Netscape Communicator Cross-Site Scripting via Character Conversion
Severe, but no confirmed exploitation yet. Schedule remediation in your next patch cycle and apply mitigations if you're exposed.
An unauthenticated attacker, remotely over the network, can cause limited impact to confidentiality and integrity and availability.
Netscape Communicator 4.04 through 4.7 (and possibly other versions) in various UNIX operating systems converts the 0x8b character to a "<" sign, and the 0x9b character to a ">" sign, which could allow remote attackers to attack other clients via cross-site scripting (CSS) in CGI programs that do not filter these characters.
Inferred from the weakness type (CWE) and how the flaw is reached — the techniques an attacker would chain to exploit this. Real-world corroboration appears here as threat intel is folded in.
Generated by Wavense from the CVE record — an immediate mitigation and the permanent fix.
As an interim measure, deploy a Web Application Firewall (WAF) to filter and encode potentially malicious input before it reaches vulnerable CGI applications. Implement network-level intrusion detection systems (IDS) to monitor for known XSS attack patterns targeting clients. Train users to be cautious of suspicious links and emails that could exploit browser vulnerabilities.
The permanent resolution is to upgrade Netscape Communicator clients from versions 4.04 through 4.7 (and potentially other affected versions) to a patched or later release that correctly handles character encoding. Furthermore, all web applications, especially CGI programs, must implement strict input validation and output encoding for all user-supplied data to prevent Cross-Site Scripting vulnerabilities.
An attacker can inject malicious scripts into web pages by exploiting Netscape Communicator's incorrect character conversion of 0x8b to '<' and 0x9b to '>'. This allows for client-side attacks like session hijacking, credential theft, or defacement within the user's browser context, severely compromising user data and system integrity.
No CWE classification has been assigned.
Other CVEs affecting communicator
Netscape Communicator before 4.77 allows remote attackers to execute arbitrary Javascript via a GIF image whose comment contains the Javascript.
Buffer overflow in the HTML parser for Netscape 4.75 and earlier allows remote attackers to execute arbitrary commands via a long password value in a form field.
Netscape Communicator does not properly prevent a ServerSocket object from being created by untrusted entities, which allows remote attackers to create a server on the victim's system via a malicious applet, as demonstrated by Brown Orifice.
Buffer overflow in Netscape Navigator/Communicator 4.7 for Windows 95 and Windows 98 allows remote attackers to cause a denial of service, and possibly execute arbitrary commands, via a long argument after the ? character in a URL that references an .asp, .cgi, .html, or .pl file.
The byte code verifier component of the Java Virtual Machine (JVM) allows remote execution through malicious web pages.
A configuration in a web browser such as Internet Explorer or Netscape Navigator allows execution of active content such as ActiveX, Java, Javascript, etc.