Actively exploited in the wild
Kaseya Virtual System/Server Administrator (VSA) Information Disclosure Vulnerability
Kaseya - Virtual System/Server Administrator (VSA) · Listed in the CISA KEV since 2021-11-03. This indicates confirmed attacks in production environments.
Required action: Apply updates per vendor instructions.
CVE-2021-30116
CriticalCVSS 10.0KEVExploitation Probability (EPSS)
Very high risk100th percentile - higher than 100% of all known CVEs
Summary
Kaseya VSA before 9.5.7 allows credential disclosure. The default download page (dl.asp) is unauthenticated and generates KaseyaD.ini with Agent_Guid and AgentPassword, which can be used to obtain a sessionId and bypass authentication.
Risk Assessment
An attacker can gain access to the Kaseya installation and its clients, potentially leading to full compromise of managed systems.
Recommendation
Upgrade Kaseya VSA to 9.5.7 or later. Restrict access to dl.asp and protect configuration files from unauthorized reading.
Original NVD description (English source)
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.