CVE-2021-30116 - Unauthenticated credential leak and business logic flaw in Kaseya VSA <= v9.5.6
|CVSS||Base score: 10|
|Solution||Upgrade to a version after 9.5.6|
|Last modified||20 Jun 2022 07:35|
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.
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.
Image 1. Screenshot of dl.sap
Image 2. Screenshot of KaseyaD.ini file
Image 3. Screenshot of obtaining a session cookie