Security question regarding a couple of plugins

I use wordfence on my multi-site and wordfence is reporting to me that a couple of the files from your plugins may contain malicious code. Can you confirm that these files have not been hacked and not malicious.

Below is the error and the files (3):

The files below may contain malicious executable code:

Filename: wp-content/plugins/user-reports/lib/dompdf/include/cpdf_adapter.cls.php

Filename: wp-content/plugins/user-reports/lib/dompdf/lib/class.pdf.php

Filename: wp-content/plugins/pro-sites/pro-sites-files/tcpdf/tcpdf.php

This file is a PHP executable file and contains the word 'eval' (without quotes) and the word 'base64_decode' (without quotes). The eval() function along with an encoding function like the one mentioned are commonly used by hackers to hide their code.