Can you explain this vulnerability to me?

CVE-2025-56425 is an SMTP Injection vulnerability in the enaio® AppConnector component affecting versions 10.10.0.183 and earlier of enaio® 10.10, 11.0.0.183 and earlier of enaio® 11.0, and 11.10.0.183 and earlier of enaio® 11.10. The vulnerability allows authenticated remote attackers to inject arbitrary SMTP commands via crafted input to the /osrest/api/organization/sendmail endpoint. This happens because the webserver does not properly validate user inputs before sending emails, allowing attackers to manipulate SMTP communication by injecting commands that can alter the email sender, recipient, and content. The injection exploits the reuse of the 'receiver' attribute without sanitization, enabling spoofing and manipulation of email headers and content, including HTML styling to hide or alter the appearance of the email. This can be used to send forged emails that appear legitimate, facilitating phishing attacks. [1]

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How can this vulnerability impact me? :

This vulnerability can impact you by allowing attackers who have authenticated access to the vulnerable enaio® AppConnector API to send forged emails with manipulated sender and recipient information. This can lead to successful phishing attacks, where malicious emails appear legitimate and trick recipients into clicking harmful links or disclosing sensitive information. The ability to inject arbitrary SMTP commands also means attackers can manipulate email content and headers, potentially damaging your organization's reputation, enabling social engineering attacks, and compromising email trustworthiness. [1]

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How can this vulnerability be detected on my network or system? Can you suggest some commands?

Detection of this vulnerability involves monitoring for unusual or crafted HTTP POST requests to the vulnerable API endpoint `/osrest/api/organization/sendmail` that include suspicious SMTP command injections in the parameters, especially the `receiver` attribute. Network or web server logs can be inspected for such requests containing SMTP control characters like '\r\n' or unusual email header manipulations. Specific commands depend on your environment, but for example, using curl to test the endpoint with crafted input or using log analysis tools to search for POST requests to `/osrest/api/organization/sendmail` containing suspicious payloads can help detect exploitation attempts. [1]

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What immediate steps should I take to mitigate this vulnerability?

The immediate mitigation step is to update the enaio® AppConnector component to versions 10.10.0.184, 11.0.0.184, or 11.10.0.184 or later, which include proper input validation to prevent SMTP injection. Until the update can be applied, restrict access to the vulnerable API endpoint to trusted authenticated users only, monitor logs for suspicious activity, and consider implementing input validation or filtering at the webserver or application firewall level to block SMTP injection attempts. [1]

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How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:

The provided resources do not explicitly discuss how the SMTP injection vulnerability in enaio® AppConnector affects compliance with common standards and regulations such as GDPR or HIPAA. However, since the vulnerability allows authenticated attackers to inject arbitrary SMTP commands and manipulate email content, it could potentially lead to phishing attacks and unauthorized disclosure or manipulation of sensitive information, which may impact compliance with data protection regulations. No direct statements about compliance impact are given. [1, 2]

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