Here we plan to announce vulnerabilities we consider relevant to ourself or our customers. Mostly to announce that we are at least aware of these vulnerabilities, in case you wondered. Maybe you find there is an overlap with vulnerabilities you should be aware of yourself?

This might not be an extensive list, but is performed at best effort.

ADV200006 | Type 1 Font Parsing Remote Code Execution Vulnerability

Published: 2020-03-23
MITRE CVE-2020- (TBD)

Microsoft is warning about a vulnerability they have detected used in targeted attacks and that there is no patch for yet. No patch and detected in use, a place for the scary word “zero-day”, but this is not a tabloid.

“Two remote code execution vulnerabilities exist in Microsoft Windows when the Windows Adobe Type Manager Library improperly handles a specially-crafted multi-master font – Adobe Type 1 PostScript format.” This would not be so exciting if not document formats had the feature of including their own fonts in documents.

“There are multiple ways an attacker could exploit the vulnerability, such as convincing a user to open a specially crafted document or viewing it in the Windows Preview pane.”

This affects Windows 10 (but read on), and all Windows Server from 2008 until 2019. Windows 10 has some mitigating features. As always, read the advisory for full details.

There exist no official patch for this as of now. There are some mitigations possible, like “Disable the Preview Pane and Details Pane in Windows Explorer”, “Disable the WebClient service” (WebDAV) and “Rename ATMFD.DLL”. Basefarm has not tested these and recommend everyone to have a test environment that resembles their production environment and test the mitigations before applying them.

Consider the usage of your servers, are there documents viewed on them? Are the documents from an unknown, potentially untrusted source? Do you value the integrity of that server and all it in turn has access too? It might be worth to consider implementing the mitigations. For many servers this use case is not a match and it is potentially better to wait for an official and tested patch.

Basefarm follows this vulnerability internally as BF-VLN-2011507 and asking our dedicated customer teams to follow up these recommendations.

CVE-2020-0852 | Microsoft Word Remote Code Execution Vulnerability

Published: 2020-03-10
MITRE CVE-2020-0852

“A remote code execution vulnerability exists in Microsoft Word software when it fails to properly handle objects in memory. An attacker who successfully exploited the vulnerability could use a specially crafted file to perform actions in the security context of the current user. For example, the file could then take actions on behalf of the logged-on user with the same permissions as the current user.”

This vulnerability was overshadowed by the SMBv3 remote code execution vulnerability “announced” at the same time, as we have written about earlier. Basefarm evaluated this to be just as likely, if not more, to cause major infections in a corporate environment. It requires some user action to successfully exploit, but opening a document is not an action most users considers risky.

Basefarm recommends applying this patch as soon as possible, even though there is no known exploitation and no proof of concept published, because if a campaign starts up exploiting this on a Friday afternoon you will not have enough time to react.

This affects Microsoft Office (certain versions) AND Sharepoint Server 2019.
Basefarm is tracking this internally as BF-VLN-2004690.

CVE-2020-0796 | Server Message Block 3.0 (SMBv3) Remote Code Execution

Published: 2020-03-10
MITRE CVE-2020-0796

As of writing, Microsoft has not released any official information, but FortiGuard writes that there exists a “(…) Buffer Overflow Vulnerability in Microsoft SMB Servers. The vulnerability is due to an error when the vulnerable software handles a maliciously crafted compressed data packet. A remote, unauthenticated attacker can exploit this to execute arbitrary code within the context of the application.”

And as affected products FortiGuard mentions Windows 10, and Semi-Annual Channel (Windows Server 1903 and 1909). But as Microsoft has not released any official information this might be subject to change.

Basefarm does not recommend anyone to expose SMB and port 445 to an untrusted network. There also exists unofficial mitigation by adding a registry key to disable compression on the SMBv3 protocol. Basefarm is following the developments here, but as of writing there is no known proof of exploit or exploitation in the wild, there is also no official fix for this vulnerability.

Update 2020-03-11:

Microsoft has now released an advisory where they confirm previously known details and adds “to exploit the vulnerability against an SMB Client, an unauthenticated attacker would need to configure a malicious SMBv3 Server and convince a user to connect to it.”

So this vulnerability is more of a client-issue than a server issue. The known workaround to disable compression in SMBv3 prevents exploitation against an SMB Server, not an SMB Client.

Still no official fix, no known exploitation in the wild and no proof of concept available.

Basefarm is tracking this is a client issue in BF-VLN-2003557 and will most likely force all our clients to install this as soon as an official fix is available. We recommend others do too.

CVE-2020-0688 | Microsoft Exchange Validation Key Remote Code Execution Vulnerability

Published: 02/11/2020 | Last Updated : 02/11/2020
MITRE CVE-2020-0688

“A remote code execution vulnerability exists in Microsoft Exchange Server when the server fails to properly create unique keys at install time.

Knowledge of a the validation key allows an authenticated user with a mailbox to pass arbitrary objects to be deserialized by the web application, which runs as SYSTEM.

The security update addresses the vulnerability by correcting how Microsoft Exchange creates the keys during install.”

