CVE-2020-13625

PHPMailer before 6.1.6 contains an output escaping bug when the name of a file attachment contains a double quote character. This can result in the file type being misinterpreted by the receiver or any mail relay processing the message.

PHPMailer before 6.1.6 contains an output escaping bug when the name of a file attachment contains a double quote character. This can result in the file type being misinterpreted by the receiver or any mail relay processing the message.

### Impact CWE-116: Incorrect output escaping. An attachment added like this (note the double quote within the attachment name, which is entirely valid): $mail->addAttachment('/tmp/attachment.tmp', 'filename.html";.jpg'); Will result in a message containing these headers: Content-Type: application/octet-stream; name="filename.html";.jpg" Content-Disposition: attachment; filename="filename.html";.jpg" The attachment will be named `filename.html`, and the trailing `";.jpg"` will be ignored. Mail filters that reject `.html` attachments but permit `.jpg` attachments may be fooled by this. Note that the MIME type itself is obtained automatically from the *source filename* (in this case `attachment.tmp`, which maps to a generic `application/octet-stream` type), and not the *name* given to the attachment (though these are the same if a separate name is not provided), though it can be set explicitly in other parameters to attachment methods. ### Patches Patched in PHPMailer 6.1.6 by escaping double quotes within the name using a backslash, as per RFC822 section 3.4.1, resulting in correctly escaped headers like this: Content-Type: application/octet-stream; name="filename.html\";.jpg" Content-Disposition: attachment; filename="filename.html\";.jpg" ### Workarounds Reject or filter names and filenames containing double quote (`"`) characters before passing them to attachment functions such as `addAttachment()`. ### References [CVE-2020-13625](https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2020-13625). [PHPMailer 6.1.6 release](https://github.com/PHPMailer/PHPMailer/releases/tag/v6.1.6) ### For more information If you have any questions or comments about this advisory: * Open an issue in [the PHPMailer repo](https://github.com/PHPMailer/PHPMailer/issues)

### Impact CWE-116: Incorrect output escaping. An attachment added like this (note the double quote within the attachment name, which is entirely valid): $mail->addAttachment('/tmp/attachment.tmp', 'filename.html";.jpg'); Will result in a message containing these headers: Content-Type: application/octet-stream; name="filename.html";.jpg" Content-Disposition: attachment; filename="filename.html";.jpg" The attachment will be named `filename.html`, and the trailing `";.jpg"` will be ignored. Mail filters that reject `.html` attachments but permit `.jpg` attachments may be fooled by this. Note that the MIME type itself is obtained automatically from the *source filename* (in this case `attachment.tmp`, which maps to a generic `application/octet-stream` type), and not the *name* given to the attachment (though these are the same if a separate name is not provided), though it can be set explicitly in other parameters to attachment methods. ### Patches Patched in PHPMailer 6.1.6 by escaping double quotes within the name using a backslash, as per RFC822 section 3.4.1, resulting in correctly escaped headers like this: Content-Type: application/octet-stream; name="filename.html\";.jpg" Content-Disposition: attachment; filename="filename.html\";.jpg" ### Workarounds Reject or filter names and filenames containing double quote (`"`) characters before passing them to attachment functions such as `addAttachment()`. ### References [CVE-2020-13625](https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2020-13625). [PHPMailer 6.1.6 release](https://github.com/PHPMailer/PHPMailer/releases/tag/v6.1.6) ### For more information If you have any questions or comments about this advisory: * Open an issue in [the PHPMailer repo](https://github.com/PHPMailer/PHPMailer/issues)

PHPMailer versiones anteriores a 6.1.6, contiene un bug de escape de salida cuando el nombre de un archivo adjunto contiene un carácter de comillas dobles. Esto puede resultar en que el tipo de archivo esta siendo malinterpretado por el receptor o que cualquier retransmisión de correo procese el mensaje