The threat described is a malspam campaign identified on August 25, 2016, involving malicious spam emails that deliver JavaScript (.js) files compressed within ZIP archives. This campaign, labeled "Contract," uses social engineering tactics by naming the attachments or email content to suggest legitimate contractual documents, enticing recipients to open the ZIP file and execute the JavaScript payload. The execution of the JavaScript file can lead to the download and installation of malware on the victim's system. Although specific malware types or payloads are not detailed, such campaigns typically aim to establish persistence, steal information, or enable further compromise. The campaign is classified as malware with a low severity rating by the source, CIRCL, and no known exploits in the wild have been reported. The threat level is moderate (3 out of an unspecified scale), and no specific affected software versions or vulnerabilities are mentioned, indicating this is a generic delivery mechanism rather than an exploit of a particular software flaw. The lack of detailed technical indicators or CWEs suggests limited available intelligence on the exact malware behavior or capabilities.

For European organizations, this malspam campaign poses a risk primarily through user interaction, as it relies on recipients opening malicious attachments. The impact includes potential malware infection leading to data theft, unauthorized access, or disruption of operations. Although the severity is low, organizations with less mature email security controls or insufficient user awareness training may be more vulnerable. The campaign could affect confidentiality if sensitive data is exfiltrated, integrity if systems are altered, and availability if malware disrupts services. Given the generic nature of the attack vector, any organization using email as a communication tool is potentially at risk, especially those in sectors handling contracts and legal documents where such attachments are common. The impact is mitigated by the need for user action and the absence of automated exploitation.

To mitigate this threat, European organizations should implement advanced email filtering solutions capable of detecting and quarantining suspicious ZIP attachments containing JavaScript files. Employing sandboxing technologies to analyze attachments before delivery can prevent malicious payload execution. User awareness training should emphasize the risks of opening unexpected or unsolicited attachments, especially those compressed in ZIP files with script files inside. Disabling the execution of JavaScript files from email attachments or restricting script execution policies on endpoints can reduce risk. Organizations should also maintain up-to-date endpoint protection solutions with behavioral detection capabilities to identify and block malware activity post-execution. Regularly reviewing and updating email security policies to block or flag potentially dangerous file types is recommended. Incident response plans should include procedures for malspam campaigns to quickly isolate and remediate infected systems.