June 22, 2023 CISA KEV Breakdown | VMware, Roundcube, Mozilla, Microsoft

June 22: 6 New Vulns | CVE-2023-20887, CVE-2021-44026, CVE-2020-35730, CVE-2020-12641, CVE-2016-9079, CVE-2016-0165

In this CISA KEV Breakdown, six vulnerabilities were added to the CISA KEV catalog. Two come back from the past being Firefox and Win32k vulnerabilities from 2016, as well as three more-recent Roundcube vulnerabilities that were part of Russian threat actor’s targeting of Ukrainian Government entities, and finally a vulnerability in VMware Aria from this year.

Notable Vulnerability Additions

CVE-2023-20887 | VMware Aria Command Injection

A vulnerability in VMware Aria allows for an attacker to achieve command injection when accepting user input through the Apache Thrift RPC interface. This vulnerability can be exploited remotely, and there are multiple proof-of-concepts available publicly. It can be successfully exploited when an attacker sends a malicious payload to the /saas./resttosaasservlet endpoint on a vulnerable system. Read more about the initial disclosure, as well as discovery and proof-of-concept from Summoning Team here.

According to user @Y4er_ChaBug on Twitter, this vulnerability exploit is actually a workaround to the patch applied for CVE-2022-31702, and this appears to be true given the technical details of both vulnerabilities.

GreyNoise has launched a tag to track exploitation and scanning activity surrounding CVE-2023-20887, as well as a blog. Below is an example packet containing the RCE attempt from the GreyNoise blog.

Security Advisory(s):

https://www.vmware.com/security/advisories/VMSA-2023-0012.html

CVE-2021-44026, CVE-2020-12641, CVE-2020-35730 | Roundcube Vulnerabilities

Recorded Future’s Insikt Group reported on June 20 in partnership with the Ukraine’s Computer Emergency Response Team a campaign targeting high-profile entities in Ukrainian government. The campaign consisted of separate highly sophisticated spearphishing emails against public-facing vulnerable Roundcube servers, as well as the exploitation of CVE-2023-23397 on edge devices to obtain further access that led to initial compromise.

Once gaining a foothold, the attackers would leverage further Roundcube exploits to exfiltrate data from Roundcube. The campaign has been linked to a historical actor dubbed BlueDelta which utilized CVE-2023-23397 in campaigns targeting the European sector as well as Ukraine.

CVE-2020-35730 is used initially to exploit vulnerable Roundcube email servers due to a link reference mishandling in rcube_string_replacer.php. The attack-chain attempts to utilize both this and CVE-2020-13965 as means of gaining further access into vulnerable Roundcube devices. Once further compromised, the attackers can then leverage CVE-2021-44026, a SQL injection vulnerability to exfiltrate data from the mail server.

While these campaigns have been primarily focused on European sectors according to interest from BlueDelta activity, it is encouraged for all organizations to assess their exposed perimeter devices for remotely exploitable vulnerabilities such as these Roundcube vulnerabilities.

Security Advisory(s):

CVE-2020-12641: https://roundcube.net/news/2020/04/29/security-updates-1.4.4-1.3.11-and-1.2.10

CVE-2020-35730: https://roundcube.net/news/2020/12/27/security-updates-1.4.10-1.3.16-and-1.2.13

CVE-2021-44026: https://roundcube.net/news/2021/11/12/security-updates-1.4.12-and-1.3.17-released

CVE-2016-0165 | Microsoft Win32k Privilege Escalation

A vulnerability exists in Win32k, specifically the win32kbase.sys driver component, which calculates a value in a struct represented by a 64 bit value, but is then placed in a 32 bit register, resulting in a potential for overflow to occur. To exploit the vulnerability, an attacker would first need to gain local access to the machine. Exploit code has existed publicly for nearly as long as it’s date of disclosure.

The vulnerability was uncovered as a 0-day and reported as exploited in the wild in Google Threat Analysis Group’s (TAG) 0day Tracker Sheet. Since exploitation activity as well as a patch have been known for quite some time, this vulnerability was reported to CISA by Nucleus’ own Patrick Garrity and suggested it be added to the KEV due to meeting the required criteria.

Security Advisory(s):

https://learn.microsoft.com/en-us/security-updates/securitybulletins/2016/ms16-039

CVE-2016-9079 | Mozilla Firefox & Thunderbird Use-After-Free

A vulnerability exists in Firefox before version 50.0.2, Firefox ESR before version 45.5.1, and Thunderbird before version 45.5.1 that can allow an attacker to execute code. An attacker would first need to convince a user, likely through the use of social engineering, to interact with a malicious application crafted by the attacker. It was reported around date of disclosure that this vulnerability was primarily exploited as a means to identify information on users behind Tor browsers, since Tor is based on Firefox. See this extensive writeup on the discovery and technical details behind the vulnerability from Rapid7 here. This vulnerability was also referenced in having been exploited in the wild in Google TAG’s 0day Tracker Sheet.

Since exploitation activity as well as a patch has been known for quite some time, this vulnerability was reported to CISA by Nucleus’ own Patrick Garrity and suggested it be added to the KEV due to meeting the required criteria.

Security Advisory(s):

https://www.mozilla.org/en-US/security/advisories/mfsa2016-92/#CVE-2016-9079

Footnote – CVE-2023-20867

Nucleus Security is also aware of CVE-2023-20867 which is a VMware ESXi 0-day that has been confirmed as exploited by Mandiant. They report in their blog that a novel malware system developed by UNC3886 was used to backdoor VMware ESXi hosts, vCenter servers and Windows virtual machines. The exploitation of CVE-2023-20867 was sophisticated and executed under the noses of EDR for quite some time. As of recently, a fix has been available by the VMware team, as well as SUSE. Organizations are encouraged to assess impact from this vulnerability as we predict that is likely to be added to the KEV soon.

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