Arbitrary File Deletion via Path Traversal in image-edit.php

How it was found

Summary:

The vulnerability is located in the /libraries/image-editor/image-edit.php script:

161.		if (@copy ( ICMS_IMANAGER_FOLDER_PATH . '/temp/' . $simage_temp, $categ_path . $simage->getVar ( 'image_name' ) )) {
162.			if (@unlink ( ICMS_IMANAGER_FOLDER_PATH . '/temp/' . $simage_temp )) {
163.				$msg = _MD_AM_DBUPDATED;

[...]

190.		} else {
191.			if (copy ( ICMS_IMANAGER_FOLDER_PATH . '/temp/' . $simage_temp, $categ_path . $imgname )) {
192.				@unlink ( ICMS_IMANAGER_FOLDER_PATH . '/temp/' . $simage_temp );
193.			}

User input passed through the "image_temp" parameter is not properly sanitized before being used in a call to the unlink() function at lines 162 and 192. This can be exploited to carry out Path Traversal attacks and delete arbitrary files in the context of the web server process.

NOTE: before being deleted, the file will be copied into the /uploads/imagemanager/logos/ directory. As such, by firstly deleting the index.html file in that directory, it might be possible to disclose the content of arbitrary files in case the web server allows for directory listing.

ImpressCMS branch :

The vulnerability has been tested and confirmed on ImpressCMS version 1.4.2 (the latest at the time of writing).

Steps To Reproduce:

1. Login into the application as any user (this should work both for Webmasters and Registered Users)
2. Go to: http://[impresscms]/libraries/image-editor/image-edit.php?op=save&image_id=1&image_temp=../../../mainfile.php
3. The mainfile.php script will be deleted, rendering the website unusable

Impact

This vulnerability might allow authenticated attackers to delete arbitrary files, potentially leading to a Denial of Service (DoS) condition or destruction of users data.