CVE-2018-7409 in unixODBC
Summary
by MITRE
In unixODBC before 2.3.5, there is a buffer overflow in the unicode_to_ansi_copy() function in DriverManager/__info.c.
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Analysis
by VulDB Data Team • 02/08/2023
The vulnerability identified as CVE-2018-7409 represents a critical buffer overflow flaw within the unixODBC library version 2.3.4 and earlier, specifically affecting the unicode_to_ansi_copy() function located in the DriverManager/__info.c source file. This issue arises from inadequate input validation and boundary checking when processing unicode character data during the conversion process to ansi encoding. The buffer overflow occurs when the function fails to properly validate the length of incoming unicode strings before copying them into fixed-size buffers, creating a potential exploitation vector for malicious actors. The vulnerability is particularly concerning as unixODBC serves as a fundamental component for database connectivity across multiple platforms and applications, making it a prime target for attackers seeking to compromise system integrity.
The technical implementation of this flaw stems from the function's handling of character set conversions without proper bounds checking mechanisms. When unicode strings are processed through the unicode_to_ansi_copy() function, the code does not adequately verify that the destination buffer can accommodate the converted ansi string, leading to memory corruption that can result in arbitrary code execution. This type of vulnerability falls under CWE-121, which categorizes buffer overflow conditions where insufficient boundary checks allow data to overwrite adjacent memory locations. The operational impact extends beyond simple memory corruption as the vulnerability can be exploited through maliciously crafted database connection strings or unicode data inputs that trigger the affected conversion function during normal database operations.
The exploitation of CVE-2018-7409 can lead to severe consequences including privilege escalation, system compromise, and denial of service conditions within applications that rely on unixODBC for database connectivity. Attackers can leverage this vulnerability by crafting specific unicode input that, when processed by the vulnerable function, causes the buffer overflow to overwrite critical memory segments. This aligns with ATT&CK technique T1059, where adversaries use command injection to execute malicious code through vulnerable input processing functions. The vulnerability affects a wide range of applications including web servers, database management systems, and enterprise applications that utilize unixODBC drivers, making the potential attack surface extensive. The flaw particularly impacts environments where database connectivity is handled through ODBC interfaces and where unicode data processing is prevalent.
Organizations should implement immediate mitigations including upgrading to unixODBC version 2.3.5 or later, which contains the necessary patches to address the buffer overflow vulnerability. Additionally, input validation measures should be strengthened at application layers that interface with database systems to prevent malicious unicode data from reaching the vulnerable function. Network segmentation and monitoring should be enhanced to detect unusual database connection patterns that might indicate exploitation attempts. The remediation process should include comprehensive testing of all applications utilizing unixODBC to ensure compatibility with the patched version while verifying that no regressions have been introduced. Security teams should also conduct thorough vulnerability assessments of their database environments to identify any potential exposure through other related components that might interact with the vulnerable ODBC functionality, ensuring that the entire database connectivity stack remains secure against similar exploitation vectors.