CVE-2021-42258

CVE-2021-42258 is an unauthenticated SQL injection flaw (CWE-89) in BQE BillQuick Web Suite 2018 through 2021, fixed in version 22.0.9.1, that can be triggered through user-supplied input such as the txtID (username) parameter of the web interface. Because attacker-controlled input reaches the backend Microsoft SQL Server, an unauthenticated attacker with network access to the web suite can inject SQL and abuse xp_cmdshell to execute arbitrary code on the database server under the MSSQLSERVER$ account. This yields full unauthenticated remote code execution, and in observed intrusions it was used to deploy ransomware. Any organization running an affected BillQuick Web Suite release is affected, particularly those exposing the billing portal directly to the internet. The flaw is actively exploited in the wild (added to CISA KEV on 2021-11-03 with known ransomware use) and carries a high EPSS score of 74.4%, making urgent patching advisable.

What to do: Upgrade BillQuick Web Suite to version 22.0.9.1 or later per BQE's instructions, as required by the CISA KEV entry. Until patched, restrict internet-facing access to the Web Suite server and review logs for SQL injection attempts against the username (txtID) parameter, unexpected xp_cmdshell usage, or commands running as MSSQLSERVER$; the referenced Huntress advisory includes indicators of compromise for the October 2021 ransomware campaign.