I have the same problem.
I receive no advice if I open an infected acad.lsp (or acadapp.lsp) file, e.g. through notepad, but if I perform a manual scan on the single file, then Avast recognizes it. It is very strange, maybe Avast does not search for viruses in *.lsp files!
I have this virus spreading all along my folders, before I noticed this problem. Please tell me how I can force my antivirus to scan *.lsp files too.
In virustotal you can find it here:
https://www.virustotal.com/#/file/e2b532574072ce0860c99a5edcf0b78439d3527b5c7c6fe4bd0a6282974fb64a/detectionHashes:
CRC32: 823E1497
MD5: 4A4136DE9925FFFD8D12AFD0D3252A89
SHA-1: A7CEB9C6C7D5A7AA3DBB76C672E8134741F852CB
SHA-256: E2B532574072CE0860C99A5EDCF0B78439D3527B5C7C6FE4BD0A6282974FB64A
I can send a sample of this virus file, since I kept a copy.