THREATPORT/VULNERABILITY/CVE-2021-30120
CRITICAL SEVERITY

CVE-2021-30120

Vsa vulnerability

CVSS
9.9
EPSS
5.7%
EPSS pct
92th
Exploited
No known
Kaseya VSA before 9.5.7 allows attackers to bypass the 2FA requirement. The need to use 2FA for authentication in enforce client-side instead of server-side and can be bypassed using a local proxy. Thus rendering 2FA useless. Detailed description --- During the login process, after the user authenticates with username and password, the server sends a response to the client with the booleans MFARequired and MFAEnroled. If the attacker has obtained a password of a user and used an intercepting proxy (e.g. Burp Suite) to change the value of MFARequered from True to False, there is no prompt for the second factor, but the user is still logged in.
Affected vendor
Kaseya
Affected product
Vsa
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Weakness type (CWE)
  • CWE-669 — Incorrect Resource Transfer Between Spheres
Published
2021-07-09

Risk analysis

Based on its CVSS vector, this vulnerability is exploitable over the network, low attack complexity, requiring low privileges, no user interaction. Successful exploitation leads to high impact to confidentiality, high impact to integrity, high impact to availability.

Its EPSS score of 5.7% reflects a lower probability of exploitation activity in the wild over the next 30 days, placing it above 92% of all scored CVEs.

Check your external exposure to CVE-2021-30120

  • Confirm whether Kaseya Vsa is running on any internet-facing host or subdomain.
  • Match discovered service fingerprints against the version affected by CVE-2021-30120.
  • Prioritise remediation if the asset is public, business-critical, or near authentication/payment flows.

How ThreatPort helps with CVE-2021-30120

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