This time, Microsoft addressed 129 vulnerabilities: 11 critical and 118 important. In fact, in the file that I exported from the Microsoft website, I saw 2 more CVEs (CVE-2020-1221, CVE-2020-1328) related to Microsoft Dynamics 365 (on-premises). But there is no information on them on the Microsoft website, in the MITRE CVE database and NVD. Does this mean that these CVE ids were mentioned unintentionally and related to some critical issues? I don’t think so, but this is strange.
This time there were no vulnerabilities with detected exploitation, so let’s start with the group “Exploitation more likely” according to Microsoft.
This will be my third Microsoft Patch Tuesday report in video and audio format. And for the third time in a row, Microsoft has addressed over a hundred vulnerabilities. With my Microsoft Patch Tuesday parser, it was possible to generate a report almost on the same day. But, of course, it takes much more time to describe the vulnerabilities manually.
All vulnerabilities: 111
Critical: 16
Important: 95
Moderate: 0
Low: 0
Last time I complained that different VM vendors release completely different reports for Microsoft Patch Tuesday. This time I decided that it’s not a bug, but a feature. I upgraded my script to not only show vulnerabilities, but also show how these vulnerabilities were mentioned in the reports of various VM vendors (Tenable, Qualys, Rapid7 and ZDI). In my opinion, it seems pretty useful.
Making the reviews of Microsoft Patch Tuesday vulnerabilities should be an easy task. All vulnerability data is publicly available. Even better, dozens of reviews have already been written. Just read them, combine and post. Right?
Not really. In fact it is quite boring and annoying. It may be fun to write about vulnerabilities that were already used in some real attacks. But this is a very small part of all vulnerabilities. What about more than a hundred others? They are like “some vulnerability in some component may be used in some attack (or may be not)”. If you describe each of them, no one will read or listen this.
You must choose what to highlight. And when I am reading the reports from Tenable, Qualys and ZDI, I see that they choose very different groups of vulnerabilities, pretty much randomly.
My classification script
That’s why I created a script that takes Patch Tuesday CVE data from microsoft.com and visualizes it giving me helicopter view on what can be interesting there. With nice grouping by vulnerability type and product, with custom icons for vulnerability types, coloring based on severity, etc.
Without a doubt, the hottest Microsoft vulnerability in March 2020 is the “Wormable” Remote Code Execution in SMB v3 CVE-2020-0796. The most commonly used names for this vulnerability are EternalDarkness, SMBGhost and CoronaBlue.
There was a strange story of how it was disclosed. It seems like Microsoft accidentally mentioned it in their blog. Than they somehow found out that the patch for this vulnerability will not be released in the March Patch Tuesday. So, they removed the reference to this vulnerability from the blogpost as quickly as they could.
But some security experts have seen it. And, of course, after EternalBlue and massive cryptolocker attacks in 2017, each RCE in SMB means “OMG, this is happening again, we need to do something really fast!” So, Microsoft just had to publish an advisory for this vulnerability with the workaround ADV200005 and to release an urgent patch KB4551762.
IMHO, these are the two most interesting vulnerabilities in a recent Microsoft Patch Tuesday February 2020:
Mysterious Windows RCE CVE-2020-0662. “To exploit the vulnerability, an attacker who has a domain user account could create a specially crafted request, causing Windows to execute arbitrary code with elevated permissions.” Without needing to directly log in to the affected device!
Microsoft Exchange server seizure CVE-2020-0688. By sending a malicious email message the attacker can run commands on a vulnerable Exchange server as the system user (and monitor email communications). “the attacker could completely take control of an Exchange server through a single e-mail”.
There were also RCEs in Remote Desktop (Client and Service), a third attempt to fix RCEs in Internet Explorer, Elevation of Privilege, etc. But all this stuff we see in almost every Patch Tuesday and without fully functional exploits it’s not really interesting. 🙂
Read the full reviews in Tenable and Zero Day Initiative blogs.
I recently figured out how to work with Microsoft Active Directory using Python 3. I wanted to get a hierarchy of Organizational Units (OUs) and all the network hosts associated with these OUs to search for possible anomalies. If you are not familiar with AD, here is a good thread about the difference between AD Group and OU.
It seems much easier to solve such tasks using PowerShell. But it will probably require a Windows server. So I leave this for the worst scenario. 🙂 There is also a PowerShell Core, which should support Linux, but I haven’t tried it yet. If you want to use Python, there is a choice from the native python ldap3 module and Python-ldap, which is a wrapper for the OpenLDAP client. I didn’t find any interesting high-level functions in Python-ldap and finally decided to use ldap3.
My last post about Guinea Pigs and Vulnerability Management products may seem unconvincing without some examples. So, let’s review one. It’s a common problem that exists among nearly all VM vendors, I will demonstrate it on Tenable Nessus.
And, as you can see, it has formalized “Risk Information” data in the right column. There is only one CVSS score and vector, one CPE, one exploitability flag, one criticality level. Probably because of architectural limitations of the scanner. So, two very simple questions:
for which CVE (of these 23) is this formalized Risk Information block?
for which CVE (of these 23) exploit is available?
Ok, maybe they show CVSS for the most critical (by their logic) CVE. Maybe they somehow combine this parameter from data for different CVEs. But in most cases this will be inaccurate. Risk information data for every of these 23 vulnerabilities should be presented independently.
As you can see on the screenshot, one of these vulnerabilities is RCE the other is Information Disclosure. Vulnerability Management solution tells us that there is an exploit. Is this exploit for RCE or DoS? You should agree, that it can be crucial for vulnerability prioritization. And more than this, in the example there are 7 different RCEs in Internet Explorer, MSXML parser, Windows Hyper-V, etc. All this mean different attack scenarios. How is it possible to show it Vulnerability Scanner like one entity with one CVSS and exploitability flag? What can the user get from this? How to search in all this?
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