Add method for checking version from changelogs

Author: rastating

lib/wpxf/wordpress/fingerprint.rb

@@ -54,6 +54,17 @@ def check_plugin_version_from_readme(name, fixed = nil, introduced = nil)
     check_version_from_readme(:plugin, name, fixed, introduced)
   end
 
+  # Checks a plugin's changelog for a vulnerable version.
+  # @param plugin_name [String] the name of the plugin.
+  # @param file_name [String] the name of the file that contains the changelog.
+  # @param fixed [String] the version the vulnerability was fixed in.
+  # @param introduced [String] the version the vulnerability was introduced in.
+  # @return [Symbol] :unknown, :vulnerable or :safe.
+  def check_plugin_version_from_changelog(plugin_name, file_name, fixed = nil, introduced = nil)
+    changelog = normalize_uri(wordpress_url_plugins, plugin_name, file_name)
+    check_version_from_custom_file(changelog, /=\s(\d\.\d(\.\d)?)\s=/, fixed, introduced)
+  end
+
   # Checks a custom file for a vulnerable version.
   # @param url [String] the relative path of the file.
   # @param regex [Regexp] the regular expression to extract the version.