How Attackers Use XLL Malware to Infect Systems

In recent months, we have seen a growth in malware campaigns using malicious Microsoft Excel add-in (XLL) files to infect systems. This technique is tracked in MITER ATT&CK as T1137.006. The idea behind such add-ins is that they contain high-performance functions and can be called from an Excel worksheet via an application programming interface (API). … Read more