CVE-2005-4871 in DB2
Summary
by MITRE
Certain XML functions in IBM DB2 8.1 run with the privileges of DB2 instead of the logged-in user, which allows remote attackers to create or overwrite files via (1) XMLFileFromVarchar or (2) XMLFileFromClob, or read files via (3) XMLVarcharFromFile or (4) XMLClobFromFile.
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Analysis
by VulDB Data Team • 08/02/2019
This vulnerability in IBM DB2 8.1 represents a critical privilege escalation and arbitrary file access flaw that fundamentally undermines the database's security model. The vulnerability stems from XML functions that execute with elevated privileges rather than the context of the logged-in user, creating a significant attack surface for remote adversaries. The affected functions include XMLFileFromVarchar, XMLFileFromClob, XMLVarcharFromFile, and XMLClobFromFile, which collectively enable attackers to manipulate the file system through database operations.
The technical implementation of this vulnerability leverages the inherent design flaw where XML processing functions in DB2 8.1 operate under the database service account privileges rather than the user context that initiated the database connection. This misalignment creates a privilege escalation path where remote attackers can execute arbitrary file system operations without proper authentication or authorization. The vulnerability is particularly dangerous because it allows for both file creation and reading operations, providing attackers with complete control over the file system accessible to the database service account.
From an operational impact perspective, this vulnerability enables attackers to perform a wide range of malicious activities including creating malicious files, overwriting critical system files, reading sensitive data from the file system, and potentially escalating privileges to gain broader system access. The remote nature of the attack means that adversaries can exploit this vulnerability from outside the network perimeter without requiring local system access. This makes the vulnerability particularly attractive to attackers as it provides a straightforward path to system compromise through database interfaces.
The vulnerability aligns with CWE-276, which describes improper privileges, and represents a classic case of privilege escalation through insecure function calls. From an ATT&CK framework perspective, this vulnerability maps to T1059 (Command and Scripting Interpreter) and T1078 (Valid Accounts) as attackers can leverage database accounts to execute commands and maintain persistence. The attack surface is further expanded by the fact that these XML functions are typically enabled by default in DB2 installations, making the vulnerability accessible without requiring additional configuration changes.
Mitigation strategies should focus on immediate patching of the IBM DB2 8.1 installation with the vendor-provided security updates. Organizations should also implement network segmentation to limit database access to trusted networks and apply the principle of least privilege to database accounts. Additional protective measures include disabling unnecessary XML functions, monitoring database activity for suspicious file operations, and implementing database activity monitoring tools to detect unauthorized file system access patterns. The vulnerability demonstrates the critical importance of proper privilege management in database systems and the potential consequences of insecure function implementations that bypass normal access controls.