CVE-2018-20753
Kaseya VSA Remote Code Execution Vulnerability
Kaseya Virtual System/Server Administrator (VSA)
Kaseya VSA RMM before R9.3 9.3.0.35, R9.4 before 9.4.0.36, and R9.5 before 9.5.0.5 allows unprivileged remote attackers to execute PowerShell payloads on all managed devices. In January 2018, attackers actively exploited this vulnerability in the wild.
Exploitation status
CISA Known Exploited Vulnerabilities
Listed by CISA on 13 April 2022. US federal agencies were required to remediate it by 4 May 2022. CISA records this vulnerability as known to be used in ransomware campaigns.
EPSS — exploitation probability
FIRST puts the probability of exploitation activity in the next 30 days at 29.6%, which is higher than 98.2% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Frequently asked questions
Is CVE-2018-20753 being exploited by ransomware groups?
No ransomware group in this database is currently recorded as exploiting CVE-2018-20753.
What does CVE-2018-20753 affect?
CVE-2018-20753 affects Kaseya Virtual System/Server Administrator (VSA). Kaseya VSA RMM before R9.3 9.3.0.35, R9.4 before 9.4.0.36, and R9.5 before 9.5.0.5 allows unprivileged remote attackers to execute PowerShell payloads on all managed devices. In January 2018, attackers actively exploited this vulnerability in the wild.
How severe is CVE-2018-20753?
CVE-2018-20753 is rated CRITICAL with a CVSS base score of 9.8. EPSS puts the probability of exploitation in the next 30 days at 29.6%, higher than 98.2% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 4 May 2022.
How should organisations respond to CVE-2018-20753?
Apply the vendor patch for Kaseya Virtual System/Server Administrator (VSA) as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.