Fix h1 report 175626

Deserialization of Untrusted Data
---------------------------------

HackerOne user Nicolas Grégoire - Agarri has reported that Revive Adserver
was unserializing untrusted data submitted via cookies in the delivery
scripts. An attacker could use such vector to either perform generic RCE
attacks (e.g. when a vulnerable PHP version is being used) or,
potentially, application-specific attacks.

CWE-ID: CWE-502

CVSSv3 Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
CVSSv3 Base Score: 9.8
CVSSv3 Temporal Score: 8.5

Author: mbeccati

lib/max/Delivery/querystring.php

@@ -71,10 +71,12 @@ function MAX_querystringConvertParams()
         $n = isset($aGet[$conf['var']['n']]) ? $aGet[$conf['var']['n']] : '';
     }
     if (!empty($n) && !empty($_COOKIE[$conf['var']['vars']][$n])) {
-        $aVars = unserialize(stripslashes($_COOKIE[$conf['var']['vars']][$n]));
-        foreach ($aVars as $name => $value) {
-            if (!isset($_GET[$name])) {
-                $aGet[$name] = $value;
+        $aVars = json_decode($_COOKIE[$conf['var']['vars']][$n], true);
+        if (is_array($aVars)) {
+            foreach ($aVars as $name => $value) {
+                if (!isset($_GET[$name])) {
+                    $aGet[$name] = $value;
+                }
             }
         }
     }

www/delivery_dev/afr.php

@@ -32,20 +32,24 @@
 $banner = MAX_adSelect($what, $campaignid, $target, $source, $withtext, $charset, $context, true, $ct0, $loc, $referer);
 
 // Send cookie if needed
-if (!empty($banner['html']) && !empty($n)) {
-    // Send bannerid headers
-    $cookie = array();
-    $cookie[$conf['var']['adId']] = $banner['bannerid'];
-    // Send zoneid headers
-    if ($zoneid != 0) {
-        $cookie[$conf['var']['zoneId']] = $zoneid;
+if (!empty($n)) {
+    if (!empty($banner['html'])) {
+        // Send bannerid headers
+        $cookie = array();
+        $cookie[$conf['var']['adId']] = $banner['bannerid'];
+        // Send zoneid headers
+        if ($zoneid != 0) {
+            $cookie[$conf['var']['zoneId']] = $zoneid;
+        }
+        // Send source headers
+        if (!empty($source)) {
+            $cookie[$conf['var']['channel']] = $source;
+        }
+        // Set the cookie
+        MAX_cookieAdd($conf['var']['vars'] . "[$n]", json_encode($cookie, JSON_UNESCAPED_SLASHES));
+    } else {
+        MAX_cookieUnset($conf['var']['vars'] . "[$n]");
     }
-    // Send source headers
-    if (!empty($source)) {
-        $cookie[$conf['var']['channel']] = $source;
-    }
-    // Set the cookie
-    MAX_cookieAdd($conf['var']['vars'] . "[$n]", serialize($cookie));
 }
 
 MAX_cookieFlush();

www/delivery_dev/avw.php

@@ -84,7 +84,7 @@
         MAX_Delivery_log_logAdImpression($row['bannerid'], $zoneid);
     }
     // Redirect to the banner
-    MAX_cookieAdd($conf['var']['vars'] . "[$n]", serialize($cookie));
+    MAX_cookieAdd($conf['var']['vars'] . "[$n]", json_encode($cookie, JSON_UNESCAPED_SLASHES));
     MAX_cookieFlush();
     if ($row['bannerid'] == '') {
        if ($row['default_banner_image_url'] != '') {
@@ -98,7 +98,7 @@
         MAX_redirect($creativeURL);
     }
 } else {
-	MAX_cookieAdd($conf['var']['vars'] . "[$n]", 'DEFAULT');
+	MAX_cookieUnset($conf['var']['vars'] . "[$n]");
 	MAX_cookieFlush();
 	// Show 1x1 Gif, to ensure not broken image icon is shown.
 	MAX_commonDisplay1x1();