1. Introduction
The CC GuestBook cc_guestbook.pl Multiple Parameter XSS vulnerability is a flaw in a Perl-based guestbook application that allows attackers to inject malicious scripts into web pages viewed by other users. This can lead to cookie theft and potentially compromise user accounts. The remote web server containing this script is affected, posing a Medium severity risk to confidentiality, integrity, and availability.
2. Technical Explanation
The cc_guestbook.pl CGI script does not properly sanitize user input, allowing an attacker to inject arbitrary JavaScript code. This cross-site scripting (XSS) attack can be exploited remotely by crafting a malicious URL or form submission that includes the harmful script. The vulnerability is tracked as CVE-2003-1556 and has a CWE designation of 79 (Improper Neutralization of Input During Web Page Generation). An attacker could, for example, inject JavaScript code to redirect users to a phishing site or steal their session cookies.
- Root cause: Missing input validation in the cc_guestbook.pl script allows arbitrary HTML and JavaScript to be included in web pages.
- Exploit mechanism: An attacker crafts a URL containing malicious JavaScript code within a guestbook entry parameter. When another user views that entry, the injected script executes in their browser. Example payload:
http://example.com/cc_guestbook.pl?name= - Scope: Affected systems are those running vulnerable versions of cc_guestbook.pl.
3. Detection and Assessment
Confirming vulnerability involves checking for the presence of the script and testing its input handling.
- Quick checks: Use
ls -l /path/to/cc_guestbook.plto verify the file exists. - Scanning: Nessus plugin ID 30849 may detect this vulnerability. This is an example only, and results should be verified.
- Logs and evidence: Examine web server logs for suspicious requests containing HTML tags or JavaScript code in guestbook entry parameters. Look for patterns like `