CVE-2014-3569 in MySQL Server
Summary
by MITRE
The ssl23_get_client_hello function in s23_srvr.c in OpenSSL 0.9.8zc, 1.0.0o, and 1.0.1j does not properly handle attempts to use unsupported protocols, which allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via an unexpected handshake, as demonstrated by an SSLv3 handshake to a no-ssl3 application with certain error handling. NOTE: this issue became relevant after the CVE-2014-3568 fix.
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Analysis
by VulDB Data Team • 05/07/2022
The vulnerability described in CVE-2014-3569 represents a critical denial of service flaw within OpenSSL implementations that affects versions 0.9.8zc, 1.0.0o, and 1.0.1j. This issue specifically targets the ssl23_get_client_hello function located in the s23_srvr.c file, which serves as a crucial component in the SSL/TLS handshake process. The vulnerability manifests when the function fails to properly handle attempts to use unsupported protocols, creating a scenario where remote attackers can exploit this weakness to crash the targeted daemon. The flaw becomes particularly significant in the context of applications that have explicitly disabled SSLv3 functionality, as the error handling mechanisms in place are insufficient to process unexpected handshake attempts. This vulnerability was notably triggered by the CVE-2014-3568 fix, which introduced new code paths that inadvertently exposed the null pointer dereference issue. The technical nature of this flaw aligns with CWE-476, which describes NULL pointer dereference conditions that can lead to application crashes and system instability.
The operational impact of CVE-2014-3569 extends beyond simple service disruption, as it enables remote attackers to systematically crash OpenSSL-based services through carefully crafted malicious handshake attempts. When an SSLv3 handshake is sent to a server application that has explicitly disabled SSLv3 support, the ssl23_get_client_hello function fails to properly validate the incoming handshake data, resulting in a NULL pointer dereference that ultimately causes the daemon to crash. This type of attack can be executed without authentication and requires minimal resources from the attacker, making it particularly dangerous for high-availability systems. The vulnerability affects a wide range of applications that rely on OpenSSL for secure communications, including web servers, email servers, and other network services that implement SSL/TLS protocols. The issue demonstrates a classic example of improper error handling in cryptographic libraries, where the fix for one vulnerability inadvertently introduces another that can be exploited for denial of service attacks.
From a cybersecurity perspective, this vulnerability aligns with several ATT&CK tactics including TA0043 (Reconnaissance) and TA0045 (Initial Access), as attackers can identify vulnerable systems and exploit them to disrupt services. The attack vector requires minimal sophistication, making it accessible to threat actors of varying skill levels. Organizations running affected OpenSSL versions face significant operational risks, as the vulnerability can be exploited to cause widespread service outages across multiple systems simultaneously. The timing of this vulnerability's relevance, following the CVE-2014-3568 fix, indicates that security patches may introduce new attack surfaces that were not previously apparent. This particular flaw represents a failure in input validation and error handling within the SSL/TLS protocol implementation, where the software does not adequately sanitize or validate handshake parameters before processing them. The vulnerability essentially creates a condition where the application's error handling logic becomes a point of failure rather than a protective mechanism, demonstrating the critical importance of thorough testing when implementing security fixes.
Organizations should prioritize immediate remediation by upgrading to OpenSSL versions that contain the appropriate patches for this vulnerability. The recommended mitigation strategy involves updating to OpenSSL 1.0.1k or later for the 1.0.1 series, or 1.0.0p or later for the 1.0.0 series, which contain the necessary fixes to properly handle unsupported protocol attempts. System administrators should also implement network-level monitoring to detect and potentially block suspicious handshake patterns that could indicate exploitation attempts. Additionally, organizations should consider implementing redundant systems and failover mechanisms to minimize the impact of potential service disruptions caused by this vulnerability. The incident underscores the importance of comprehensive security testing, particularly when addressing one vulnerability that may inadvertently expose others within complex cryptographic implementations. Security teams should conduct thorough vulnerability assessments of their OpenSSL implementations and ensure that all systems are updated with the latest security patches to prevent exploitation of this and similar vulnerabilities.