Exploit:Win32/ShellCode.gen!B is a generic detection for files that have malicious shellcode. These shellcodes may be found within other types of files such as documents, for example, specially-crafted PDF files.

Windows Defender detects and removes this threat.

Exploit:Win32/ShellCode.gen!C is a generic detection for JavaScript files that have malicious code. Generally, attackers use this malicious code to infect your computer with other malware.

These files are often downloaders which use the malicious code to exploit vulnerabilities in various software.

A vulnerability is like a hole in your software that malware can use (or exploit) to get on your computer. These holes are fixed by installing updates to the vulnerable software; this is why it is extremely important to keep all of the programs on your computer up to date.

See here for information on how to update some software.

As this is a generic detection, we cannot identify the precise files that use this code or the particular exploits that the code uses.

Exploit:Win32/ShellCode.gen!D is a generic detection for files that contain a malicious shellcode.