The Locky ransomware first emerged in early 2016 as a significant malware threat distributed primarily via malspam campaigns. This particular instance, dated April 28, 2016, involves Locky being delivered through malicious spam emails (malspam) that typically contain infected attachments or links. Once executed, Locky encrypts a wide range of file types on the victim's system, rendering them inaccessible without the decryption key held by the attackers. The ransomware then demands a ransom payment, usually in cryptocurrency, in exchange for the decryption key. Locky is notable for its use of strong encryption algorithms, making recovery without the key extremely difficult. The malware often spreads through phishing emails that trick users into opening malicious attachments, such as Word documents with macros or JavaScript files. Although this specific report does not list affected versions or known exploits in the wild, Locky’s distribution method relies heavily on social engineering rather than exploiting software vulnerabilities. The threat level indicated is moderate (3 out of a higher scale), and the severity is labeled as low in this report, likely reflecting the time of publication and the availability of mitigation strategies. However, Locky’s impact historically has been considerable due to its ability to disrupt business operations by encrypting critical data.

For European organizations, Locky ransomware poses a significant risk primarily through operational disruption and potential financial loss. The encryption of critical business data can halt operations, leading to downtime and loss of productivity. Additionally, the ransom payments, if made, can result in direct financial losses. Beyond immediate operational impacts, organizations may face reputational damage and potential regulatory consequences, especially under the GDPR framework, if personal data is affected or if the incident is not properly reported. The threat is particularly concerning for sectors with high data sensitivity and operational continuity requirements, such as healthcare, finance, and public services. Although Locky does not exploit software vulnerabilities directly, its reliance on phishing means that organizations with less mature email security and user awareness programs are more vulnerable. The low severity rating in this report may underestimate the broader impact seen historically, especially if organizations fail to implement robust preventive measures.

To effectively mitigate the Locky ransomware threat, European organizations should implement a multi-layered defense strategy beyond generic advice. First, enhance email security by deploying advanced spam filtering and attachment sandboxing to detect and block malicious emails before reaching end users. Implement strict macro policies in Office applications, disabling macros by default and only enabling them for trusted documents. Conduct regular, targeted user awareness training focused on phishing recognition and safe handling of email attachments. Maintain comprehensive, tested backups of critical data with offline or immutable storage to ensure recovery without paying ransom. Employ endpoint detection and response (EDR) solutions capable of identifying ransomware behaviors such as rapid file encryption and unusual file modifications. Network segmentation can limit ransomware spread within an organization. Finally, establish and regularly test incident response plans specific to ransomware scenarios to ensure rapid containment and recovery.