Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection')
By design, the JDBCAppender in Log4j 1.2.x accepts an SQL statement as a configuration parameter where the values to be inserted are converters from PatternLayout. The message converter, %m, is likely to always be included. This allows attackers to manipulate the SQL by entering crafted strings into input fields or headers of an application that are logged allowing unintended SQL queries to be executed. Note this issue only affects Log4j 1.x when specifically configured to use the JDBCAppender, which is not the default. Beginning in version 2.0-beta8, the JDBCAppender was re-introduced with proper support for parameterized SQL queries and further customization over the columns written to in logs. Apache Log4j 1.2 reached end of life in August 2015. Users should upgrade to Log4j 2 as it addresses numerous other issues from the previous versions.
CWE-89 - SQL Injection
Structured Query Language (SQL) injection attacks are one of the most common types of vulnerabilities. They exploit weaknesses in vulnerable applications to gain unauthorized access to backend databases. This often occurs when an attacker enters unexpected SQL syntax in an input field. The resulting SQL statement behaves in the background in an unintended manner, which allows the possibility of unauthorized data retrieval, data modification, execution of database administration operations, and execution of commands on the operating system.