CISA KEV Breakdown
  • October 11, 2022
  • Ryan Cribelar

October 11 – 1 New Vuln | CVE-2022-40684

In this CISA KEV Breakdown, CISA has added one vulnerability to the catalog: a zero-day authentication bypass discovered in Fortinet software within the management interface console. The vulnerability was disclosed last week with a notice from Fortinet to patch affected product versions.

It is important to note that if your organization is still using Fortinet software version 6.x, you are not vulnerable to this attack. The vulnerable versions all appear in patch 7.x.

CVE ID Vendor Software Exploitation Result Due Date EPSS Probability EPSS Percentile GreyNoise Traffic cvssV3
CVE-2022-40684 Fortinet FortiOS, FortiProxy, FortiSwitchManager Authentication Bypass 11/1/2022 0 0 0 9.6

Notable Vulnerability Additions

CVE-2022-40684 | Fortinet Authentication Bypass Vulnerability

Disclosed October 7th in various reports, a Fortinet authentication bypass vulnerability was discovered and dubbed CVE-2022-40684. Word quickly spread relating to the ease of exploitation, as well as the ability to launch the attack unauthenticated at open-facing management consoles. It comes as no surprise to see it find a home in the KEV Catalog.

Accessible in both on-prem and cloud interfaces, it is highly recommended to focus remediation efforts on ensuring your organization is not exploitable to CVE-2022-40684. Fortinet has issued an advisory linked below detailing detection observed from confirmed exploitation, as well as documented mitigation which includes limiting access to the interface console that can be exploited. Nucleus recommends ensuring proper access barriers are in effect for management consoles that require an open-facing placement in the network.

From the advisory below, “Fortinet is aware of an instance where this vulnerability was exploited, and recommends immediately validating your systems against the following indicator of compromise in the device’s logs: user=”local_process_access””

GreyNoise has officially launched a tag page for this particular exploit, and can be observed here.

Security Advisory:

To get a better understanding of each component of our Breakdown, including what we determine to be a notable release, please see our Frequently Asked Questions section below. Also be sure to follow Nucleus Security on Twitter and LinkedIn where we will be posting each time a new Breakdown is released.

← September 30, 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