AWStats Remote Command Execution Vulnerability

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AWStats Remote Command Execution Vulnerability

iDEFENSE Security Advisory 01.17.05
http://www.idefense.com/application/...ulnerabilities January 17, 2005


I. BACKGROUND

AWStats is a free tool that generates advanced web, ftp or mail server statistics, graphically. More information about AWStats is available from:

http://awstats.sourceforge.net

II. DESCRIPTION

Remote exploitation of an input validation vulnerability in AWStats allows attackers to execute arbitrary commands under the privileges of the web server.

The problem specifically exists when the application is running as a CGI script on a web server. The "configdir" parameter contains
unfiltered user-supplied data that is utilized in a call to the Perl routine open() as can be seen here on line 1082 of awstats.pl:

if (open(CONFIG,"$searchdir$PROG.$SiteConfig.conf"))

The "searchdir" variables hold the value of the parameter provided by the attacker from "configdir." An attacker can cause arbitrary commands to be executed by prefixing them with the "|" character.

III. ANALYSIS

Successful exploitation allows remote attackers to execute arbitrary commands under the privileges of the web server. This can lead to
further compromise as it provides remote attackers with local access.

IV. DETECTION

iDEFENSE has confirmed that AWStats version 6.1 is vulnerable.
It is suspected that earlier versions are also vulnerable.

V. WORKAROUND

Add a filter around the "configdir" parameter by replacing the following line:

if ($QueryString =~ /configdir=([^&]+)/i)
{
$DirConfig=&DecodeEncodedString("$1");
}

With:

if ($QueryString =~ /configdir=([^&]+)/i)
{
$DirConfig=&DecodeEncodedString("$1");
$DirConfig=~tr/a-z0-9_\-\/\./a-z0-9_\-\/\./cd;
}

VI. VENDOR RESPONSE

This vulnerability is addressed in AWStats 6.3, available for download at:

http://awstats.sourceforge.net/#DOWNLOAD

VII. CVE INFORMATION

A Mitre Corp. Common Vulnerabilities and Exposures (CVE) number has not been assigned yet.

VIII. DISCLOSURE TIMELINE

10/21/2004 Initial vendor notification
01/02/2005 Initial vendor response
01/17/2005 Public disclosure

IX. CREDIT

The discoverer of this vulnerability wishes to remain anonymous.

Get paid for vulnerability research
http://www.idefense.com/poi/teams/vcp.jsp

 

 

 

 

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