After getting a server token from ABM you need to follow some steps to extract information from token.

step 1. Clean the data : command -> grep -Eo '[A-Za-z0-9+/=]+' smime.p7m > cleaned_smime.p7m

step 2. Base64 Decode : command -> base64 -d cleaned_smime.p7m > decoded_test_smime.p7m

step 3. Decrypt the data using your private key and cert key : command -> openssl smime -decrypt -in decoded_test_smime.p7m -inform DER -inkey private_key.pem -certfile cert_key.pem -out extracted_content.txt

After completing this steps you get a extracted data into extracted_content.txt file.