CVE-2017-6369 in Firebird
Summary
by MITRE
Insufficient checks in the UDF subsystem in Firebird 2.5.x before 2.5.7 and 3.0.x before 3.0.2 allow remote authenticated users to execute code by using a 'system' entrypoint from fbudf.so.
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Analysis
by VulDB Data Team • 10/09/2025
The vulnerability identified as CVE-2017-6369 represents a critical security flaw within the Universal Database (UDF) subsystem of Firebird database management systems. This issue affects versions 2.5.x prior to 2.5.7 and 3.0.x prior to 3.0.2, where insufficient validation mechanisms exist in the user-defined function framework. The vulnerability stems from the improper handling of system entrypoints within the fbudf.so library, which is a shared library containing user-defined functions for Firebird databases. Attackers with authenticated access to the database can exploit this weakness to execute arbitrary code on the target system, potentially leading to complete system compromise.
The technical root cause of this vulnerability lies in the inadequate input validation and privilege escalation mechanisms within the UDF subsystem. When authenticated users interact with the database and attempt to utilize specific system entrypoints from the fbudf.so library, the system fails to properly verify the legitimacy of these requests. This allows malicious actors to craft specially formatted UDF calls that bypass normal security boundaries and gain access to system-level functionality. The flaw specifically affects how the database engine processes and validates function calls that should be restricted to privileged operations, creating an avenue for unauthorized code execution.
The operational impact of CVE-2017-6369 extends beyond simple privilege escalation, as it enables attackers to execute arbitrary code with the privileges of the database service account. This typically means that successful exploitation could result in complete system compromise, data exfiltration, or the installation of persistent backdoors. The vulnerability is particularly dangerous because it requires only authenticated access to the database, which is often easier to obtain than gaining direct system access. Organizations running affected Firebird versions face significant risk, especially in environments where database credentials are widely distributed or where database administrators maintain elevated privileges.
Mitigation strategies for this vulnerability center around immediate patching of affected Firebird installations to versions 2.5.7 or 3.0.2 and later. System administrators should also implement network segmentation to limit database access to trusted hosts and enforce strict access controls through database authentication mechanisms. The vulnerability aligns with CWE-20, "Improper Input Validation," and can be mapped to ATT&CK technique T1059.007 for "Command and Scripting Interpreter: Python" or similar execution techniques. Additional protective measures include monitoring database access logs for unusual UDF usage patterns and implementing database activity monitoring solutions that can detect anomalous function call sequences. Organizations should also consider disabling unnecessary UDF functionality where possible and regularly auditing database user permissions to minimize potential attack surfaces.