CVE-2019-9858: Path Traversal

Remote code execution was discovered in Horde Groupware Webmail 5.2.22 and 5.2.17. Horde/Form/Type.php contains a vulnerable class that handles image upload in forms. When the HordeFormTypeimage method onSubmit() is called on uploads, it invokes the functions getImage() and getUpload(), which uses unsanitized user input as a path to save the image. The unsanitized POST parameter object[photo][img][file] is saved in the $upload[img][file] PHP variable, allowing an attacker to manipulate the $tmpfile passed to moveuploadedfile() to save the uploaded file. By setting the parameter to (for example) ../usr/share/horde/static/bd.php, one can write a PHP backdoor inside the web root. The static/ destination folder is a good candidate to drop the backdoor because it is always writable in Horde installations. (The unsanitized POST parameter went probably unnoticed because it's never submitted by the forms, which default to securely using a random path.)