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Backdoor

wp-config.php Backdoor

Malicious PHP code is inserted into wp-config.php to load malware before WordPress fully starts.

Criticalseverity
Backdoorthreat type
Manualrecommended review

Symptoms

These are common signs associated with this type of WordPress compromise. The exact behavior can vary by hosting setup, cache layer, plugins and how the attacker configured the payload.

  • Malware executes even when plugins and themes are disabled.
  • Suspicious PHP appears before or after normal wp-config settings.
  • Site behavior changes globally.

Technical overview

Because wp-config.php loads early, attackers use it as a reliable persistence point after gaining file access.

Important: visible symptoms are rarely the whole incident. A safe recovery should identify both the payload and the persistence mechanism that allowed it to run.

Indicators of compromise

During investigation, these indicators are commonly reviewed. They do not prove compromise alone, but they help map scope and root cause.

eval/base64 code in wp-config.php
Remote include calls
Unexpected require statements
Unknown constants
Modified timestamp outside maintenance window

Investigation process

WP•FIX treats this as an incident, not a simple file deletion task. The review normally includes WordPress core integrity, theme and plugin files, uploads, database options, users, cron events, redirects, cache layers and the most likely entry point.

Recovery process

  • Create a safe recovery point before changing production data.
  • Remove malicious files, scripts, database payloads and persistence mechanisms.
  • Replace compromised components with clean versions where appropriate.
  • Review administrator users, credentials and access paths.
  • Harden the site and document the recovery path.

Prevention

Prevention depends on the root cause. Common controls include removing nulled components, updating vulnerable plugins, reducing administrator access, hardening login paths, adding monitoring and keeping verified backups.

FAQ

Can this be cleaned with a plugin?

A plugin can help detect common indicators, but serious WordPress incidents need manual review of files, database records, users, access logs, redirects and persistence mechanisms.

Why does this infection come back?

Reinfection usually means the backdoor, vulnerable entry point, compromised credentials or database payload was not removed during the first cleanup.

Can WP•FIX help with this threat?

Yes. WP•FIX can investigate the symptoms, map the scope, remove malicious payloads and recommend hardening steps to reduce reinfection risk.

Need help with wp-config.php Backdoor?

If this looks like your site, open an incident and include the symptoms, URL and any warning messages.

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