netVigilance Security Advisory #10

dt_guestbook version 1.0f XSS vulnerability 

Description:
dt_guestbook is a fully-featured message board system with admin interface. Due to program flaws it is possible for the remote attacker to conduct XSS attacks.
The remote attacker can convince the victim to open a specially crafted link that is a trusted guestbook server and execute arbitrary code in the user’s browser session.

External References: 
Mitre CVE: CVE-2006-6487 http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-6487 
NVD NIST: CVE-2006-6487 http://nvd.nist.gov/nvd.cfm?cvename=CVE-2006-6487
OSVDB: 30787 http://www.osvdb.com/displayvuln.php?osvdb_id=30787

Summary: 
dt_guestbook a fully-featured message board system with admin interface. 
A security problem in the product allows attackers to conduct XSS attacks. 
This vulnerability can be exploited only when PHP register_globals is On.

Release Date:
 

Severity:
Risk: Medium
 
CVSS Metrics
Access Vector: Remote
Access Complexity: High
Authentication: not-required
Confidentiality Impact: Partial
Integrity Impact: Partial
Availability Impact: Partial
Impact Bias: Normal
CVSS Base Score: 5.6
 
Target Distribution on Internet: Low
 
Exploitability: Functional Exploit
Remediation Level: Workaround
Report Confidence: Uncorroborated
 
Vulnerability Impact: Attack
Host Impact: cross-site scripting.


SecureScout Testcase ID:
TC 17940


Vulnerable Systems:
dt_guestbook 1.0f.

Vulnerability Type:
XSS (Cross-Site Scripting) to force a web-site to display malicious contents to the target, by sending a specially crafted request to the web-site. The vulnerable web-site is not the target of attack but is used as a tool for the hacker in the attack of the victim.

Vendor Status: Author Alexander Fedorov was notified on Dec 8 2006 and agreed to correct the XSS in his product. He has failed to respond to emails or Chat since Dec 8 2006.
.
Solution: Patch Possibly Pending from Vendor, please check http://fedorov.vitalain.ru for updates.
.
Workaround:
Set PHP register_globals to Off.
Example: 
HTTP REQUEST http://[TARGET]/[dt_guestbook_v1-directory]/index.php?submit=1&error[]=%3Cscript%3Ealert(document.cookie)%3C/script%3E
REPLY
...
will execute <script>alert(document.cookie)</script>
... 

Advisory URL: http://www.netvigilance.com/advisory0009 

Credits: 
Jesper Jurcenoks
Co-founder netVigilance, Inc
www.netvigilance.com