This threat involves malware associated with the Locky ransomware family and the Trickbot banking Trojan, identified in October 2017. The Locky ransomware is known for encrypting victims' files and demanding ransom payments for decryption keys, while Trickbot is a modular banking Trojan that facilitates credential theft, lateral movement, and deployment of additional malware. The specific sample referenced appears to be linked to a phishing campaign using email subjects and attachments mimicking invoice status notifications (e.g., "Status of invoice A2171234-56" with an HTML attachment "A2171234-56.html"), a common social engineering tactic to entice users to open malicious content. The mention of "M2M" and identifiers like "asasin" and "mac1" may refer to internal campaign or malware variant tags. Although no affected software versions or patches are listed, the malware operates by exploiting user interaction to execute malicious payloads delivered via email. The threat level is indicated as moderate (3), and the severity is marked low, reflecting the need for user action to trigger infection and the absence of known exploits in the wild at the time of reporting. The combination of Trickbot and Locky suggests a multi-stage attack where Trickbot may be used to gain initial access or harvest credentials, followed by Locky ransomware deployment to maximize impact.

For European organizations, this threat poses risks primarily through phishing campaigns targeting employees with fake invoice notifications, potentially leading to ransomware infections and data encryption. The impact includes operational disruption due to encrypted files, potential data loss if backups are inadequate, financial losses from ransom payments or recovery costs, and reputational damage. Trickbot's credential theft capabilities could further compromise network security, enabling attackers to move laterally and escalate privileges, potentially affecting sensitive systems and data. Organizations in sectors with high email communication volumes and invoice processing, such as finance, manufacturing, and services, are particularly vulnerable. The low severity rating suggests that while the threat requires user interaction, the widespread use of phishing and ransomware in Europe means that even low-severity threats can have significant cumulative effects if not mitigated.

To mitigate this threat, European organizations should implement advanced email filtering solutions capable of detecting and quarantining phishing emails with malicious attachments or links. User awareness training focusing on recognizing invoice-related phishing attempts is critical, emphasizing caution with unexpected or unusual invoice emails and attachments. Deploy endpoint protection platforms with behavioral detection to identify ransomware and banking Trojan activities. Network segmentation and strict access controls can limit lateral movement if Trickbot compromises credentials. Regular, tested backups stored offline or in immutable storage are essential to recover from ransomware without paying ransom. Additionally, organizations should monitor for indicators of compromise related to Trickbot and Locky, including unusual network traffic and file encryption activities. Applying the principle of least privilege and enforcing multi-factor authentication can reduce the risk of credential theft exploitation.