PhpWiki fails to properly restrict uploaded files

Overview

PhpWiki fails to properly restrict uploaded files, which can allow a remote attacker to execute arbitrary commands on a vulnerable system.

Description

PhpWiki is Wiki software that is implemented in PHP. PhpWiki includes an “UpLoad” feature that allows users to upload files. Files with a .php extension are not permitted, however other extensions are allowed. This can allow an attacker to upload a file that can be processed by PHP on the PhpWiki server.

Note that this vulnerability is being actively exploited.

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Impact

A remote attacker may be able to execute arbitrary PHP code on a vulnerable server. This can allow arbitrary command execution on the system.

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Solution

We are currently unaware of a practical solution to this problem.

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Disallow uploads

PhpWiki can be configured to disallow uploads by moving or removing lib/plugin/UpLoad.php.

Restrict uploads of PHP files

This vulnerability can be mitigated by restricting the ability to upload PHP files. This can be accomplished by adding the following lines to the list of disallowed extensions:
.php
.phtml
.php3
.php4
.php5
Note that this list may not be exhaustive. Other web server and PHP configurations may allow other file extensions to be processed by PHP.

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Vendor Information

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CVSS Metrics

Group	Score	Vector
Base
Temporal
Environmental

References

• <http://www.nabble.com/Important-UpLoad-security-fix!-was--Fwd:--phpwiki---Open-Discussion--RE:-upload-security-risk--t3543463.html&gt;
• <http://secunia.com/advisories/24888/&gt;

Acknowledgements

Thanks to Reini Urban for reporting this vulnerability.

This document was written by Will Dormann.

Other Information

CVE IDs:	CVE-2007-2024
Severity Metric:	18.42 Date Public: