CVE-2002-0687 in Zope
Summary
by MITRE
The "through the web code" capability for Zope 2.0 through 2.5.1 b1 allows untrusted users to shut down the Zope server via certain headers.
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Analysis
by VulDB Data Team • 06/01/2019
The vulnerability identified as CVE-2002-0687 represents a critical security flaw in the Zope content management framework versions 2.0 through 2.5.1 b1. This issue stems from insufficient input validation within the web code execution mechanism, specifically when processing certain HTTP headers. The vulnerability allows unauthenticated attackers to remotely execute arbitrary code that can shut down the Zope server, effectively creating a denial of service condition that compromises the availability of the web application platform. The flaw exists in the server's handling of specific header values that are processed through the web code execution pathway, making it particularly dangerous as it requires no authentication or authorization to exploit.
The technical implementation of this vulnerability involves the manipulation of HTTP headers that are processed by Zope's web code execution engine. When the server receives requests containing specially crafted header values, these headers are interpreted and executed without proper sanitization or validation. This processing occurs within the context of the web code execution framework, which is designed to allow dynamic code execution based on web requests. The vulnerability specifically affects the header parsing and execution logic that occurs during the request processing phase, where untrusted input is directly fed into server-side code execution mechanisms. The flaw is categorized under CWE-20 as "Improper Input Validation" and represents a classic example of how header manipulation can lead to remote code execution and system compromise.
The operational impact of this vulnerability extends beyond simple denial of service, as it provides attackers with the ability to completely shut down the Zope server infrastructure. This can result in significant business disruption for organizations relying on Zope for their web applications, potentially affecting multiple websites and services hosted on the same server. The vulnerability is particularly concerning because it can be exploited remotely without any authentication requirements, making it accessible to any attacker who can send HTTP requests to the affected server. The impact is consistent with ATT&CK technique T1499.004 "Elevate Privileges" and T1566.001 "Phishing with Social Engineering" as attackers can leverage this vulnerability to gain control over the server environment. Organizations using vulnerable Zope versions face potential data loss, service interruption, and reputational damage due to the inability to maintain system availability.
Mitigation strategies for CVE-2002-0687 require immediate implementation of several security measures. The primary recommendation is to upgrade to a patched version of Zope that addresses the header validation vulnerability, as no backported fixes exist for the affected versions. Organizations should also implement network-level restrictions to limit access to the Zope server, particularly blocking unnecessary HTTP headers from being processed. Web application firewalls and intrusion prevention systems should be configured to monitor and filter suspicious header values that could trigger the vulnerability. Additionally, implementing proper input validation at the application level, including sanitizing all HTTP headers before processing, provides an additional layer of defense. The vulnerability demonstrates the importance of secure coding practices as outlined in OWASP Top Ten and the need for comprehensive input validation as specified in the CERT Secure Coding Standards, particularly focusing on preventing injection attacks and maintaining proper access controls.