CISA KEV Breakdown
  • November 10, 2022
  • Ryan Cribelar

November 9 – 7 New Vulns | 7 Zero-Days

In this CISA KEV Breakdown, CISA has added seven vulnerabilities. Four of them being additions from Microsoft’s patch Tuesday in which six exploited zero-days were issued patches, including updates to ProxyNotShell (CVE-2022-41040 and CVE-2022-41082). The last three added to the KEV include an exploit-chain on Samsung devices discovered as a zero-day and patched in 2021. Kernel exploits continue to play a large role in new zero-day discoveries as well as involvement with the spyware industry.

wdt_ID CVE ID Vendor Software Exploitation Result GreyNoise Traffic EPSS Probability EPSS Percentile CVSSv3 Due Date
1 CVE-2022-41128 Microsoft Windows Remote Code Execution 8.8 11/29/2022
2 CVE-2022-41073 Microsoft Windows Privilege Escalation 7.8 11/29/2022
3 CVE-2022-41125 Microsoft Windows Privilege Escalation 7.8 11/29/2022
4 CVE-2021-25337 Samsung Mobile Devices Arbitrary File Read/Write 0.00885 26.838 7.1 11/29/2022
5 CVE-2022-41091 Microsoft Windows Mark of the Web Bypass 5.4 11/29/2022
6 CVE-2021-25370 Samsung Mobile Devices Information Leak 0.00885 26.838 4.4 11/29/2022
7 CVE-2021-25369 Samsung Mobile Devices Arbitrary Kernel Read/Write 0.00885 26.838 5.5 11/29/2022
CVE ID Vendor Software Exploitation Result GreyNoise Traffic EPSS Probability EPSS Percentile CVSSv3 Due Date

Notable Vulnerability Additions

CVE-2022-41128, CVE-2022-41073, CVE-2022-41125, CVE-2022-41091 | Microsoft Patch Tuesday Zero-Days

Four of the six zero-day exploits released in Microsoft’s Tuesday update find themselves on the KEV. When deciding whether to immediately apply the patch across your environment, it may be wise to caution most critical devices when applying the patch for the two CVEs related to ProxyNotShell as it has received some buzz amongst the security community to come with pain-points. It is always safe to tread carefully on mission-critical hardware compared to user-machines and non-critical devices when applying a large security update such as this, including 68 different CVE fixes.

CVE-2022-41128 can be considered the more critical zero-day flaw fixed in this round of additions to the KEV, as one can argue it takes less effort from an attacker to allow for successful exploitation. Per the Microsoft update guide for the vulnerability, “An attacker would have to host a specially crafted server share or website. An attacker would have no way to force users to visit this specially crafted server share or website, but would have to convince them to visit the server share or website, typically by way of an enticement in an email or chat message.” This means that users would have to do as little as visit a malicious landing page in order for the vulnerability to be exploited by the attacker, leaving this open as a prime candidate for phishing and social engineering attacks.

CVE-2022-41073 and CVE-2022-41125 both include code execution which can be leveraged for SYSTEM-level access, however are offset in criticality due to the access as well as effort required to successfully exploit.

CVE-2022-41091 can be leveraged by a remote attacker to execute code. To leverage exploitation would require a specially crafted JavaScript file which is interacted with by an elevated user on the system. Although it can be considered less critical due to the requirement in administrator privileges, the vulnerability resembles characteristics similar to techniques observed by HP’s Threat Research team in the Magniber ransomware campaign in October of this year. The attack involved utilizing JavaScript files to distribute the malware.

Security Advisory:

CVE-2021-25337, CVE-2021-25370, CVE-2021-25369 | Samsung Clipboard Exploit-Chain

Three of the vulnerabilities added to KEV November 9 are belonging to an exploit-chain written about by Google’s Project Zero as A Very Powerful Clipboard. To emphasize, these vulnerabilities were discovered and patched in 2021, and therefor Samsung devices under regular cadence for updates by the user should long be remediated and the security update from Samsung has been linked below. The vulnerabilities were uncovered in custom components adopted by Samsung, revealing the fact that core functionality, such as the Linux kernel, are not affected by these vulnerabilities.

According to evidence obtained in Project Zero’s reporting, their Threat Analysis Group (TAG) believes the sample to be attributed to surveillance vendors involved in the spyware industry. They reference similar tactics observed in previous work TAG has published relating to evidence of exploitation resulting from spyware providers targeting users in Italy and Kazakhstan in June of this year. Read more from the report to better understand behaviors and activity relating to spyware vendors tracked by TAG.

Security Advisory:

Be sure to check out Nucleus Security’s KEV Enrichment Dashboard where we overlay vulnerabilities that are added to the catalog with intelligence from GreyNoise, exploit-prediction scoring from EPSS and lastly CVSS. You can use the data yourself and use further metrics to influence decision-making when determining risk of vulnerabilities added to the KEV.

← October 28, 2022 CISA Kev Breakdown

Click here to expand our CISA KEV Breakdown Frequently Asked Questions
  • What makes for a notable addition?
    • A notable addition can arise from many different characteristics. If a particular vulnerability is notable to the security community or a subset of the security community or if the EPSS score reveals notable information about the vulnerability, this can constitute further analysis. It may also be the case that a particular vulnerability shines a light on everyday users and we will highlight important information and key takeaways to ensure users and readers have easy access to actionable information.
  • When is the Breakdown released?
    • We aim to have our analysis of each KEV update posted within 24 hours of the time in which the Catalog is updated. See CISA’s full catalog here
  • I am not bound by BOD 22-01 or federal regulations, why should the KEV concern me?
    • CISA encourages all organizations to utilize the Catalog as an attribute in your vulnerability prioritization framework. Organizations looking to lessen the scope on known dangerous vulnerabilities and make a goal to remediate them can understand where they currently stand against what CISA has confirmed as exploited vulnerabilities in the wild. See CISA’s section on “How should organizations use the KEV catalog?” here.
  • What is EPSS?
    • EPSS is the Exploit Prediction Scoring System. It is an open, data-driven effort for estimating the likelihood (probability) that a software vulnerability will be exploited in the wild. See the EPSS home page on FIRST for more information here.
  • What is the difference between EPSS probability and EPSS percent?
    • EPSS probability is the risk calculated by the model when determining the perceived threat of the vulnerability itself. Percentage is a relative comparison of the rest of the CVEs within the given sample. While the probability only changes upon refreshing the results from the model, the percentage can change purely based on the CVE sample given. In the case of the Breakdown, we use the percentage given by the pool of all CVEs with given EPSS data. Scores may vary post-release of the post given new information about the vulnerabilities and their perceived threat. For more information on applying and understanding EPSS data, see this article on the FIRST website, as well as their FAQ page.
  • What is GreyNoise?
    • GreyNoise is a platform that collects, analyzes, and labels data on IPs that scan the internet and saturate security tools with noise. Through their sensor network, GreyNoise observes vulnerability exploitation attempts for vulnerabilities that are exploited in the wild over the Internet. These are arguably vulnerabilities that should be at the very top of your priority list to remediate.
  • Why are GreyNoise exploitation attempts only observed on ~20% of KEV vulnerabilities?
    • Exploitation of many vulnerabilities in the CISA KEV will not be observed for many reasons that GreyNoise does a good job of explaining in this post. For example:
      • The vulnerability may not be remotely exploitable
      • Vulnerability exploitation may require authentication (and result in privilege escalation)
      • The impacted software may not be exposed to the internet
      • Mass scanning/exploitation is not occurring yet