Hackers Exploit Marimo RCE to Steal AWS Credentials and Reach Bastion Host in 8 Seconds
Attackers exploited pre-auth RCE CVE-2026-39987 in Marimo notebooks to steal AWS credentials and SSH into a bastion host in eight seconds.
Sysdig Threat Research Team documented an intrusion abusing CVE-2026-39987, an unauthenticated RCE in Marimo's terminal WebSocket endpoint affecting versions up to 0.20.4 and fixed in 0.23.0. The attacker harvested AWS credentials from the host environment and Redis backend, queried AWS Secrets Manager to retrieve an SSH private key, and authenticated to an internet-facing SSH bastion host just eight seconds after opening the WebSocket session. Human-operated custom tooling, not an AI agent, executed the full exploit-to-lateral-movement chain.
CISA Warns Water Utilities: Find Your Exposed PLCs Before Attackers Do
CISA urged water utilities to secure internet-exposed PLCs after July 2026 attacks compromised over 100 US water and wastewater systems, suspected Iran-linked.
CISA's exposure-reduction guidance, published August 21, follows July 2026 attacks in which threat actors remotely accessed PLCs connected directly through cellular modems, changed device IP addresses and passwords, and in some cases disabled alarms and shutdown processes without notifying operators. Iran is the suspected actor, though officials stopped short of formal attribution. CISA recommends routing remote access through centrally managed secure gateways, phishing-resistant MFA, unique credentials, and external scanning of industrial protocols such as Modbus, EtherNet/IP, DNP3, BACnet and OPC UA.
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.