#StopRansomware: Gunra Ransomware

Advisory at a Glance Title #StopRansomware: Gunra Ransomware Original Publication August 10, 2026 Executive Summary Gunra is a ransomware-as-a-service (RaaS) used by affiliates to target government, critical infrastructure, and other organizations. The Gunra ransomware variant first appeared in 2025 and expanded to RaaS operations in 2026. The actors leverage a double-extortion model, both encrypting data…

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Russian State-Supported Cyber Actors Conduct Phishing Campaign Targeting Users of Zimbra Collaboration Suite

Russian State-Supported Cyber Actors Conduct Phishing Campaign Targeting Users of Zimbra Collaboration Suite Executive summary  A group of Russian state-supported cyber actors has been targeting and compromising various Western government and commercial organizations using the Zimbra Collaboration Suite (ZCS) software since at least July 2025. The Russian state-supported advanced persistent threat (APT) group’s activity is…

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Improve Router Hygiene to Protect Against Russian State-Sponsored Targeting

Russian Government-Sponsored Activity Targets Poorly Configured and Vulnerable Devices Across Critical Sectors Executive summary Russian Federal Security Service (FSB) Center 16 cyber actors continue to exploit poorly configured and vulnerable networking devices worldwide, opportunistically compromising multiple critical infrastructure sector networks. This joint Cybersecurity Advisory (CSA) builds on FBI’s Russian Government Cyber Actors Targeting Networking Devices,…

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Defending Against China-Nexus Covert Networks of Compromised Devices

Defending against china-nexus covert networks of compromised devices executive summary Defending against China-nexus covert networks of compromised devices  Explaining the widespread shift in tactics, techniques and procedures (TTPs) towards networks of compromised infrastructure, and how to defend against it  Summary With support from the UK Cyber League, this advisory has been jointly released by the…

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Iranian-Affiliated Cyber Actors Exploit Programmable Logic Controllers Across US Critical Infrastructure

Advisory at a Glance Title Iranian-Affiliated Cyber Actors Exploit Programmable Logic Controllers Across US Critical Infrastructure Original Publication April 7, 2026 Executive Summary Iran-affiliated advanced persistent threat (APT) actors are conducting exploitation activity targeting internet-facing operational technology (OT) devices, including programmable logic controllers (PLCs) manufactured by Rockwell Automation/Allen-Bradley. This activity has led to PLC disruptions…

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Pro-Russia Hacktivists Conduct Opportunistic Attacks Against US and Global Critical Infrastructure

Summary Note: This joint Cybersecurity Advisory is being published as an addition to the Cybersecurity and Infrastructure Security Agency (CISA) May 6, 2025, joint fact sheet Primary Mitigations to Reduce Cyber Threats to Operational Technology and European Cybercrime Centre’s (EC3) Operation Eastwood, in which CISA, Federal Bureau of Investigation (FBI), Department of Energy (DOE), Environmental…

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CISA Shares Lessons Learned from an Incident Response Engagement

Advisory at a Glance Executive Summary CISA began incident response efforts at a U.S. federal civilian executive branch (FCEB) agency following the detection of potential malicious activity identified through security alerts generated by the agency’s endpoint detection and response (EDR) tool. CISA identified three lessons learned from the engagement that illuminate how to effectively mitigate…

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Countering Chinese State-Sponsored Actors Compromise of Networks Worldwide to Feed Global Espionage System

Executive summary People’s Republic of China (PRC) state-sponsored cyber threat actors are targeting networks globally, including, but not limited to, telecommunications, government, transportation, lodging, and military infrastructure networks. While these actors focus on large backbone routers of major telecommunications providers, as well as provider edge (PE) and customer edge (CE) routers, they also leverage compromised…

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CISA and USCG Identify Areas for Cyber Hygiene Improvement After Conducting Proactive Threat Hunt at US Critical Infrastructure Organization

Summary The Cybersecurity and Infrastructure Security Agency (CISA) and U.S. Coast Guard (USCG) are issuing this Cybersecurity Advisory to present findings from a recent CISA and USCG hunt engagement. The purpose of this advisory is to highlight identified cybersecurity issues, thereby informing security defenders in other organizations of potential similar issues and encouraging them to…

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#StopRansomware: Interlock

Summary Note: This joint Cybersecurity Advisory is part of an ongoing #StopRansomware effort to publish advisories for network defenders that detail various ransomware variants and ransomware threat actors. These #StopRansomware advisories include recently and historically observed tactics, techniques, and procedures (TTPs) and indicators of compromise (IOCs) to help organizations protect against ransomware. Visit stopransomware.gov to…

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