CVE-2003-0981 in Visitorbook
Summary
by MITRE
FreeScripts VisitorBook LE (visitorbook.pl) logs the reverse DNS name of a visiting host, which allows remote attackers to spoof the origin of their incoming requests and facilitate cross-site scripting (XSS) attacks.
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Analysis
by VulDB Data Team • 06/17/2018
The vulnerability described in CVE-2003-0981 affects FreeScripts VisitorBook LE, a web-based visitor log application that processes and displays information about website visitors. This particular flaw stems from the application's logging mechanism that records reverse DNS names of incoming requests, creating a pathway for malicious actors to manipulate the displayed information and potentially execute cross-site scripting attacks. The vulnerability represents a classic case of trust exploitation where the application's reliance on reverse DNS resolution creates an attack surface that adversaries can leverage for deceptive purposes.
The technical implementation of this vulnerability involves the visitorbook.pl script performing reverse DNS lookups on connecting hosts and storing the resulting hostnames in its log database. When the application displays visitor information on web pages, it incorporates these reverse DNS names directly into the HTML output without proper sanitization or encoding. This creates a direct pathway for cross-site scripting attacks because attackers can manipulate their network environment to resolve to malicious hostnames that, when displayed, execute arbitrary JavaScript code in the browsers of other users viewing the visitor log. The flaw essentially transforms a legitimate logging function into a potential vector for code injection.
The operational impact of this vulnerability extends beyond simple information disclosure, as it enables attackers to craft malicious payloads that can compromise user sessions and execute unauthorized actions within the context of the vulnerable web application. When users view the visitor log pages, they are exposed to potentially malicious JavaScript code that could steal cookies, redirect them to phishing sites, or perform other malicious activities. This type of vulnerability falls under CWE-79, which specifically addresses cross-site scripting flaws in web applications, and aligns with ATT&CK technique T1059.007 for script injection attacks. The attack surface is particularly concerning because it operates at the application level where user trust is implicit in the visitor log functionality.
Mitigation strategies for this vulnerability should focus on implementing proper input validation and output sanitization for all data that originates from external sources, particularly network information like reverse DNS names. The application should employ HTML encoding or escaping mechanisms when displaying any data that might have originated from untrusted sources. Additionally, administrators should consider implementing network-level restrictions that prevent spoofing of DNS resolution responses, though this approach has limitations in modern distributed network environments. The most effective remediation involves removing or disabling the reverse DNS logging functionality entirely, or implementing a more secure method of displaying visitor information that does not directly incorporate potentially malicious hostnames. Organizations should also consider implementing content security policies to add an additional layer of protection against XSS attacks that might still occur through other vectors.