CVE-2004-0112 in OpenSSL
Summary
by MITRE
The SSL/TLS handshaking code in OpenSSL 0.9.7a, 0.9.7b, and 0.9.7c, when using Kerberos ciphersuites, does not properly check the length of Kerberos tickets during a handshake, which allows remote attackers to cause a denial of service (crash) via a crafted SSL/TLS handshake that causes an out-of-bounds read.
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Analysis
by VulDB Data Team • 01/22/2025
The vulnerability described in CVE-2004-0112 represents a critical flaw in the OpenSSL cryptographic library that affects versions 0.9.7a through 0.9.7c. This issue specifically targets the SSL/TLS handshaking process when Kerberos ciphersuites are employed, creating a scenario where remote attackers can exploit a buffer over-read condition. The vulnerability stems from inadequate input validation within the Kerberos ticket processing logic during SSL/TLS negotiation phases, fundamentally compromising the stability of systems relying on these cryptographic implementations.
The technical implementation of this flaw occurs during the SSL/TLS handshake when Kerberos authentication is negotiated between client and server components. When OpenSSL processes Kerberos tickets, it fails to validate the length of incoming ticket data before attempting to read from memory locations that correspond to the ticket size. This improper validation leads to an out-of-bounds memory read operation that can cause the application to crash or behave unpredictably. The vulnerability is classified as a buffer overflow condition under CWE-129, specifically manifesting as an insufficient input validation issue that allows attackers to manipulate memory access patterns through crafted handshake messages.
The operational impact of this vulnerability extends beyond simple service disruption to potentially enable more sophisticated attack vectors. Remote attackers can leverage this weakness to perform denial of service attacks against SSL/TLS services that utilize Kerberos authentication, effectively rendering the targeted systems unavailable to legitimate users. The vulnerability affects any system running affected OpenSSL versions when Kerberos ciphersuites are enabled, making it particularly dangerous for enterprise environments that depend on secure authentication mechanisms. Organizations utilizing Kerberos-based authentication for SSL/TLS connections face significant risk exposure, as this flaw can be exploited without requiring authentication credentials or specialized privileges.
Mitigation strategies for CVE-2004-0112 primarily involve immediate patching of affected OpenSSL installations to versions that address the buffer validation issue. System administrators should prioritize updating their OpenSSL implementations to versions that have corrected the Kerberos ticket length checking mechanism. Additionally, organizations can implement temporary workarounds such as disabling Kerberos ciphersuites in SSL/TLS configurations until proper patches are deployed. Network monitoring solutions should be configured to detect unusual handshake patterns that might indicate exploitation attempts, while firewall rules can be adjusted to restrict access to SSL/TLS services when Kerberos authentication is not required. This vulnerability aligns with ATT&CK technique T1499.004 for denial of service attacks and represents a classic example of how improper input validation can create exploitable conditions in cryptographic implementations.
The broader implications of this vulnerability highlight the critical importance of proper memory management and input validation in security-critical software components. The flaw demonstrates how seemingly isolated issues in cryptographic libraries can have widespread consequences across network infrastructure, particularly when authentication mechanisms are involved. Organizations should maintain comprehensive patch management procedures and regularly audit their cryptographic implementations to identify similar validation weaknesses. The vulnerability serves as a reminder that even minor oversights in security code can create significant attack surfaces, emphasizing the need for thorough code review processes and adherence to security best practices throughout the software development lifecycle.