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Mitigation Strategies Analysis for mybatis/mybatis-3

Mitigation Strategy: Parameterized Queries (Prefer over ${})

  • Mitigation Strategy: #{} Parameterized Queries (Prefer over ${})

    • Description:

      1. Identify all SQL statements: Examine all MyBatis mapper XML files (.xml). Locate all <select>, <insert>, <update>, and <delete> tags.
      2. Analyze dynamic SQL: Within each SQL statement, identify any parts that are dynamically generated based on input (e.g., WHERE clauses, ORDER BY clauses, table names, column names).
      3. Replace ${} with #{}: Wherever possible, replace direct string substitution (${}) with parameterized queries (#{}). #{} tells MyBatis to treat the value as a parameter, which will be properly escaped by the underlying JDBC driver.
      4. Use <bind> for complex expressions: If you need to perform string concatenation or other operations before passing the value to the query, use the <bind> element to create a new variable within the MyBatis context. This keeps the logic within MyBatis and allows it to handle escaping. Example: 
        <select id="findUsersByName" resultType="User">
  <bind name="pattern" value="'%' + _parameter + '%'" />
  SELECT * FROM users WHERE username LIKE #{pattern}
</select>
      5. Test thoroughly: After making changes, thoroughly test the application to ensure that the queries still function correctly and that no SQL injection vulnerabilities are present. Use a variety of inputs, including potentially malicious ones.

    • Threats Mitigated:

      • SQL Injection (Severity: Critical): Direct string substitution (${}) allows attackers to inject arbitrary SQL code, potentially leading to data breaches, data modification, or even complete system compromise. #{} prevents this by treating input as data, not code.
      • Second-Order SQL Injection (Severity: Critical): Even if data is initially sanitized, if it's later used in a dynamic SQL statement with ${}, it could still be vulnerable. #{} mitigates this risk.

    • Impact:

      • SQL Injection: Risk reduction: Very High (near elimination if used consistently). #{} is the primary defense against SQL injection in MyBatis.
      • Second-Order SQL Injection: Risk reduction: Very High.

    • Currently Implemented:

      • Mapper XML files: userMapper.xml, productMapper.xml (mostly implemented, some ${} usage remains in orderMapper.xml).
      • Java code interacting with mappers: Generally uses parameterized methods.

    • Missing Implementation:

      • orderMapper.xml: Contains several instances of ${} for dynamic ORDER BY clauses. These need to be refactored to use #{} or a safe alternative (see below).
      • Dynamic table name selection in reportService.java: Currently uses string concatenation to build the table name. This needs to be addressed (see "Dynamic Table/Column Names" mitigation below).

Mitigation Strategy: Safe Dynamic ORDER BY and LIMIT (MyBatis-Specific Handling)

  • Mitigation Strategy: Safe Dynamic ORDER BY and LIMIT (MyBatis-Specific Handling)

    • Description:

      1. Identify ORDER BY and LIMIT clauses: Locate all dynamic ORDER BY and LIMIT clauses in your mapper XML files.
      2. Whitelist approach (for ORDER BY within MyBatis): While the safest approach involves whitelisting in your Java service layer before calling MyBatis, you can implement a limited form of whitelisting within the MyBatis XML using <choose>, <when>, and <otherwise>: 
        <select id="findUsers" resultType="User">
  SELECT * FROM users
  ORDER BY
  <choose>
    <when test="orderBy == 'username'">username</when>
    <when test="orderBy == 'creation_date'">creation_date</when>
    <otherwise>id</otherwise> <!-- Default sort column -->
  </choose>
  <if test="orderDirection != null">
    <choose>
      <when test="orderDirection == 'ASC'">ASC</when>
      <when test="orderDirection == 'DESC'">DESC</when>
      <otherwise>ASC</otherwise>
    </choose>
  </if>
</select>
        This approach is less flexible than a Java-side whitelist but is far safer than using ${} directly with user input. The orderBy and orderDirection variables would still be passed in from Java, but their values are now constrained within the XML.
      3. Parameterize LIMIT and OFFSET: Always use #{} for LIMIT and OFFSET values. These are often controlled by user input (e.g., pagination). This is a direct MyBatis interaction.
      4. MyBatis Timeout Configuration: Set timeout attribute in your statements. 
        <select id="findUsers" resultType="User" timeout="10">
  ...
</select>

    • Threats Mitigated:

      • SQL Injection (Severity: Critical): Attackers could inject malicious SQL into ORDER BY or LIMIT clauses.
      • Denial of Service (Severity: High): An attacker could provide a very large LIMIT value or a complex ORDER BY that causes performance issues.

    • Impact:

      • SQL Injection: Risk reduction: High (using the <choose> approach within MyBatis). Very High if combined with Java-side whitelisting.
      • Denial of Service: Risk reduction: High (by limiting the LIMIT value and setting timeouts).

    • Currently Implemented:

      • LIMIT and OFFSET are generally parameterized using #{}.
      • No timeout configuration

    • Missing Implementation:

      • orderMapper.xml: ORDER BY is still handled using ${}. The <choose> approach (or a Java-side whitelist) needs to be implemented.
      • Timeout configuration in all mappers.

