Pear HTTP_Upload v1.0.0b3 Arbitrary File Upload Vulnerability

[+]################################################################################################
[+] Credits: John Page AKA Hyp3rlinx
[+] Website: hyp3rlinx.altervista.org
[+] Source: http://hyp3rlinx.altervista.org/advisories/PEAR-HTTP_UPLOAD-ARBITRARY-FILE-UPLOAD.txt
[+] ISR: ApparitionSEC
[+]################################################################################################



Vendor:
============
pear.php.net



Product:
====================
HTTP_Upload v1.0.0b3

Download:
https://pear.php.net/manual/en/package.http.http-upload.php

Easy and secure managment of files submitted via HTML Forms.

pear install HTTP_Upload

This class provides an advanced file uploader system for file uploads made
from html forms. Features:
* Can handle from one file to multiple files.
* Safe file copying from tmp dir.
* Easy detecting mechanism of valid upload, missing upload or error.
* Gives extensive information about the uploaded file.
* Rename uploaded files in different ways: as it is, safe or unique
* Validate allowed file extensions
* Multiple languages error messages support (es, en, de, fr, it, nl, pt_BR)


Vulnerability Type:
======================
Arbitrary File Upload



CVE Reference:
==============
N/A



Vulnerability Details:
=====================

The package comes with an "upload_example.php" file to test the package, when uploading a "restricted" PHP file
user will get message like "Unauthorized file transmission".

Line: 488 of "Upload.php"
var $_extensionsCheck = array('php', 'phtm', 'phtml', 'php3', 'inc');

If user does not go thru the "Upload.php" code line by line. They will find option to set case sensitive check.
e.g. Line: 503 "$_extensionsCaseSensitive"=true

Line: 874

* @param bool $case_sensitive whether extension check is case sensitive.

* When it is case insensitive, the extension

* is lowercased before compared to the array

* of valid extensions.


This setting looks to prevent mixed or uppercase extension on disallowed PHP file type bypass before uploading.

However, some developers are unaware that "Apache" can process file with extension like PHP.1, PHP.; etc.
if the last extension is not specified in the list of mime-types known to the web server.

Therefore, attackers can easily bypass the security check by appending ".1" to end of the file,
which can result in arbitrary command execution on the affected server.

e.g.

"ext_bypass.php.1" contents:

<?php

echo passthru('cat /etc/passwd');

?>


Sucessfully Tested on: Bitnami wampstack-5.6.29-0.
Server version: Apache/2.4.23 (Win64)

Sucessfully Tested on: XAMPP for Linux 5.6.8-0
Server version: Apache/2.4.12 (Unix)

#  0day.today [2018-03-31]  #