Threats / Kaseya / CVE-2018-20753
CVE-2018-20753
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
Kaseya Virtual System/Server Administrator (VSA) vulnerability
Kaseya VSA allows unprivileged remote attackers to execute arbitrary PowerShell commands on all managed devices, enabling widespread compromise of customer infrastructure.
Verdict
Today item, not a backlog item.
A remote code execution vulnerability in Kaseya VSA permits unauthenticated or low-privilege attackers to deploy malicious PowerShell payloads across managed endpoints without authentication, facilitating ransomware distribution and lateral movement at scale.
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
2 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-04-13), flagged for known ransomware use.
Probability (EPSS)
EPSS 0.29551 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Kaseya, Virtual System/Server Administrator (VSA). Confirm exact fixed builds in the vendor advisory.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I identify Kaseya VSA as an internet-exposed remote management platform used by managed service providers.
Business
The organization relies on VSA to manage thousands of customer endpoints across multiple industries.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I send a crafted request to VSA that bypasses authentication controls and executes arbitrary PowerShell code.
Business
The vulnerability allows a single attacker interaction to compromise all connected managed devices simultaneously.
3
Lateral reach — past segmentation narrative 3
Attacker
I deploy ransomware payloads via PowerShell execution across the entire managed device fleet.
Business
Customers experience coordinated encryption of critical systems, with ransom demands affecting business continuity across multiple organizations.
4
Data at risk — exfiltration narrative 4
Attacker
I maintain persistence and exfiltrate sensitive data from compromised endpoints before encryption.
Business
The organization faces regulatory penalties, customer liability claims, and reputational damage from the supply-chain attack vector.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05