CVE-2017-10788 in DBD::mysql Module
Summary
by MITRE
The DBD::mysql module through 4.043 for Perl allows remote attackers to cause a denial of service (use-after-free and application crash) or possibly have unspecified other impact by triggering (1) certain error responses from a MySQL server or (2) a loss of a network connection to a MySQL server. The use-after-free defect was introduced by relying on incorrect Oracle mysql_stmt_close documentation and code examples.
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Analysis
by VulDB Data Team • 12/09/2022
The DBD::mysql module vulnerability CVE-2017-10788 represents a critical security flaw in the Perl database connectivity library that interfaces with MySQL servers. This vulnerability affects versions through 4.043 and manifests through improper handling of database connection states, specifically when encountering error responses from MySQL servers or experiencing network connection losses. The flaw stems from the module's reliance on incorrect documentation and code examples provided by Oracle for the mysql_stmt_close function, creating a dangerous dependency that leads to memory corruption issues.
The technical implementation of this vulnerability involves a use-after-free condition that occurs when the DBD::mysql module attempts to clean up prepared statement resources inappropriately. When a MySQL server returns certain error responses or when network connectivity is lost during active database operations, the module's cleanup routines execute code that references memory locations that have already been freed. This improper memory management creates a scenario where the application can access invalid memory addresses, leading to application crashes or potentially more severe consequences depending on the execution context. The vulnerability specifically targets the mysql_stmt_close function calls within the module's connection handling code, where developers incorrectly assumed certain behaviors based on misleading Oracle documentation.
From an operational perspective, this vulnerability poses significant risks to applications that rely on Perl database connectivity with MySQL servers. The denial of service impact can disrupt business operations when applications crash due to memory corruption, while the potential for unspecified other impacts suggests the possibility of remote code execution or data corruption scenarios. Attackers can trigger this vulnerability through simple network-based attacks that force error conditions or connection drops, making it particularly dangerous in production environments where database connectivity is essential. The vulnerability affects any application using the affected DBD::mysql module version, including web applications, enterprise systems, and automated processes that depend on database operations.
The security implications of CVE-2017-10788 align with CWE-416, which addresses use-after-free vulnerabilities in software systems. This classification emphasizes the memory safety issue inherent in the module's design, where resource management fails to properly track object lifetimes. Additionally, the vulnerability demonstrates characteristics consistent with ATT&CK technique T1499.004, which involves network disruption attacks that can lead to denial of service conditions. Organizations should immediately update to patched versions of the DBD::mysql module, verify their application dependencies, and implement monitoring for potential exploitation attempts. The fix typically involves correcting the module's handling of prepared statement cleanup routines to properly account for connection state changes and error conditions. Security teams should also consider implementing network segmentation and access controls to limit potential attack vectors while awaiting patch deployment across all affected systems.