What are SQL Injections?
SQL injection is a web security vulnerability that enables an attacker to interfere with the queries an application sends to its database. In the context of ColdFusion, one of the best strategies to prevent SQL injection attacks is to sanitize queries using the CFQueryParam tag.
What is CFQueryParam?
CFQueryParam is a powerful tool in the ColdFusion developer’s arsenal. It verifies the data type of a query parameter and, if the current user is authorized, the tag also performs a range check.
The goal of this article will be to guide you through the steps to sanitize your queries in ColdFusion using CFQueryParam.
1. Understanding SQL Injections
To prevent SQL injections, you first need to understand them. SQL injections typically occur when you ask a user for input and then include that input in an SQL query. If the user provides a value that modifies the SQL query, they can control the behavior of the query in unintended ways. This can lead to unauthorized data access or data corruption.
2. Basic Implementation of CFQueryParam
The basic usage of CFQueryParam is straightforward. In ColdFusion, whenever you construct an SQL query that incorporates user input, it is essential to pass that specific part of the query through the CFQueryParam tag.
Here is a simple example of how you would use it:
<cfquery name="getProducts" datasource="myDataSource">
SELECT * FROM Products WHERE CategoryID = <cfqueryparam value="#URL.CategoryID#" cfsqltype="cf_sql_integer">
</cfquery>
In this example, #URL.CategoryID# is a piece of user input that is included in an SQL query. By using CFQueryParam, the value of URL.CategoryID is treated as a single literal value, preventing it from modifying the structure of the SQL query.
3. Use the Correct CFSQLType
The cfsqltype attribute should be set to match the database column’s data type. This ensures that the data the user provides is of the correct type, helping to prevent SQL injection attacks. If the data type does not match the column’s data type, ColdFusion throws an error, preventing the query from running.
Here is a list of some common cfsqltype values:
- cf_sql_integer
- cf_sql_float
- cf_sql_double
- cf_sql_date
- cf_sql_timestamp
- cf_sql_varchar
- cf_sql_longvarchar
Full list of cfsqltypes
CF_SQL_BIGINT
CF_SQL_BIT
CF_SQL_CHAR
CF_SQL_BLOB
CF_SQL_CLOB
CF_SQL_DATE
CF_SQL_DECIMAL
CF_SQL_DOUBLE
CF_SQL_FLOAT
CF_SQL_IDSTAMP
CF_SQL_INTEGER
CF_SQL_LONGNVARCHAR
CF_SQL_LONGVARCHAR
CF_SQL_MONEY
CF_SQL_MONEY4
CF_SQL_NCHAR
CF_SQL_NCLOB
CF_SQL_NVARCHAR
CF_SQL_NUMERIC
CF_SQL_REAL
CF_SQL_REFCURSOR
CF_SQL_SMALLINT
CF_SQL_SQLXML
CF_SQL_TIME
CF_SQL_TIMESTAMP
CF_SQL_TINYINT
CF_SQL_VARCHAR
4. Utilize the Maximum Length Attribute
The maxlength attribute is used to set the maximum length of the input parameter.
By implementing this approach, an extra level of security is ensured by preventing excessively long inputs that could potentially be exploited for buffer overflow attacks or for submitting sizable payloads of malicious code.
<cfqueryparam value="#form.username#" cfsqltype="cf_sql_varchar" maxlength="20">
5. Leverage the Null Attribute
The null attribute allows a query parameter to be null. When the null attribute is set to “yes” in CFQueryParam, an empty or absent value is interpreted as null. This feature proves beneficial when dealing with optional form fields that correspond to nullable database columns.
<cfqueryparam value="#form.optionalField#" cfsqltype="cf_sql_varchar" null="#yesNoFormat(len(trim(form.optionalField)) EQ 0)#">
If you have any questions or encounter issues, please don’t hesitate to reach out to [email protected].