 such servers on the Internet, and they will not receive a patch from Microsoft. Our company has created a free micropatch for this vulnerability.
"As such, this is the only patch available in the world for this vulnerability, which will likely start getting exploited now that Metasploit also has an exploit module for it."
Mitja Kolsek of the 0patch team has a detailed account of the vulnerability and the patch that was created.
In part, he wrote, "Fortunately, most 2003 servers don't have WebDAV functionality enabled, but it is likely enabled on many SharePoint Portal servers and sites that use it for remote Web authoring or similar.
"(Researcher) Iraklis Mathiopoulos ran a sample probe to determine how many Internet-connected 2003 servers are WebDAV-enabled and found that approximately 10% of them are. So we seem to have about 60,000 servers out there exposed to this freshly published exploit.
Kolsek, said to help maintainers of Windows Server 2003 boxes block almost inevitable attacks, "we decided to provide them a free solution: a micropatch for CVE-2017-7269, which they can apply on their machines not only without rebooting, but also without even restarting Internet Information Server. (For those new to 0patch, this is how we believe applying security patches should always look like.)"