The provided information describes a malware threat identified as "Locky" ransomware variant from October 3, 2017. Locky is a well-known ransomware family that encrypts victims' files and demands ransom payments for decryption keys. This particular variant is indicated by the offline marker ".ykcol" and the use of filenames resembling "INVOICE" and archive files like "A_1234567890.7z", which suggests a distribution method involving malicious attachments mimicking invoices compressed in 7z archives. The ransomware encrypts files on infected systems, appending the ".ykcol" extension to encrypted files, effectively locking users out of their data. The threat level is noted as low in this record, with no known exploits in the wild at the time of publication, indicating limited active campaigns or reduced impact compared to other Locky variants. However, Locky ransomware historically has been distributed via phishing emails containing malicious attachments or links, exploiting user interaction to execute the malware. The lack of affected versions or patch links suggests this is a generic malware sample rather than a vulnerability in a specific product. The threat is categorized under ransomware, which primarily impacts data confidentiality and availability by encrypting files and demanding ransom payments. The technical details show a moderate threat level (3) and minimal analysis (1), reflecting limited detailed information available for this variant.

For European organizations, Locky ransomware poses a risk primarily to data availability and confidentiality. If executed, it can encrypt critical business files, leading to operational disruption, financial losses due to ransom payments or downtime, and potential reputational damage. Sectors with high reliance on digital documents, such as finance, healthcare, legal, and public administration, are particularly vulnerable. Although this variant is marked as low severity and no active exploits were reported at the time, the historical impact of Locky ransomware campaigns in Europe has been significant, with widespread infections causing costly remediation efforts. The use of invoice-themed attachments targets business users, increasing the likelihood of successful phishing attacks. European organizations must consider the risk of infection vectors such as phishing emails and ensure robust defenses against such social engineering tactics. The offline nature of this variant may limit its propagation capabilities, but infected endpoints can still suffer severe data loss without proper backups.

To mitigate the risk from Locky ransomware and similar threats, European organizations should implement targeted measures beyond generic advice: 1) Enhance email security by deploying advanced anti-phishing and attachment sandboxing solutions to detect and block malicious invoice-themed attachments, especially compressed archives like .7z files. 2) Conduct regular, focused user awareness training emphasizing the identification of phishing emails with financial or invoice-related lures. 3) Implement strict attachment handling policies, such as blocking or quarantining executable or archive files from untrusted sources. 4) Maintain comprehensive, tested offline backups of critical data to enable recovery without paying ransom. 5) Employ endpoint detection and response (EDR) tools capable of detecting ransomware behavior patterns, including file encryption activities and unusual file extension changes. 6) Enforce application whitelisting and least privilege principles to limit malware execution and lateral movement. 7) Monitor network traffic for indicators of ransomware communication or data exfiltration attempts. These specific controls address the known infection vectors and operational impacts of Locky ransomware variants.