Rogue ScreenConnect Installations Across Unrelated Hosts Suggest Worm-Like Activity
Huntress observed rogue ScreenConnect deployments with worm-like VBScript propagation across unrelated organizations, prompting a ConnectWise advisory on file transfer behavior.
Huntress identified multiple incidents in late August 2026 where social engineering led to rogue ScreenConnect remote access clients deployed on victim machines, which then spawned wscript.exe to run four VBScript payloads (1.vbs through 4.vbs) for profiling, telemetry collection, and persistence via a WindowsServiceHost Run key. Modified ScreenConnect clients propagated the VBScript chain to connected endpoints, creating worm-like spread. ConnectWise published an advisory on September 3, 2026, confirming an issue affecting file transfer behavior in both cloud and on-premises ScreenConnect deployments, with a CVE and fix expected within the week; partners were advised to review and disable TransferFiles permissions in the interim.
2026-004: Critical Vulnerability in SharePoint Exploited
CVE-2026-20963 (CVSS 9.8), an unauthenticated RCE in on-prem SharePoint, was added to CISA's KEV on 18 March 2026 and is actively exploited.
CERT-EU warns about CVE-2026-20963, a CVSS 9.8 unauthenticated remote code execution flaw in SharePoint caused by deserialisation of untrusted data, affecting SharePoint Server Subscription Edition, 2019, and Enterprise Server 2016. Microsoft raised the CVSS score on 17 March 2026 and the flaw entered CISA's Known Exploited Vulnerabilities catalogue on 18 March 2026. Three additional SharePoint RCE flaws (CVE-2026-26106, CVE-2026-26113, CVE-2026-26114) were fixed in the March 2026 release. CERT-EU urges immediate patching of internet-facing servers plus AMSI Full Mode, EDR deployment, ASP.NET machine key rotation, and compromise assessments.