Vulnerabilities

Kaseya Unitrends Client/Agent through 10.5,5 allows remote attackers to execute arbitrary code.

An issue was discovered in Kaseya Unitrends Backup Appliance before 10.5.5. Multiple functions in the bpserverd daemon were vulnerable to arbitrary remote code execution as root. The vulnerability was caused by untrusted input (received by the server) being passed to system calls.

An issue was discovered in the server software in Kaseya Unitrends Backup Software before 10.5.5-2. There is authenticated remote code execution.

An attacker can upload files with the privilege of the Web Server process for Kaseya VSA Unified Remote Monitoring & Management (RMM) 9.5.4.2149 and subsequently use these files to execute asp commands The api /SystemTab/uploader.aspx is vulnerable to an unauthenticated arbitrary file upload leading to RCE. An attacker can upload files with the privilege of the Web Server process and subsequently use these files to execute asp commands. Detailed description --- Given the following request: ``` POST /SystemTab/uploader.aspx?Filename=shellz.aspx&PathData=C%3A%5CKaseya%5CWebPages%5C&__RequestValidationToken=ac1906a5-d511-47e3-8500-47cc4b0ec219&qqfile=shellz.aspx HTTP/1.1 Host: 192.168.1.194 Cookie: sessionId=92812726; %5F%5FRequestValidationToken=ac1906a5%2Dd511%2D47e3%2D8500%2D47cc4b0ec219 Content-Length: 12 private const string password = "pass"; // The password ( pass ) private const string style = "dark"; // The style ( light / dark ) protected void Page_Load(object sender, EventArgs e) { //this.Remote(password); this.Login(password); this.Style(); this.ServerInfo(); ``` The attacker can control the name of the file written via the qqfile parameter and the location of the file written via the PathData parameter. Even though the call requires that a sessionId cookie is passed we have determined that the sessionId is not actually validated and any numeric value is accepted as valid. Security issues discovered --- * a sessionId cookie is required by /SystemTab/uploader.aspx, but is not actually validated, allowing an attacker to bypass authentication * /SystemTab/uploader.aspx allows an attacker to create a file with arbitrary content in any place the webserver has write access * The web server process has write access to the webroot where the attacker can execute it by requesting the URL of the newly created file. Impact --- This arbitrary file upload allows an attacker to place files of his own choosing on any location on the hard drive of the server the webserver process has access to, including (but not limited to) the webroot. If the attacker uploads files with code to the webroot (e.g. aspx code) he can then execute this code in the context of the webserver to breach either the integrity, confidentiality, or availability of the system or to steal credentials of other users. In other words, this can lead to a full system compromise.

Kaseya VSA before 9.5.7 exposes an unauthenticated client download page (/dl.asp) that leaks agent credentials: the Windows agent stores an Agent_Guid and AgentPassword in KaseyaD.ini, and supplying these to dl.asp via GET parameters authenticates the requester and returns a sessionId cookie. That sessionId can then be used to bypass authentication against services not intended for agent use, and anyone who obtains KaseyaD.ini from a managed endpoint gains enough information to penetrate the VSA installation and its managed clients. On-premises VSA deployments are affected by default, since the vulnerable download page is part of the standard installation. The flaw was exploited in the wild in July 2021 as part of the REvil ransomware campaign against Kaseya VSA, is listed in CISA's Known Exploited Vulnerabilities catalog (added 2021-11-03) with known ransomware use, and carries a very high EPSS of 85.7%.

Do: Upgrade Kaseya VSA to 9.5.7 or later per vendor instructions, as required by CISA's KEV catalog. Restrict internet access to the VSA download page (/dl.asp) or disable the agent-login capability there until patched, and review logs for dl.asp GET requests carrying agent credentials (un/pw parameters) or sessionId-based access to services not intended for agent use. Given known ransomware use, treat any unpatched, internet-exposed VSA server as high risk and check managed endpoints for exposed KaseyaD.ini credential material.

An issue was discovered in Kaseya VSA RMM through 9.5.0.22. When using the default configuration, the LAN Cache feature creates a local account FSAdminxxxxxxxxx (e.g., FSAdmin123456789) on the server that hosts the LAN Cache and all clients that are assigned to a LAN Cache. This account is placed into the local Administrators group of all clients assigned to the LAN Cache. When the assigned client is a Domain Controller, the FSAdminxxxxxxxxx account is created as a domain account and automatically added as a member of the domain BUILTIN\Administrators group. Using the well known Pass-the-Hash techniques, an attacker can use the same FSAdminxxxxxxxxx hash from any LAN Cache client and pass this to a Domain Controller, providing administrative rights to the attacker on any Domain Controller. (Local account Pass-the-Hash mitigations do not protect domain accounts.)

An issue was discovered in Kaseya Virtual System Administrator (VSA) through 9.4.0.37. It has a critical information disclosure vulnerability. An unauthenticated attacker can send properly formatted requests to the web application and download sensitive files and information. For example, the /DATAREPORTS directory can be farmed for reports. Because this directory contains the results of reports such as NMAP, Patch Status, and Active Directory domain metadata, an attacker can easily collect this critical information and parse it for information. There are a number of directories affected.

An unauthenticated SQL injection (CWE-89) exists in the ConnectWise ManagedITSync integration (through 2017) for Kaseya Virtual System Administrator (VSA), triggered through the ManagedIT.asmx page of the VSA web interface. Any unauthenticated attacker who can reach that page over the network can submit arbitrary SQL queries, both read and write, gaining full direct access to the VSA database and effectively running remote commands on the server. Because VSA servers centrally manage endpoints for managed service providers, compromise can cascade downstream: in February 2019 attackers actively exploited this flaw to download and execute ransomware payloads on all endpoints managed by affected VSA servers. Organizations are affected if they run Kaseya VSA with the ManagedITSync integration enabled and the ManagedIT.asmx page reachable by untrusted users. Exploitation is confirmed in the wild (CISA KEV, added 2022-05-24; known ransomware use), EPSS estimates an 86.8% probability of exploitation within 30 days, and CISA notes the impacted product is end-of-life.

Do: Because CISA notes the impacted product is end-of-life, disconnect or decommission any Kaseya VSA still running the ConnectWise ManagedITSync integration; otherwise update the integration beyond the 2017 version or disable it and remove public network access to the ManagedIT.asmx page of the VSA web interface. Restrict the VSA web interface to trusted networks and check managed endpoints for signs of the February 2019 ransomware exploitation.

It is possible to exploit a Time of Check & Time of Use (TOCTOU) vulnerability by winning a race condition when Kaseya Virtual System Administrator agent 9.3.0.11 and earlier tries to execute its binaries from working and/or temporary folders. Successful exploitation results in the execution of arbitrary programs with "NT AUTHORITY\SYSTEM" privileges.

It was discovered that the Unitrends Backup (UB) before 10.1.0 user interface was exposed to an authentication bypass, which then could allow an unauthenticated user to inject arbitrary commands into its /api/hosts parameters using backquotes.

It was discovered that the api/storage web interface in Unitrends Backup (UB) before 10.0.0 has an issue in which one of its input parameters was not validated. A remote attacker could use this flaw to bypass authentication and execute arbitrary commands with root privilege on the target system.