漏洞描述

Horde Groupware Webmail是美国Horde公司的一套基于浏览器的企业级通信套件。 Horde Groupware Webmail中存在代码注入漏洞。该漏洞源于外部输入数据构造代码段的过程中，网络系统或产品未正确过滤其中的特殊元素。攻击者可利用该漏洞生成非法的代码段，修改网络系统或组件的预期的执行控制流。

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 Horde_Form_Type_image 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 $tmp_file passed to move_uploaded_file() 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.)