Magento’s API is a popular target for attackers. It repeatedly happens that malicious code is injected into content blocks through compromised interfaces. This code can be executed automatically in visitors’ browsers when an affected page is accessed – with potentially serious consequences for security, privacy, and customer trust.
However, simply removing the malicious code from the affected blocks is not enough. If the actual cause of the attack is not eliminated, the malicious code may be injected again at regular intervals. To permanently break this cycle, several targeted security measures are required.
Step 1: Remove malicious code from content blocks
As a first step, all affected CMS blocks should be carefully reviewed and cleaned. Malicious code is often embedded in HTML or JavaScript snippets and may be hidden, obfuscated, or deeply concealed within nested structures.
Tip: Before cleaning the affected blocks, make a backup of their current HTML content. This is particularly useful for complex layouts to prevent important content or formatting from being accidentally lost.
Step 2: Change admin passwords
After cleaning the system, all admin accounts should immediately be assigned new, secure passwords. Pay particular attention to the following points:
- Use complex and randomly generated passwords.
- Change the credentials for all admin accounts – including accounts that are rarely used.
- Remove unnecessary or outdated user accounts.
- Check whether additional protection such as two-factor authentication is available and enabled for all required users.
Every inadequately protected account can potentially serve as an entry point for another attack.
Step 3: Review and clean up API access
If the attack occurred through an API interface, or if this is suspected, all integrations and credentials must be thoroughly reviewed.
In the Magento backend, you can find the integrations under:
System → Extensions → Integrations
Pay particular attention to the following points:
- Delete all API integrations that are no longer required.
- Revoke unnecessary permissions from integrations that are still required.
- Rotate credentials and tokens for active integrations if a compromise cannot be ruled out.
- Review the assigned permissions and grant only the rights that are actually required.
This reduces the risk of an attacker gaining access to the system again using previously known or compromised credentials.
Step 4: Review and, if necessary, renew the Encryption Key
Another important aspect when investigating a compromised Magento system is the Encryption Key.
Why is the Encryption Key important?
Magento uses the Encryption Key, among other things, to encrypt certain sensitive configuration data. This can include, for example, credentials for external services.
If a system has been compromised and there is a specific suspicion that the Encryption Key has been exposed, key rotation should be considered as part of the incident response process. However, it is important to take into account which encrypted data and integrations are affected by the key change.
How to change the Encryption Key
The procedure depends on the Magento version being used. Before rotating the key, you should always create a complete and tested backup of the database and relevant files.
⚠️ Important: Changing the Encryption Key is not a measure that should be performed blindly after a compromised system has been discovered. First check the Magento version, existing integrations, and the impact on encrypted configuration values.
Additional measures after a Magento hack
Cleaning CMS blocks and changing credentials are only part of a comprehensive security analysis. In the event of an actual security incident, the server, file system, database, cron jobs, and logs should also be examined for signs of manipulation.
- Check Magento, extensions, and Composer dependencies for known security vulnerabilities.
- Check for unusual files and modifications within the Magento file system.
- Review cron jobs and other automated processes.
- Analyze server, web server, and Magento logs for suspicious access attempts.
- Check admin users and API integrations for unknown entries.
- Rotate any other compromised credentials, such as database, SSH, SMTP, or external API credentials.
- Update Magento and all security-relevant extensions to supported versions.
Conclusion: Security does not end with cleanup
A successful Magento attack can have far-reaching consequences. Simply removing visible malicious code may not eliminate the actual cause of the compromise. This creates the risk that the attacker could regain access and inject the malicious code again.
A sustainable cleanup should therefore cover several levels: removing the malicious code, securing and rotating compromised credentials, reviewing API integrations, and conducting a thorough analysis of the entire system. In the event of a confirmed security incident, it should also be assessed whether rotation of the Encryption Key is necessary.
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