The provided information describes a malspam campaign dated July 13, 2016, involving malicious Windows Script Files (.wsf). Malspam campaigns typically distribute malware via email attachments or links, aiming to infect recipients who open the malicious files. The .wsf file format is a Windows scripting file that can contain scripts written in multiple scripting languages such as VBScript or JScript, which can execute arbitrary code on the victim's machine. This campaign likely involved sending emails with .wsf attachments or links to such files, attempting to trick users into executing them, thereby compromising their systems. The campaign is classified as malware-related by CIRCL, with a low severity rating and no known exploits in the wild beyond the campaign itself. No specific affected software versions or vulnerabilities are listed, indicating this is more of a distribution vector for malware rather than an exploitation of a particular software flaw. The threat level is moderate (3 on an unspecified scale), but no detailed technical analysis or indicators of compromise are provided. Given the age of the campaign (2016), it likely targeted Windows environments where users might have been less aware of the risks of executing .wsf files from untrusted sources.

For European organizations, the impact of this malspam campaign would primarily be the risk of endpoint compromise through user interaction with malicious attachments. Successful execution of .wsf files can lead to malware installation, potentially resulting in data theft, system disruption, or use of the infected machine as part of a botnet. Although the severity is rated low and no widespread exploitation is noted, organizations with less mature email filtering and endpoint protection at the time could have been vulnerable. The campaign's impact would be more significant in sectors with high email volumes and less user awareness about scripting file risks. Additionally, any resulting malware infections could lead to secondary impacts such as lateral movement within networks, data exfiltration, or ransomware deployment, depending on the payload delivered by the .wsf scripts.

To mitigate threats from .wsf malspam campaigns, European organizations should implement advanced email filtering solutions that block or quarantine emails containing suspicious attachments, especially executable scripts like .wsf files. Endpoint protection platforms should be configured to detect and block execution of scripting files from untrusted sources. User awareness training is critical to educate employees about the risks of opening unexpected attachments, particularly script files. Network segmentation and application whitelisting can limit the impact of any successful infection. Additionally, disabling Windows Script Host (WSH) where not needed can prevent execution of .wsf files altogether. Regular patching and updating of email clients and security products will help reduce the attack surface. Monitoring for unusual script execution and network traffic can aid in early detection of infections stemming from such campaigns.