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CERT Coordination Center

A1Stats multiple CGI scripts fail to adequately validate user input

Vulnerability Note VU#471691

Original Release Date: 2002-09-26 | Last Revised: 2003-02-24


A1Stats does not properly validate user input, allowing directory traversal and overwriting of files.


A1Stats is a CGI script that provides reports on web site traffic. A1Stats does not properly filter the CGI query string. An attacker may exploit this vulnerability to traverse directories on the web server or to overwrite arbitrary files to which the web server process has write access.


Remote attackers can read or write any file on the server, with privileges of the web server process.



Upgrade to version 1.6 or later of A1Stats:

Vendor Information

Affected   Unknown   Unaffected

Drummond Miles

Notified:  September 24, 2002 Updated:  September 26, 2002



Vendor Statement

Yes, I can confirm that this vulnerability did exist. It was fixed in version 1.6 which was released in April, 2001. You can get the current version (1.8) at

Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.


The CERT/CC has no additional comments at this time.

If you have feedback, comments, or additional information about this vulnerability, please send us email.

CVSS Metrics

Group Score Vector
Base N/A N/A
Temporal N/A N/A
Environmental N/A



Thanks to neme for reporting this vulnerability.

This document was written by Shawn Van Ittersum.

Other Information

CVE IDs: CVE-2001-0561
Severity Metric: 0.78
Date Public: 2001-05-07
Date First Published: 2002-09-26
Date Last Updated: 2003-02-24 20:20 UTC
Document Revision: 10

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