This threat pertains to a malspam campaign identified on September 6, 2016, which distributes malicious scripts packaged as Windows Script Files (.wsf) inside compressed ZIP archives. The campaign uses email subject lines resembling invoices, specifically formatted as "Invoice INV[x]", to entice recipients into opening the attachments. Upon extraction and execution of the .wsf file, the malware targets Windows platforms, both 32-bit and 64-bit architectures. The use of .wsf files is notable because they can contain scripts written in multiple scripting languages (such as VBScript or JScript), allowing attackers to execute arbitrary code on the victim's machine. The campaign is categorized as low severity with no known exploits in the wild beyond the malspam distribution itself. There are no specific affected software versions or patches associated with this threat, indicating it relies on social engineering and user interaction rather than exploiting a software vulnerability. The threat level is rated as 3 on an unspecified scale, suggesting a relatively low technical sophistication or impact compared to more severe malware campaigns. The absence of detailed technical indicators or CWEs limits the ability to analyze the malware's internal mechanisms or payloads further.

For European organizations, the primary risk from this malspam campaign is the potential for initial infection through user interaction, specifically opening malicious email attachments. If successful, the malware could compromise endpoint systems, potentially leading to unauthorized access, data theft, or further malware deployment. However, given the low severity rating and lack of known exploits in the wild, the overall impact is likely limited and localized to users who fall victim to the phishing attempt. Organizations with strong email filtering, user awareness training, and endpoint protection are less likely to be affected. Nonetheless, any successful compromise could disrupt business operations, especially if the malware facilitates lateral movement or data exfiltration. The campaign's reliance on invoice-themed emails targets financial or administrative personnel, which could increase the risk to departments handling sensitive financial data.

To mitigate this threat effectively, European organizations should implement targeted email security measures that specifically scan and block compressed archives containing script files such as .wsf. Advanced email gateways should be configured to detect and quarantine emails with suspicious subject lines resembling invoices, especially those containing executable script attachments. User awareness training should emphasize the risks of opening unexpected invoice emails and attachments, highlighting the specific threat of .wsf files within ZIP archives. Endpoint protection solutions should be configured to detect and block execution of script files from email downloads or temporary folders. Additionally, organizations should enforce application whitelisting policies that restrict execution of script files unless explicitly approved. Regular phishing simulation exercises can help reinforce user vigilance against such malspam campaigns. Network monitoring for unusual outbound connections from endpoints can also help detect potential post-infection activity.