Actively exploited · Published Jul 9, 2021 · Assigned by mitre
CVE-2021-30116Unauthenticated credential leak and business logic flaw in Kaseya VSA <= v9.5.6
Critical 10.0 Exploited Ransomware
In plain English
A critical-severity security flaw in Virtual System/Server Administrator (VSA) from Kaseya. Attackers are actively exploiting it in the wild (listed by CISA on November 3, 2021). It has been used in ransomware campaigns. The chance it is exploited in the next 30 days is estimated at 85.7% (higher than 99.7% of all known vulnerabilities). Ready-made attack tooling exists: Nuclei. Apply updates per vendor instructions.
CISA guidance
Apply updates per vendor instructions.
Federal agencies must remediate by Nov 17, 2021.
Official 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.
Affected products (as reported)
Weakness: CWE-522 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
References
- https://csirt.divd.nl/2021/07/04/Kaseya-Case-Update-2/
- https://helpdesk.kaseya.com/hc/en-gb/articles/4403440684689-Important-Notice-July-2nd-2021
- https://csirt.divd.nl/2021/07/07/Kaseya-Limited-Disclosure/
- https://www.secpod.com/blog/kaseya-vsa-zero-day-by-revil/
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-30116 government-resource