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CISA’s Joint Cybersecurity Advisory: Protecting Your Organization From Vulnerabilities – and 29,000 Other Known Exploits
Some of the world’s leading cybersecurity authorities banded together to co-author the Joint Cybersecurity Advisory: 2021 Top Routinely Exploited Vulnerabilities, where they provided details on CVE vulnerabilities that have been routinely exploited by malicious actors last year.
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Some of the world’s leading cybersecurity authorities banded together to co-author the Joint Cybersecurity Advisory: 2021 Top Routinely Exploited Vulnerabilities, where they provided details on CVE vulnerabilities that have been routinely exploited by malicious actors last year.
These are the top 15 routinely exploited vulnerabilities in 2021:
In addition to these 15, the report also includes an additional 21 vulnerabilities. While many of these issues were disclosed in 2021, a sizable amount range from 2017 – 2020.
- Threat actors are targeting internet-facing systems, such as email servers and virtual private networks (VPNs).
- Threat actors may still be embedded in vulnerable organization’s systems, and may have been undetected for years.
- Relying strictly on the Joint Cybersecurity Advisory and CISA’s KEV Catalog will not adequately protect organizations against nation state hackers and other malicious actors.
Threat actors are targeting internet-facing systems
Log4Shell is the most exploited vulnerability in 2021. While this is not surprising, we need to consider that Log4Shell was discovered on November 30 of last year. It only took one full month for Log4Shell to become the most exploited vulnerability, overtaking every other issue in the Joint CSA, as well as any vulnerability in history.
Aside from Log4Shell, threat actors are targeting various internet-facing systems as can be seen in the multiple ProxyShell and ProxyLogon vulnerabilities affecting Microsoft Exchange Server. In addition, five CVE IDs were dedicated to Accellion File Transfer Appliance, with other entries affecting Windows Print Spooler and Pulse Secure Pulse Connect Secure.
Threat actors may already be embedded in vulnerable systems
According to the Joint CSA, six of its included vulnerabilities were the most routinely exploited in both 2021 and 2020:
| CVE ID | VulnDB ID |
| CVE-2020-1472 | 236054  |
| CVE-2019-11510 | 203753 |
| CVE-2019-18935 | 219449 |
| CVE-2019-19781 | 219857 |
| CVE-2018-13379 | 201631 |
| CVE-2017-11882 | 169255 |
This means that for the past two years, nation state hackers have been taking advantage of flaws from as far back as 2017. This realization becomes even more serious if you compare 2020’s Joint CSA to the more recent CISA’s Known Exploited Vulnerabilities (KEV) Catalog, where all of 2020’s most exploited issues also appear in the CISA KEV.
Flashpoint research shows that multiple nation states have used the six vulnerabilities identified in both 2021’s and 2020’s Joint CSA in past attacks. A few notable groups being Russia’s Federal Security Service (FSB), Iran’s MuddyWater, and China’s Ministry of State Security.
Strictly relying on 2021’s Joint CSA or CISA’s KEV Catalog is not enough
The Joint CSA is a valuable resource for organizations looking to secure their network, but security teams cannot solely base their efforts on it or the CISA KEV.
An oversight of the report is that it does not account for issues without a CVE ID. Fourteen of the issues listed in the 2021 Joint CSA were “Discovered in the Wild”, which is when a vulnerability is discovered via active exploitation, before a regular disclosure can be written, before a vendor is aware of the issue, and before a solution is available. All of these begin as vulnerabilities without CVE IDs.
At time of publication, CVE/NVD has been unable to report over 93,000 vulnerabilities, with many of them being high-to-critical and affecting major products and vendors. The number of zero-day exploits are also rising, suggesting that there is an extremely high chance that threat actors are exploiting non CVE ID vulnerabilities. If this is true, which is highly likely, it means that malicious actors are operating undetected. And as detection improves across the industry, we will likely see even more seemingly sporadic additions to resources like the CISA KEV.
The maintenance of your network and digital assets is just as critical as remediating known exploited vulnerabilities. Organizations must ensure that they are routinely updating their software, operating systems, and other IT assets. Patching will always be essential in maintaining security.
Security teams should start with issues identified in this CSA, but afterwards, they should examine critical and high vulnerabilities that are remotely exploitable – especially if they affect internet-facing assets.
There have been over 29,000 RCE vulnerabilities disclosed since 2017 with known exploits
Given that threat actors are still taking advantage of vulnerabilities from as far as 2017, over 7,600 high-to-critical issues that are RCE with public exploits have been disclosed since 2017. However, CVE-2019-11510 and CVE-2018-13379 had CVSSv2 scores of 5.0 and were among the most routinely exploited. Therefore, organizations cannot relegate “lower” scored RCE issues with public exploits to the backlog.
Considering the possibility that any valid issue fitting the RCE + public exploit criteria could be used in “vulnerability chaining”, organizations now have a risk aperture of more than 29,000 vulnerabilities. And of those, over 11,700 do not have CVE IDs.
Remediate faster with Flashpoint
In order to effectively prioritize and remediate the overwhelming amount of potentially exploitable issues, organizations will need a comprehensive source of vulnerability intelligence. Flashpoint tracks and monitors every vulnerability found in the Joint CSA as well as CISA’s Known Exploited Vulnerabilities Catalog.
Every entry is standardized and contains the latest known details, enabling you to fasttrack remediation. In addition, Flashpoint covers over 287,000 vulnerabilities, including over 93,000 that CVE/NVD fails to report. Sign up for a free trial today to see how better data enables efficient vulnerability management.