CVE-2002-1824 in Internet Explorer
Summary
by MITRE
Microsoft Internet Explorer 6.0, when handling an expired CA-CERT in a webserver s certificate chain during a SSL/TLS handshake, does not prompt the user before searching for and finding a newer certificate, which may allow attackers to perform a man-in-the-middle attack. NOTE: it is not clear whether this poses a vulnerability.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 07/04/2024
The vulnerability described in CVE-2002-1824 relates to a security flaw in Microsoft Internet Explorer 6.0 that occurs during SSL/TLS certificate validation processes. This issue specifically manifests when a web server presents a certificate chain containing an expired CA-CERT certificate from the CA-CERT certification authority. The flaw stems from the browser's handling of certificate validation logic during secure connections, where the software automatically attempts to locate and substitute a valid certificate without user intervention or explicit notification. This behavior creates a potential security risk because the automatic certificate replacement process bypasses normal user awareness mechanisms that would typically alert users to certificate validation issues. The vulnerability operates at the application layer of the network stack, specifically within the SSL/TLS client implementation of Internet Explorer, and represents a deviation from standard certificate validation procedures that should require user confirmation before proceeding with certificate substitution.
The technical implementation of this vulnerability involves the browser's certificate chain validation algorithm failing to properly handle expired certificate authorities within the trust hierarchy. When Internet Explorer encounters an expired CA-CERT certificate in the server's certificate chain, it automatically initiates a search process to locate a valid certificate that can complete the trust chain. This automatic behavior violates standard security protocols where user consent should be required before accepting alternative certificates, particularly when dealing with certificate authority expiration. The flaw essentially allows the browser to perform certificate resolution without informing the user, creating a window where attackers could potentially exploit this automatic behavior to substitute malicious certificates for legitimate ones. This represents a weakness in the certificate validation process that could be leveraged by adversaries to establish fraudulent secure connections without user knowledge or consent.
The operational impact of this vulnerability extends beyond simple certificate validation issues and could enable sophisticated man-in-the-middle attacks against unsuspecting users. Attackers could potentially manipulate the certificate chain presented by a web server to trigger the automatic certificate replacement behavior, allowing them to intercept and modify secure communications between users and web services. The vulnerability's potential exploitation requires an attacker to have control over network traffic or server configuration to present a certificate chain that includes an expired CA-CERT certificate, but once triggered, it could allow for transparent interception of encrypted communications. This risk is particularly concerning given that Internet Explorer 6.0 was widely deployed in 2002, meaning a large user base could potentially be affected by this automatic certificate resolution behavior that bypasses normal security warnings. The vulnerability's classification as potentially non-vulnerable in the original description suggests that the actual exploitability may be limited, but the design flaw in the certificate handling process still represents a significant security concern.
The security implications of this vulnerability align with several established security frameworks and threat models. From a CWE perspective, this issue relates to weakness categories involving certificate validation and trust management, specifically CWE-295 for improper certificate validation and CWE-310 for cryptographic weaknesses. The vulnerability also maps to ATT&CK techniques involving credential access through man-in-the-middle attacks and session hijacking. The automatic certificate resolution behavior violates fundamental security principles of user awareness and explicit consent in cryptographic operations. Organizations using Internet Explorer 6.0 at the time would have been exposed to potential risks if they encountered web servers that presented certificate chains with expired CA-CERT certificates, as the browser's automatic behavior could facilitate transparent attack scenarios. This vulnerability highlights the importance of proper certificate validation procedures and the need for explicit user notification when certificate substitution occurs during secure connection establishment.
Mitigation strategies for this vulnerability should focus on both immediate browser configuration changes and broader security policy implementations. Users should be advised to avoid visiting websites that present certificate chains containing expired certificates, particularly those from CA-CERT or similar authorities. Network administrators should consider implementing certificate pinning policies and monitoring for unusual certificate validation behaviors. The recommended approach involves updating to newer versions of Internet Explorer that have improved certificate validation procedures, as well as implementing additional security layers such as intrusion detection systems that can monitor for certificate substitution attempts. Organizations should also consider deploying certificate monitoring tools that can alert administrators to certificate expiration events or unusual certificate chain validation patterns. The vulnerability's resolution ultimately required browser vendors to implement more robust certificate validation procedures that require explicit user consent before automatic certificate substitution occurs, aligning with industry best practices for secure certificate handling and preventing unauthorized certificate replacement during SSL/TLS handshakes.