Threat Actors Exploiting Citrix CVE-2023-3519 to Implant Webshells

SUMMARY The Cybersecurity and Infrastructure Security Agency (CISA) is releasing this Cybersecurity Advisory to warn network defenders about exploitation of CVE-2023-3519, an unauthenticated remote code execution (RCE) vulnerability affecting NetScaler (formerly Citrix) Application Delivery Controller (ADC) and NetScaler Gateway. In June 2023, threat actors exploited this vulnerability as a zero-day to drop a webshell on…

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Enhanced Monitoring to Detect APT Activity Targeting Outlook Online

SUMMARY In June 2023, a Federal Civilian Executive Branch (FCEB) agency identified suspicious activity in their Microsoft 365 (M365) cloud environment. The agency reported the activity to Microsoft and the Cybersecurity and Infrastructure Security Agency (CISA), and Microsoft determined that advanced persistent threat (APT) actors accessed and exfiltrated unclassified Exchange Online Outlook data. CISA and…

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Increased Truebot Activity Infects U.S. and Canada Based Networks

SUMMARY The Cybersecurity and Infrastructure Security Agency (CISA), the Federal Bureau of Investigation (FBI), the Multi-State Information Sharing and Analysis Center (MS-ISAC), and the Canadian Centre for Cyber Security (CCCS) are releasing this joint Cybersecurity Advisory (CSA) in response to cyber threat actors leveraging newly identified Truebot malware variants against organizations in the United States…

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Understanding Ransomware Threat Actors: LockBit

SUMMARY In 2022, LockBit was the most deployed ransomware variant across the world and continues to be prolific in 2023. Since January 2020, affiliates using LockBit have attacked organizations of varying sizes across an array of critical infrastructure sectors, including financial services, food and agriculture, education, energy, government and emergency services, healthcare, manufacturing, and transportation….

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#StopRansomware: CL0P Ransomware Gang Exploits CVE-2023-34362 MOVEit Vulnerability

SUMMARY Note: this joint Cybersecurity Advisory (CSA) 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…

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People's Republic of China State-Sponsored Cyber Actor Living off the Land to Evade Detection

Summary The United States and international cybersecurity authorities are issuing this joint Cybersecurity Advisory (CSA) to highlight a recently discovered cluster of activity of interest associated with a People’s Republic of China (PRC) state-sponsored cyber actor, also known as Volt Typhoon. Private sector partners have identified that this activity affects networks across U.S. critical infrastructure…

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#StopRansomware: BianLian Ransomware Group

Summary Note: This joint Cybersecurity Advisory (CSA) 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…

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Malicious Actors Exploit CVE-2023-27350 in PaperCut MF and NG

SUMMARY The Federal Bureau of Investigation (FBI) and Cybersecurity and Infrastructure Security Agency (CISA) are releasing this joint Cybersecurity Advisory (CSA) in response to the active exploitation of CVE-2023-27350. This vulnerability occurs in certain versions of PaperCut NG and PaperCut MF and enables an unauthenticated actor to execute malicious code remotely without credentials. PaperCut released…

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Hunting Russian Intelligence “Snake” Malware

SUMMARY The Snake implant is considered the most sophisticated cyber espionage tool designed and used by Center 16 of Russia’s Federal Security Service (FSB) for long-term intelligence collection on sensitive targets. To conduct operations using this tool, the FSB created a covert peer-to-peer (P2P) network of numerous Snake-infected computers worldwide. Many systems in this P2P…

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APT28 Exploits Known Vulnerability to Carry Out Reconnaissance and Deploy Malware on Cisco Routers

APT28 accesses poorly maintained Cisco routers and deploys malware on unpatched devices using CVE-2017-6742. Overview and Context The UK National Cyber Security Centre (NCSC), the US National Security Agency (NSA), US Cybersecurity and Infrastructure Security Agency (CISA) and US Federal Bureau of Investigation (FBI) are releasing this joint advisory to provide details of tactics, techniques…

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