{ "id": "db591c00-d505-45db-98c3-940c6a910493", "created_at": "2026-04-06T03:37:33.520764Z", "updated_at": "2026-04-10T03:20:42.255261Z", "deleted_at": null, "sha1_hash": "d7f7be37e78739a0917fa799bc7885425d3300e4", "title": "TFlower Ransomware Campaign - Canadian Centre for Cyber Security", "llm_title": "", "authors": "", "file_creation_date": "0001-01-01T00:00:00Z", "file_modification_date": "0001-01-01T00:00:00Z", "file_size": 40970, "plain_text": "TFlower Ransomware Campaign - Canadian Centre for Cyber\r\nSecurity\r\nArchived: 2026-04-06 02:50:36 UTC\r\nNumber: AL19-201\r\nDate: 20 September 2019\r\nPurpose\r\nOn 30 July 2019 a new variant of ransomware A type of malware that denies a user's access to a system or data\r\nuntil a sum of money is paid. named TFlower was discovered. The Cyber Centre has become aware of this\r\nransomware recently affecting the Canadian public.\r\nAssessment\r\nThe initial infection vector for this malware Malicious software designed to infiltrate or damage a computer\r\nsystem, without the owner's consent. Common forms of malware include computer viruses, worms, Trojans,\r\nspyware, and adware. appears to be through Remote Desktop services, and other infection vectors may include\r\nemail spam and malicious attachments, deceptive downloads, botnets, malicious ads, web injects, fake updates\r\nand repackaged and infected installers. Once a malicious actor infects a system, they may attempt to move\r\nlaterally across the network through tools such as PowerShell Empire, PSExec, etc.\r\nThe malware will initially contact a Command and Control(C2) server to indicate its readiness to encrypt the\r\ncontents on the target system. It will then delete shadow copies and disable recovery features in Windows 10 and\r\ncreate persistence by adding a key in the logged in user's software registry hive. It will encrypt files and mark\r\nthem by inserting the string \"*tflower\" at the beginning of the file but will not change the filename.\r\nFinally the malware will update the C2 server and leave a ransom note named “!_Notice_!.txt” placed throughout\r\nthe computer and on the Windows Desktop.\r\nThe Cyber Centre recommends that all system owners apply the latest security patches immediately, and that\r\nsystem users are reminded to be vigilant when following unsolicited links and opening unexpected document\r\nattachments in emails, even if they come from known contacts.\r\nSuggested action\r\nInstall the latest updates for the vulnerable operating systems.\r\nDisable Remote Desktop Services if not required. If required, closely monitor network traffic and the logs\r\nof any vulnerable systems for suspicious activity.\r\nEnable Network Level Authentication (NLA) on all currently supported versions of Windows. This is a\r\npartial mitigation which will prevent the spread of the malware. With NLA enabled, an actor would first\r\nhttps://cyber.gc.ca/en/alerts/tflower-ransomware-campaign\r\nPage 1 of 2\n\nneed to have credentials to an account on the target system.\r\nBlock TCP port 3389 on the firewall, if possible. This will prevent unauthorized access from the Internet.\r\nNever open attachments from unknown or unverified sources.\r\nWhitelist applications to prevent unauthorized applications from running.\r\nUse antivirus and ensure that it is diligently kept up to date.\r\nMinimize the number of users with administrative privileges and ensure users do not have privileges to\r\ninstall software on their devices without the authorization of an administrator.\r\nDisable macros for documents received via email.\r\nFollow the Government of Canada’s guidance to stay CyberSafe https://www.getcybersafe.gc.ca/index-en.aspx\r\nReferences\r\nCCCS Alert on Critical Remote Desktop Vulnerability A flaw or weakness in the design or implementation of an\r\ninformation system or its environment that could be exploited to adversely affect an organization's assets or\r\noperations. : https://cyber.gc.ca/en/alerts/critical-microsoft-remote-desktop-vulnerability\r\nNote to readers\r\nThe Canadian Centre for Cyber Security The protection of digital information, as well as the integrity of the\r\ninfrastructure housing and transmitting digital information. More specifically, cyber security includes the body of\r\ntechnologies, processes, practices and response and mitigation measures designed to protect networks, computers,\r\nprograms and data from attack, damage or unauthorized access so as to ensure confidentiality, integrity and\r\navailability. (Cyber Centre) operates as part of the Communications Security Establishment. We are Canada's\r\nnational authority on cyber security and we lead the government's response to cyber security events. As Canada's\r\nnational computer security incident response team, the Cyber Centre works in close collaboration with\r\ngovernment departments, critical infrastructure Processes, systems, facilities, technologies, networks, assets, and\r\nservices essential to the health, safety, security, or economic well-being of Canadians and the effective functioning\r\nof government. Critical infrastructure can be stand-alone or interconnected and interdependent within and across\r\nprovinces, territories, and national borders. Disruptions of critical infrastructure could result in catastrophic loss of\r\nlife, adverse economic effects, and significant harm to public confidence. , Canadian businesses and international\r\npartners to prepare for, respond to, mitigate, and recover from cyber events. We do this by providing authoritative\r\nadvice and support, and coordinating information sharing and incident response. The Cyber Centre is outward-facing, welcoming partnerships that help build a stronger, more resilient cyber space in Canada.\r\nSource: https://cyber.gc.ca/en/alerts/tflower-ransomware-campaign\r\nhttps://cyber.gc.ca/en/alerts/tflower-ransomware-campaign\r\nPage 2 of 2", "extraction_quality": 1, "language": "EN", "sources": [ "Malpedia", "ETDA" ], "references": [ "https://cyber.gc.ca/en/alerts/tflower-ransomware-campaign" ], "report_names": [ "tflower-ransomware-campaign" ], "threat_actors": [ { "id": "d90307b6-14a9-4d0b-9156-89e453d6eb13", "created_at": "2022-10-25T16:07:23.773944Z", "updated_at": "2026-04-10T02:00:04.746188Z", "deleted_at": null, "main_name": "Lead", "aliases": [ "Casper", "TG-3279" ], "source_name": "ETDA:Lead", "tools": [ "Agentemis", "BleDoor", "Cobalt Strike", "CobaltStrike", "RbDoor", "RibDoor", "Winnti", "cobeacon" ], "source_id": "ETDA", "reports": null } ], "ts_created_at": 1775446653, "ts_updated_at": 1775791242, "ts_creation_date": 0, "ts_modification_date": 0, "files": { "pdf": "https://archive.orkl.eu/d7f7be37e78739a0917fa799bc7885425d3300e4.pdf", "text": "https://archive.orkl.eu/d7f7be37e78739a0917fa799bc7885425d3300e4.txt", "img": "https://archive.orkl.eu/d7f7be37e78739a0917fa799bc7885425d3300e4.jpg" } }