CVE-2012-4857 in Informix Dynamic Server
Summary
by MITRE
Buffer overflow in IBM Informix 11.50 through 11.50.xC9W2 and 11.70 before 11.70.xC7 allows remote authenticated users to execute arbitrary code via a crafted SQL statement.
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Analysis
by VulDB Data Team • 12/20/2021
The vulnerability identified as CVE-2012-4857 represents a critical buffer overflow flaw within IBM Informix database management systems affecting versions 11.50 through 11.50.xC9W2 and 11.70 before 11.70.xC7. This security weakness stems from inadequate input validation mechanisms within the database engine's processing of SQL statements, creating an exploitable condition that can be leveraged by authenticated remote attackers to achieve arbitrary code execution. The vulnerability resides in the database server's handling of malformed SQL constructs that exceed predetermined buffer boundaries, potentially allowing malicious actors to overwrite adjacent memory locations with crafted payload data.
The technical implementation of this buffer overflow occurs during the parsing and execution phases of SQL statement processing within the Informix database engine. When an authenticated user submits a specially crafted SQL query containing oversized data elements or malformed parameters, the system fails to properly validate input lengths against allocated buffer sizes. This validation failure enables attackers to overflow the designated memory buffers and overwrite critical program execution data including return addresses, function pointers, or other control structures. The vulnerability specifically affects the database server's SQL processing routines and can be triggered through various SQL constructs such as large string literals, complex nested queries, or improperly formatted parameter bindings.
From an operational perspective, this vulnerability presents a severe risk to organizations relying on IBM Informix databases, as it allows authenticated remote attackers to execute arbitrary code with the privileges of the database service account. The impact extends beyond simple data compromise to potentially enable full system takeover, data exfiltration, and lateral movement within network environments. Attackers can leverage this vulnerability to establish persistent backdoors, escalate privileges, or deploy additional malicious payloads without requiring physical access to the database server. The authenticated requirement reduces the attack surface compared to unauthenticated exploits, but still represents a significant threat vector for organizations with compromised user credentials or insider threats.
Organizations should implement immediate mitigations including applying the relevant IBM security patches and updates released to address this vulnerability. System administrators must ensure that all affected Informix database instances are updated to versions containing the necessary fixes. Network segmentation and access controls should be strengthened to limit the attack surface, while monitoring systems should be configured to detect unusual SQL query patterns that might indicate exploitation attempts. The vulnerability aligns with CWE-121, which describes buffer overflow conditions where insufficient boundary checks allow data to be written beyond allocated buffer space. This weakness maps to attack techniques in the MITRE ATT&CK framework under the T1059.008 sub-technique for command and scripting interpreter, as successful exploitation would enable attackers to execute arbitrary commands through the database interface. Additionally, the vulnerability demonstrates characteristics of T1566, which covers credential access through exploitation of database systems, making it particularly dangerous in environments where database administrators have elevated privileges.