This threat involves malspam campaigns distributing the Locky ransomware, a well-known family of ransomware that encrypts victims' files and demands ransom payments for decryption keys. The campaign uses social engineering techniques involving HoeflerText notifications, which are browser notifications that can be triggered in Chrome and Firefox browsers. The attackers attempt to exploit the trust users place in browser notifications to deliver malicious payloads or lure users into executing ransomware. Locky ransomware typically spreads via malicious email attachments or links, and once executed, it encrypts a wide range of file types on the victim's system, rendering them inaccessible without the decryption key. Although the technical details are limited, the use of HoeflerText notifications suggests an innovative vector to increase user interaction or bypass some security controls by masquerading as legitimate browser notifications. The campaign is categorized as low severity, with no known exploits in the wild beyond the malspam distribution. The threat level and analysis scores indicate moderate confidence in the detection and characterization of this campaign. Since Locky ransomware is a destructive malware that impacts confidentiality and availability by encrypting data, it remains a significant threat despite the low severity rating assigned in this context, likely due to the age of the campaign (published in 2017) and the absence of active widespread exploitation currently reported.

For European organizations, the impact of Locky ransomware distributed via malspam with browser notification social engineering can be substantial. Successful infections can lead to widespread data encryption, causing operational disruption, data loss, and financial costs related to ransom payments and recovery efforts. Critical sectors such as healthcare, finance, manufacturing, and public services are particularly vulnerable due to their reliance on continuous data availability and the sensitivity of their information. The use of browser notifications as a vector may increase the likelihood of user interaction, potentially bypassing some traditional email filtering defenses. This could lead to increased infection rates if users are not adequately trained or if endpoint protections are insufficient. Additionally, ransomware incidents can trigger regulatory reporting requirements under GDPR, leading to reputational damage and potential fines. Although the campaign is dated, variants of Locky and similar ransomware continue to pose risks, and the tactics used here highlight the evolving social engineering methods attackers employ to increase infection success.

European organizations should implement multi-layered defenses against ransomware campaigns like this. Specific recommendations include: 1) Enhance email filtering to detect and block malspam, including heuristic and behavioral analysis to identify suspicious attachments and links. 2) Disable or restrict browser notifications from untrusted or unknown websites to prevent abuse of notification features like HoeflerText. 3) Conduct targeted user awareness training focusing on recognizing phishing attempts and suspicious browser notifications. 4) Employ endpoint detection and response (EDR) solutions capable of detecting ransomware behaviors such as rapid file encryption. 5) Maintain regular, tested backups stored offline or in immutable storage to enable recovery without paying ransom. 6) Apply the principle of least privilege to limit user permissions and prevent ransomware from spreading laterally. 7) Keep all software, including browsers and email clients, up to date with security patches to reduce exploitation opportunities. 8) Monitor network traffic for unusual patterns that may indicate ransomware activity. These measures, combined with incident response planning, will reduce the risk and impact of ransomware infections using novel social engineering vectors.