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
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:
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.
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.