CVE-2021-30116
Kaseya Virtual System/Server Administrator (VSA) Information Disclosure
- Published9 Jul 2021
- Added to CISA KEV3 Nov 2021
- Remediation due17 Nov 2021
Description
Kaseya VSA before 9.5.7 allows credential disclosure, as exploited in the wild in July 2021. By default Kaseya VSA on premise offers a download page where the clients for the installation can be downloaded. The default URL for this page is https://x.x.x.x/dl.asp When an attacker download a client for Windows and installs it, the file KaseyaD.ini is generated (C:\Program Files (x86)\Kaseya\XXXXXXXXXX\KaseyaD.ini) which contains an Agent_Guid and AgentPassword This Agent_Guid and AgentPassword can be used to log in on dl.asp (https://x.x.x.x/dl.asp?un=840997037507813&pw=113cc622839a4077a84837485ced6b93e440bf66d44057713cb2f95e503a06d9) This request authenticates the client and returns a sessionId cookie that can be used in subsequent attacks to bypass authentication. Security issues discovered --- * Unauthenticated download page leaks credentials * Credentials of agent software can be used to obtain a sessionId (cookie) that can be used for services not intended for use by agents * dl.asp accepts credentials via a GET request * Access to KaseyaD.ini gives an attacker access to sufficient information to penetrate the Kaseya installation and its clients. Impact --- Via the page /dl.asp enough information can be obtained to give an attacker a sessionId that can be used to execute further (semi-authenticated) attacks against the system.
CVSS 3.1 breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:HAffected products
Remediation
References
- https://csirt.divd.nl/2021/07/04/Kaseya-Case-Update-2/
- https://csirt.divd.nl/2021/07/07/Kaseya-Limited-Disclosure/
- https://helpdesk.kaseya.com/hc/en-gb/articles/4403440684689-Important-Notice-July-2nd-2021
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-30116
- https://www.secpod.com/blog/kaseya-vsa-zero-day-by-revil/
Related CVEs
Recent high-severity vulnerabilities sharing a weakness type.
Frequently asked
Is CVE-2021-30116 being actively exploited?
Yes. CVE-2021-30116 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 3 Nov 2021. It has been used in ransomware campaigns.
How severe is CVE-2021-30116?
CVE-2021-30116 has a CVSS 3.1 base score of 10.0, rated critical. EPSS estimates a 85.7% probability of exploitation.
Which products are affected by CVE-2021-30116?
Affected products include Kaseya Vsa Agent, Kaseya Vsa Server.
How do I fix CVE-2021-30116?
Upgrade affected software to a fixed version, for example Kaseya Vsa Agent 9.5.0.24, Kaseya Vsa Server 9.5.7a or later, then confirm no affected versions remain in your inventory.
How Secuno handles this
Secuno correlates vulnerabilities like CVE-2021-30116 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. Because it is on the CISA KEV list, Secuno flags any affected asset as top-priority automatically. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.
Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.