Security readout for executives and security teams
Plain-English summary
Kaseya VSA versions before 9.5.7 could let an attacker with a valid password skip two-factor authentication. This turns stolen credentials into full account access despite MFA being configured, which is especially serious for managed service provider environments where VSA can administer many customer systems.
Executive priority
Treat this as urgent for any still-running affected VSA system. MFA bypass on an administrative platform can convert credential theft into broad operational compromise, especially for service providers managing customer environments.
Technical view
The flaw is a server-side enforcement failure: MFA requirement state was enforced client-side. After password authentication, client-controlled MFARequired/MFAEnroled values could determine whether the second factor appeared, allowing MFA bypass for a credentialed network attacker. CVSS 3.1 is 9.9 with low complexity and high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is limited to organizations running Kaseya VSA before 9.5.7. Risk is highest where VSA login portals are reachable from the internet, privileged accounts use reusable passwords, or MSP workflows give VSA broad downstream administrative control.
Exploitation context
The source bundle does not show CISA KEV listing or cited confirmation of active exploitation for this specific CVE. Exploitation requires valid user credentials, but once those are obtained, MFA may not provide the expected barrier on affected versions.
Researcher notes
Evidence is strongest for affected version range and root cause from the CVE description. The bundle’s structured affected-product fields are sparse, so do not infer additional products. No exploit code, KEV status, or confirmed in-the-wild exploitation is provided in the supplied sources.
Mitigation direction
- Upgrade Kaseya VSA to 9.5.7 or later following vendor guidance.
- Restrict VSA administrative access to trusted networks or VPN paths.
- Reset credentials for VSA accounts if password compromise is suspected.
- Review Kaseya and DIVD advisories for any additional required actions.
- Prioritize privileged and MSP tenant administrator accounts first.
Validation and detection
- Inventory all Kaseya VSA instances and record exact versions.
- Confirm no production instance is running earlier than 9.5.7.
- Review authentication logs for MFA-enabled accounts with password-only successful logins.
- Verify MFA enforcement is server-side after remediation.
- Check whether exposed VSA portals are reachable from untrusted networks.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
Credential and access behavior lookup
The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-30120 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.9 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H3.16Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
9.9CriticalVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://csirt.divd.nl/2021/07/07/Kaseya-Limited-Disclosure/CVE reference · x_refsource_CONFIRM
- https://csrit.divd.nl/DIVD-2021-00011CVE reference · x_refsource_CONFIRM
- https://csrit.divd.nl/CVE-2021-30120CVE reference · x_refsource_CONFIRM
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.