Malware
SessionManager
A malicious IIS module that allows up/download of files, remote command execution, and using the compromised server as a hop into the network behind.
SessionManager is a Windows malware family operated by Gelsemium.
Background
A rogue IIS module that supports uploading and downloading files, running commands remotely, and pivoting through the compromised server into the network behind it.
Source: Malpedia (Fraunhofer FKIE).