diff --git a/wp-includes/post.php b/wp-includes/post.php
index 7b6575366a..d0ecd2e04e 100644
--- a/wp-includes/post.php
+++ b/wp-includes/post.php
@@ -4992,12 +4992,9 @@ function wp_get_attachment_url( $post_id = 0 ) {
 		$url = get_the_guid( $post->ID );
 	}
 
-	/*
-	 * If currently on SSL, prefer HTTPS URLs when we know they're supported by the domain
-	 * (which is to say, when they share the domain name of the current SSL page).
-	 */
-	if ( is_ssl() && 'https' !== substr( $url, 0, 5 ) && parse_url( $url, PHP_URL_HOST ) === $_SERVER['HTTP_HOST'] ) {
-		$url = set_url_scheme( $url, 'https' );
+	// On SSL front-end, URLs should be HTTPS.
+	if ( is_ssl() && ! is_admin() && 'wp-login.php' !== $GLOBALS['pagenow'] ) {
+		$url = set_url_scheme( $url );
 	}
 
 	/**
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 794dfb907b..7d599bd82c 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.3-alpha-32341';
+$wp_version = '4.3-alpha-32342';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.