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CISA published 2021 Top 15 most exploited software vulnerabilities

Cybersecurity and Infrastructure Security Agency (CISA) published a list of 2021’s top 15 most exploited software vulnerabilities

Cybersecurity and Infrastructure Security Agency (CISA) published the list of 2021’s top 15 most exploited software vulnerabilities

This joint Cybersecurity Advisory (CSA) was coauthored by cybersecurity agencies of the United States, Australia, Canada, New Zealand, and the United Kingdom: the Cybersecurity and Infrastructure Security Agency (CISA), National Security Agency (NSA), Federal Bureau of Investigation (FBI), Australian Cyber Security Centre (ACSC), Canadian Centre for Cyber Security (CCCS), New Zealand National Cyber Security Centre (NZ NCSC), and United Kingdom’s National Cyber Security Centre (NCSC-UK). This advisory also includes other frequently exploited vulnerabilities.

“Globally, in 2021, malicious cyber actors targeted internet-facing systems, such as email servers and virtual private network (VPN) servers, with exploits of newly disclosed vulnerabilities. For most of the top exploited vulnerabilities, researchers or other actors released proof of concept (POC) code within two weeks of the vulnerability’s disclosure, likely facilitating exploitation by a broader range of malicious actors.” reads the advisory published by CISA. “To a lesser extent, malicious cyber actors continued to exploit publicly known, dated software vulnerabilities—some of which were also routinely exploited in 2020 or earlier. The exploitation of older vulnerabilities demonstrates the continued risk to organizations that fail to patch software in a timely manner or are using software that is no longer supported by a vendor.”

Below is the list published by the government agency:

top 15 most exploited software vulnerabilitiestop 15 most exploited software vulnerabilities

The list includes CVE-2021-21972 affecting VMware vSphere Client, CVE-2021-26084 in Atlassian Confluence, CVE-2021-40539 in Zoho ManageEngine AD SelfService Plus, CVE-2018-13379 in Fortinet FortiOS and FortiProxy, CVE-2019-11510 in Pulse Secure Pulse Connect Secure CVE-2019-11510), Log4Shell, ProxyLogon ProxyShell, and ZeroLogon.

The cybersecurity agency also shared a second table containing routinely exploited by threat cyber actors in 2021. 

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Pierluigi Paganini

(SecurityAffairs – hacking, SolarMarker)

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Pierluigi Paganini

Pierluigi Paganini is member of the ENISA (European Union Agency for Network and Information Security) Threat Landscape Stakeholder Group and Cyber G7 Group, he is also a Security Evangelist, Security Analyst and Freelance Writer. Editor-in-Chief at "Cyber Defense Magazine", Pierluigi is a cyber security expert with over 20 years experience in the field, he is Certified Ethical Hacker at EC Council in London. The passion for writing and a strong belief that security is founded on sharing and awareness led Pierluigi to find the security blog "Security Affairs" recently named a Top National Security Resource for US. Pierluigi is a member of the "The Hacker News" team and he is a writer for some major publications in the field such as Cyber War Zone, ICTTF, Infosec Island, Infosec Institute, The Hacker News Magazine and for many other Security magazines. Author of the Books "The Deep Dark Web" and “Digital Virtual Currency and Bitcoin”.

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