Try this: copy the file /themes/asteria-lite/asteria-config.php to /themes/asteria-lite/asteria-config.txt and visit that in your browser.
http://your-wordpress-url-here/wp-content/themes/asteria-lite/asteria-config.txt
The visit this link in another tab or browser window.
https://themes.svn.wordpress.org/asteria-lite/0.8/asteria-config.php
Do a stare-and-compare or even save those to files to your PC or Mac. Then examine the 2 files. If they appear to be the same then it's probably a false positive. If your copy is different then something may be going on with your installation.