Mitigation Strategy: Dynamic Table/Column Names (MyBatis-Specific Handling)

  • Mitigation Strategy: Dynamic Table/Column Names (MyBatis-Specific Handling)

    • Description:

      1. Identify dynamic table/column names: Locate any instances where table names or column names are dynamically generated based on input within your MyBatis XML mappers.
      2. Whitelist approach (Strongly Recommended, often best done outside MyBatis): Ideally, handle whitelisting in your Java service layer. However, if you must handle it within MyBatis, use the <choose>, <when>, <otherwise> structure, similar to the ORDER BY example above. This is less ideal than Java-side whitelisting because it can become complex and harder to maintain. 
        <select id="getData" resultType="MyData">
  SELECT
  <choose>
    <when test="columnName == 'col1'">col1</when>
    <when test="columnName == 'col2'">col2</when>
    <otherwise>default_col</otherwise>
  </choose>
  FROM
  <choose>
    <when test="tableName == 'table1'">table1</when>
    <when test="tableName == 'table2'">table2</when>
    <otherwise>default_table</otherwise>
  </choose>
</select>
      3. Avoid ${}: Absolutely avoid using ${} for dynamic table/column names with any input that could be influenced by a user. Even with the <choose> approach, ensure the variables passed to the mapper come from a trusted source.

    • Threats Mitigated:

      • SQL Injection (Severity: Critical): Dynamic table/column names are a high-risk area for SQL injection.
      • Information Disclosure (Severity: Medium): An attacker might be able to probe for the existence of tables or columns.

    • Impact:

      • SQL Injection: Risk reduction: High (with the <choose> approach within MyBatis, but ideally handled in Java).
      • Information Disclosure: Risk reduction: Moderate.

    • Currently Implemented:

      • No consistent approach is currently implemented.

    • Missing Implementation:

      • reportService.java: Uses string concatenation to build table names dynamically. This needs to be refactored, ideally to use a whitelist in Java, and then pass a safe table name to MyBatis.
      • dynamicColumnMapper.xml: Uses ${} for dynamic column names. This needs to be refactored to use the <choose> approach (or, preferably, a Java-side whitelist).

Mitigation Strategy: Disable DTDs (XXE Prevention - MyBatis Configuration)

  • Mitigation Strategy: Disable DTDs (XXE Prevention - MyBatis Configuration)

    • Description:

      1. Locate SqlSessionFactory creation: Find the code where the SqlSessionFactory is created (usually in a configuration class).
      2. Set the disableDtd property: Add the following code to disable DTDs: 
        configuration.setVariables(new Properties() {{
    setProperty("org.apache.ibatis.parsing.xml.disableDtd", "true");
}});
        This should be done before building the SqlSessionFactory. This is a direct configuration change to MyBatis.
      3. Verify custom XMLMapperEntityResolver (if any): If you have a custom XMLMapperEntityResolver, ensure it does not load external entities. The default XMLMapperEntityResolver is generally safe. This is a direct check of a MyBatis component.

    • Threats Mitigated:

      • XML External Entity (XXE) Injection (Severity: Critical): XXE attacks can allow attackers to read local files, access internal network resources, or cause a denial of service.

    • Impact:

      • XXE Injection: Risk reduction: Very High (eliminates the vulnerability if DTDs are not required).

    • Currently Implemented:

      • Not explicitly implemented.

    • Missing Implementation:

      • The disableDtd property should be explicitly set in the SqlSessionFactory configuration (MyBatisConfig.java).

Mitigation Strategy: Secure Logging (MyBatis-Specific Configuration)

  • Mitigation Strategy: Secure Logging (MyBatis-Specific Configuration)

    • Description:

      1. Identify logging configuration: Locate your logging configuration files (e.g., logback.xml, log4j2.xml).
      2. Set appropriate log levels for MyBatis: In production environments, set the logging level for MyBatis specifically to WARN or ERROR. This prevents sensitive SQL queries and parameters from being logged by MyBatis. Use DEBUG or TRACE only in development or testing environments. 
        <!-- Example for Logback -->
<logger name="org.apache.ibatis" level="WARN" />
<logger name="your.package.mappers" level="WARN" />
        This directly controls MyBatis' logging behavior.

    • Threats Mitigated:

      • Information Disclosure (Severity: Medium): Exposure of sensitive data (e.g., passwords, API keys) in logs generated by MyBatis.

    • Impact:

      • Information Disclosure: Risk reduction: High (if logging is configured correctly).

    • Currently Implemented:

      • Log levels are set to INFO in the production environment, which is too verbose.

    • Missing Implementation:

      • The log level for MyBatis and mapper packages needs to be changed to WARN in logback.xml (production profile).

Mitigation Strategy: Regular Updates (of MyBatis)

  • Mitigation Strategy: Regular Updates (of MyBatis)

    • Description:

      1. Check for updates: Regularly check the MyBatis website or GitHub repository for new releases.
      2. Review release notes: Read the release notes for each new version to see if any security vulnerabilities have been fixed in MyBatis itself.
      3. Update dependencies: Update the MyBatis dependency in your project's build file (e.g., pom.xml for Maven, build.gradle for Gradle). This directly updates the MyBatis library.
      4. Test: Thoroughly test the application after updating MyBatis to ensure that there are no regressions.

    • Threats Mitigated:

      • Known Vulnerabilities (Severity: Varies): Vulnerabilities discovered and fixed in newer versions of MyBatis.

    • Impact:

      • Known Vulnerabilities: Risk reduction: High (prevents exploitation of known vulnerabilities in MyBatis).

    • Currently Implemented:

      • No formal process for regular updates is in place.

    • Missing Implementation:

      • A process needs to be established to regularly check for and apply MyBatis updates.