N-able ships second N-central hotfix as attackers keep exploiting CVE-2026-18577
N-able shipped a second N-central hotfix as attackers actively exploit authentication bypass CVE-2026-18577, attributed to ransomware group Storm-1175.
N-able released Hotfix 2 (N-central 2026.3.1.10) to counter ongoing exploitation of CVE-2026-18577, an authentication bypass that evades the patch for the earlier CVE-2026-18556; exploitation was first detected on August 1, 2026. Post-exploitation includes using the Take Control feature to reach managed endpoints, registering a Cloudflare tunnel service for persistence, creating a 'veeam' domain account, resetting admin passwords, and disabling Microsoft and Sophos security tooling. Microsoft analysts link the activity to Storm-1175, which now deploys a new StormEncryptor ransomware strain instead of Medusa, often reaching data exfiltration and ransomware within days. Sophos and Huntress expanded the IOCs and warned that partners who patched late should treat environments as potentially compromised.
Attackers use rogue ScreenConnect clients to spread malware
Attackers deploy rogue ScreenConnect clients that spread VBScript malware to newly connected machines while ConnectWise patches a file-transfer flaw.
ConnectWise confirmed a file transfer flaw in ScreenConnect affecting both Cloud and On-Premise deployments, with a CVE identifier and official fix promised within the week; administrators can mitigate immediately by disabling TransferFiles (or TransferFilesInSession) in each role. Huntress documented incidents where social engineering installs rogue ScreenConnect clients that spawn Windows Script Host processes running four VBScript files (1.vbs-4.vbs), add a WindowsServiceHost registry Run key, and propagate to newly connected endpoints. Payloads enabled host profiling, persistence, additional ScreenConnect installs, tunneling, security-control changes, and cryptocurrency mining. ConnectWise has not confirmed a technical link between the flaw and this campaign.
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.