CVE-2017-10789 in DBD::mysql Module
Summary
by MITRE
The DBD::mysql module through 4.043 for Perl uses the mysql_ssl=1 setting to mean that SSL is optional (even though this setting's documentation has a "your communication with the server will be encrypted" statement), which allows man-in-the-middle attackers to spoof servers via a cleartext-downgrade attack, a related issue to CVE-2015-3152.
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Analysis
by VulDB Data Team • 12/09/2022
The DBD::mysql module vulnerability CVE-2017-10789 represents a critical security flaw in Perl database connectivity that fundamentally misinterprets SSL configuration settings. This vulnerability affects versions through 4.043 and stems from the module's improper handling of the mysql_ssl=1 parameter, which documentation misleadingly suggests provides encrypted communication. The flaw creates a dangerous security boundary where the module treats SSL as optional rather than mandatory, leaving applications susceptible to sophisticated man-in-the-middle attacks that can downgrade secure connections to insecure cleartext communications. This misconfiguration creates a pathway for attackers to intercept and manipulate database traffic without detection, undermining the entire security posture of applications relying on this module for database connectivity.
The technical implementation of this vulnerability operates through a fundamental misunderstanding of SSL/TLS connection establishment protocols within the Perl database driver framework. When developers configure mysql_ssl=1, they expect mandatory encryption of database communications, but the module's implementation treats this as an optional feature that can be bypassed during connection negotiation. This behavior creates a downgrade attack vector where malicious actors can intercept the initial connection handshake and force the system to establish a cleartext connection instead of the intended encrypted one. The vulnerability's operational impact extends beyond simple data interception, as it enables attackers to perform sophisticated session hijacking and credential theft operations that can compromise entire database environments.
From an operational security perspective, this vulnerability directly violates industry standards such as CWE-310 and aligns with ATT&CK techniques for credential access and defense evasion. The flaw creates a persistent security risk that can be exploited across multiple attack vectors, including network reconnaissance and active exploitation phases. Organizations using Perl applications with database connectivity through DBD::mysql face significant exposure to data breaches, as the vulnerability allows attackers to establish unauthorized database access without proper authentication mechanisms. The security implications extend to compliance requirements such as pci dss and gdpr, where encryption of data in transit is mandatory for protecting sensitive information and maintaining regulatory compliance.
The recommended mitigation strategies for CVE-2017-10789 involve immediate version upgrades to DBD::mysql 4.044 or later, which properly implements SSL requirements as mandatory rather than optional. System administrators should conduct comprehensive vulnerability assessments to identify all applications using affected versions of the module, followed by thorough testing of patched implementations to ensure compatibility with existing database configurations. Additionally, organizations should implement network-level monitoring to detect potential downgrade attacks and establish robust certificate validation procedures that can identify and prevent unauthorized certificate substitutions. Security teams should also consider implementing additional layers of protection such as database firewalls and network segmentation to limit the potential impact of successful exploitation attempts, while maintaining detailed audit logs of all database connection attempts for forensic analysis purposes.