Executive Summary

The WordPress Time Capsule Plugin version 1.21.16 contains an authentication bypass vulnerability. This flaw allows unauthenticated attackers to gain administrative access by sending a specially crafted POST request with the IWP_JSON_PREFIX header.

By exploiting this vulnerability, attackers can obtain valid administrator session cookies and access the WordPress dashboard without providing any credentials.

Once authenticated, attackers can perform administrative actions, including uploading malicious shells to execute arbitrary commands on the server.

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Impact Analysis

This vulnerability can have severe impacts as it allows attackers to bypass authentication and gain full administrative access to your WordPress site.

• Attackers can control the WordPress dashboard without credentials.
• They can upload malicious shells to execute arbitrary commands on your server.
• This can lead to complete site compromise, data theft, defacement, or further exploitation of your server.

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Detection Guidance

This vulnerability can be detected by monitoring for suspicious POST requests containing the IWP_JSON_PREFIX header sent to the WordPress Time Capsule Plugin endpoints.

One way to detect exploitation attempts is to analyze web server logs for POST requests with the IWP_JSON_PREFIX header.

• Use command-line tools like grep to search for the IWP_JSON_PREFIX header in access logs, for example: grep -i 'IWP_JSON_PREFIX' /var/log/apache2/access.log
• Monitor for unusual administrative session cookies or unexpected admin dashboard access without proper authentication.

Additionally, the proof-of-concept exploit script referenced in Resource 1 can be used in a controlled environment to verify if the system is vulnerable.

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Mitigation Strategies

Immediate mitigation steps include updating the WordPress Time Capsule Plugin to a version later than 1.21.16 where this vulnerability is fixed.

If an update is not immediately possible, restrict access to the WordPress admin dashboard and plugin endpoints by IP whitelisting or firewall rules to prevent unauthorized POST requests.

Monitor and invalidate any suspicious administrator session cookies to prevent unauthorized access.

Review server logs for signs of exploitation and remove any unauthorized web shells or malicious files if found.

Consider temporarily disabling the Time Capsule Plugin until a patch or update is applied.

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Compliance Impact

The vulnerability allows unauthenticated attackers to gain administrative access to the WordPress dashboard by bypassing authentication mechanisms. This unauthorized access can lead to exposure or manipulation of sensitive data managed through the WordPress site.

Such unauthorized administrative access could potentially result in violations of compliance requirements under standards like GDPR or HIPAA, which mandate strict controls over access to personal or protected health information. If attackers exploit this vulnerability to access or alter sensitive data, organizations may fail to meet these regulatory obligations.

However, the provided information does not explicitly detail the impact on compliance frameworks or specific regulatory consequences.

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