As recently disclosed (https://vulnsec.com/2016/osx-apps-vulnerabilities/) you may be already be aware of a vulnerability in Sparkle that exposes a large number of applications to man-in-the-middle (MiTM) attacks over insecure HTTP channels.
In order to identify Applications that are susceptible to MiTM attacks that install malicious code in the Sparkle software framework invoke the below from a terminal window. From the output we are looking for applications to which the version string is prior to 1.13.1 to which these will be vulnerable if set to load over HTTP.
find /Applications -path '*Autoupdate.app/Contents/Info.plist' -exec echo {} \; -exec grep -A1 CFBundleShortVersionString '{}' \; | grep -v CFBundleShortVersionString
The applications ‘Info.plist’ file will have a ‘SUFeedURL’ key which can identify any assets that are being loaded over unsecured HTTP. Alternatively, you can attempt to update the application and perform a packet capture using a utility such as Wireshark to determine if the HTTP protocol is being used.
A list of applications that are dependent on Sparkle can be found here, but not all of these may be communicating over insecure HTTP.