Exploits & Vulnerabilities
"Zerologon” Understanding the Issues and Applying Solutions
A new CVE was released recently that has made quite a few headlines
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A new CVE was released recently that has made quite a few headlines – CVE-2020-1472. Zerologon, as it’s called, may allow an attacker to take advantage of the cryptographic algorithm used in the Netlogon authentication process and impersonate the identity of any computer when trying to authenticate against the domain controller.
To put that more simply, this vulnerability in the Netlogon Remote Protocol (MS-NRPC) could allow attackers to run their applications on a device on the network. An unauthenticated attacker would use MS-NRPC to connect to a Domain Controller (DC) to obtain administrative access.
According to Dustin Childs with Trend Micro’s Zero Day Initiative (ZDI), “What’s worse is that there is not a full fix available. This patch enables the DCs to protect devices, but a second patch currently slated for Q1 2021 enforces secure Remote Procedure Call (RPC) with Netlogon to fully address this bug. After applying this patch, you’ll still need to make changes to your DC. Microsoft published guidelines to help administrators choose the correct settings.”
But if there’s a patch, why is this a big deal?
You might be thinking, “Well if there’s a patch, this really isn’t an issue.” But the idea of “just patch it” is not as easy as it sounds – check out this post (also from Dustin with the ZDI) for more insights on barriers to patching.
The average Mean Time to Patch (MTTP) is 60 to 150 days. This CVE was published in early August, so that would put the average time for implementing this patch between October 2020 and January 2021.
You have maybe heard the security industry joke that after Patch Tuesday comes Exploit Wednesday. That’s the comedic way to suggest that after a batch of patches for new CVEs are released the first Tuesday of every month from Microsoft and Adobe, attackers get to work reversing the patches to write exploits to take advantage of the bugs before patches have been applied.
Given the MTTP, that’s 2-5 months that your organisation is left exposed to a known threat.
So what can I do to protect my organisation?
Fortunately, there are advanced protections available for organisations to stay protected, including virtual patching. This provides an extra layer of security to help protect against vulnerabilities before you apply the official vendor patch. As the name suggests, it’s very similar to a patch because it is specifically designed to protect your environment with intrusion protection system (IPS) capabilities in case someone attempted to exploit that vulnerability. In general, virtual patches can be a critical safety net to allow you to patch in the way that works for your organisation.
With Trend Micro, our virtual patching technology helps you mitigate attacks focused on thousands of vulnerabilities, giving you the flexibility to patch regularly without breaking your operational processes for every emergency patch. Other features, such as log inspection, also help you get valuable insight into post-patch exploitation attempts on your network even after you have fully patched. To learn more about Trend Micro protection for CVE-2020-1472, read our knowledge base article here.