diff --git a/src/app/Jobs/User/CreateJob.php b/src/app/Jobs/User/CreateJob.php
--- a/src/app/Jobs/User/CreateJob.php
+++ b/src/app/Jobs/User/CreateJob.php
@@ -67,6 +67,24 @@
             return;
         }
 
+        if (!$user->isActive() && ($script = \config('services.abuse-check'))) {
+            exec($script . ' ' . $this->userId, $output, $retval);
+
+            // We expect error code 0, so an error in the script does not cause user suspension
+            // FIXME: Should an error stop the process of user creation or not?
+            if ($retval > 0) {
+                throw new \Exception("Abuse check failed for user {$this->userId}.");
+            }
+
+            // The script should output "ABUSE" if the user is a suspected spammer
+            if (strpos(implode('', $output), 'ABUSE') !== false) {
+                $user->status |= \App\User::STATUS_SUSPENDED;
+            }
+        }
+
+        $user->status |= \App\User::STATUS_ACTIVE;
+        $user->save();
+
         if ($withLdap && !$user->isLdapReady()) {
             \App\Backends\LDAP::createUser($user);
 
@@ -80,9 +98,7 @@
             }
 
             $user->status |= \App\User::STATUS_IMAP_READY;
+            $user->save();
         }
-
-        $user->status |= \App\User::STATUS_ACTIVE;
-        $user->save();
     }
 }
diff --git a/src/config/services.php b/src/config/services.php
--- a/src/config/services.php
+++ b/src/config/services.php
@@ -14,6 +14,8 @@
     |
     */
 
+    'abuse-check' => env('ABUSE_CHECK', null),
+
     'mailgun' => [
         'domain' => env('MAILGUN_DOMAIN'),
         'secret' => env('MAILGUN_SECRET'),