The provided information relates to a malware threat identified as "Locky" ransomware, specifically a variant or instance noted on 2017-09-20. Locky ransomware is a well-known family of malicious software that encrypts victims' files and demands ransom payments for decryption keys. The reference to ".ykcol" and the naming pattern "Status of invoice A2171234-56" and "A2171234-56.rar" suggests that this ransomware variant disguises its payload or ransom notes using invoice-like file names, potentially to deceive users into opening malicious attachments. The malware is categorized under ransomware, which typically encrypts user data and demands payment, often in cryptocurrency, to restore access. The threat level is indicated as 3 (on an unspecified scale), with a low severity rating assigned by the source. No specific affected software versions or patches are listed, and there are no known exploits in the wild beyond the malware itself. The lack of detailed technical indicators or CWE references limits the granularity of analysis, but the presence of ransomware implies a direct threat to data confidentiality and availability through encryption and potential data loss if ransom is not paid or backups are unavailable.

For European organizations, the Locky ransomware poses a risk primarily to data availability and confidentiality. If executed successfully, it can encrypt critical business files, leading to operational disruption, financial loss due to ransom payments or downtime, and potential reputational damage. Sectors that frequently handle invoices and financial documents, such as finance, healthcare, manufacturing, and public administration, may be particularly targeted or affected due to the malware's use of invoice-themed file names to lure victims. The impact is exacerbated in organizations lacking robust backup strategies or incident response capabilities. Additionally, regulatory frameworks like GDPR impose strict data protection requirements; ransomware incidents can lead to compliance violations and fines if personal data is compromised or unavailable. Although the severity is rated low in this report, the historical impact of Locky variants has been significant, and European organizations remain attractive targets due to their economic importance and regulatory environment.

To mitigate the risk posed by Locky ransomware, European organizations should implement targeted measures beyond generic advice: 1) Enhance email filtering and attachment scanning to detect and quarantine suspicious files, especially those mimicking invoices or using uncommon extensions like ".ykcol". 2) Conduct user awareness training focused on recognizing phishing attempts and suspicious attachments, emphasizing the risks of opening unexpected invoice files. 3) Maintain and regularly test offline, immutable backups to ensure rapid recovery without paying ransom. 4) Employ endpoint detection and response (EDR) solutions capable of identifying ransomware behaviors such as rapid file encryption and unusual file renaming patterns. 5) Implement application whitelisting to restrict execution of unauthorized binaries, particularly from email attachments or temporary directories. 6) Keep all systems and security tools updated to reduce attack surface, even though no specific patches are noted for this variant. 7) Develop and rehearse incident response plans specific to ransomware scenarios to minimize downtime and data loss.