Zero Day Initiative recently published a write-up about this vulnerability, and some key points to know is “Instead of having randomly-generated keys on a per-installation basis, all installations of Microsoft Exchange Server have the same validationKey and decryptionKey values in web.config. These keys are used to provide security for ViewState.” and “Due to the use of static keys, an authenticated attacker can trick the server into deserializing maliciously crafted ViewState data. With the help of YSoSerial.net, an attacker can execute arbitrary .NET code on the server in the context of the Exchange Control Panel web application, which runs as SYSTEM.”

So this is bad. On the bright side it requires an authenticated user, but considering the amount of leaked credentials these days it could be better.

We agree with Zero Day Initiative when they say “if you’re an Exchange Server administrator, you should treat this as a Critical-rated patch and deploy it as soon as your testing is complete. Microsoft lists this with an Exploit Index of 1, which means they expect to see exploits within 30 days of the patch release. As demonstrated, that certainly seems likely.”

Update 2020-03-04: Exploit for this vulnerability is now a part of the metasploit framework and exploitation is very easy, just needs any domain user.

Internally Basefarm is tracking this as BF-VLN-1994667.

CVE-2020-1938 – Apache Tomcat AJP Request Injection and potential Remote Code Execution

Published by Apache: 2020-02-24
MITRE CVE-2020-3158

“When using the Apache JServ Protocol (AJP), care must be taken when trusting incoming connections to Apache Tomcat. Tomcat treats AJP connections as having higher trust than, for example, a similar HTTP connection. If such connections are available to an attacker, they can be exploited in ways that may be surprising.”

There is not enough details available yet, but the vulnerability has at least a CVSS Base score of 8.1, High. This depends on how hard it is to exploit, etc.

There is proof of concept published, but as of writing no known public exploitation of this vulnerability.

Basefarm customers will be upgraded as part of normal patching routines.

CVE-2020-3158 – Cisco Smart Software Manager On-Prem Static Default Credential Vulnerability

Published by Cisco: 2020-02-19
MITRE CVE-2020-3158

“A vulnerability in the High Availability (HA) service of Cisco Smart Software Manager On-Prem could allow an unauthenticated, remote attacker to access a sensitive part of the system with a high-privileged account.”

The vulnerability has a CVSS Base score of 9.8, Critical.

Basefarm has triaged this vulnerability and found that we are not using the Cisco Smart Software Manager On-Prem software. Basefarm will not track this vulnerability further.

VMSA-2020-0003 vRealize Operations for Horizon Adapter updates address multiple security vulnerabilities (CVE-2020-3943, CVE-2020-3944, CVE-2020-3945)

Published by VMware: 2020-02-18
MITRE CVE-2020-3943

“vRealize Operations for Horizon Adapter uses a JMX RMI service which is not securely configured. VMware has evaluated the severity of this issue to be in the Critical severity range with a maximum CVSSv3 base score of 9.0.”

“vRealize Operations for Horizon Adapter has an improper trust store configuration leading to authentication bypass. VMware has evaluated the severity of this issue to be in the Important severity range with a maximum CVSSv3 base score of 8.6.”

“vRealize Operations for Horizon Adapter contains an information disclosure vulnerability due to incorrect pairing implementation between the vRealize Operations for Horizon Adapter and Horizon View. VMware has evaluated the severity of this issue to be in the Moderate severity range with a maximum CVSSv3 base score of 5.3.”

The issue has been evaluated by our VMware technicians and Basefarm has concluded that we do not use Horizon Adapter and our systems are therefor not affected by these vulnerabilities.

ThemeREX Addons – Remote Code Execution (0day, Being Exploited)

Published by Wordfence: 2020-02-18
No known CVE

“This flaw allows attackers to remotely execute code on a site with the plugin installed, including the ability to execute code that can inject administrative user accounts.
This vulnerability has not yet been patched. We are only trying to get the word out so people can remove the plugin temporarily as the vulnerability is being actively exploited. ”

Basefarm considers this a Base CVSS Score: 9.8 (Critical) – there is no fix and it is currently being actively exploited.

Basefarm has done some initial investigations regarding the use of this WordPress Theme, but has not identified any customers or internal usage. Basefarm has decided not to track this vulnerability further internally, but want to make it visible by posting this vulnerability bulletin.

CVE-2020-0618 | Microsoft SQL Server Reporting Services Remote Code Execution Vulnerability

Published by Microsoft: 02/11/2020
MITRE CVE-2020-0618

“A remote code execution vulnerability exists in Microsoft SQL Server Reporting Services when it incorrectly handles page requests. An attacker who successfully exploited this vulnerability could execute code in the context of the Report Server service account.”

There exists a proof of concept and write-up.

Basefarm considers this a Base CVSS Score: 9.8 (Critical) – but there exists an official fix from Microsoft, bringing the Temporal CVSS Score down to a 9.4 (Critical).

And we consider most of our users do not expose Microsoft SQL Server Reporting Service directly to the internet, so this CVSS Environmental Score can be lowered down to a 7.6 (High).

Per Basefarm Vulnerability process we still consider this a priority 1 (of 3) issue, and we will not wait until normal patch window to mitigate this issue. Internally we are tracking this progress in BF-VLN-1990987, registered 2020-02-18.