Allowing the attacker to access unathorized records finding - asp.net

Question

I have a scan finding and hope someone can provide any ideas as to best ways to resolve the issue. First I will show the scan Finding then my code and finally what the scanner's recommended solution is.
Finding
Without proper access control, the method GetAttributeKey() in Provider.cs can execute a SQL statement on line 163 that contains an attacker-controlled primary key, thereby allowing the attacker to access unauthorized records.
Rather than relying on the presentation layer to restrict values submitted by the user, access control should be handled by the application and database layers. Under no circumstances should a user be allowed to retrieve or modify a row in the database without the appropriate permissions. Every query that accesses the database should enforce this policy, which can often be accomplished by simply including the current authenticated username as part of the query.
My Code:
Offending line:
myParam.SqlParam.Value = attribute;
Method:
public string GetAttributeKey(string attribute)
{
string qry = "SELECT ws_attribute_key FROM webservice_attributes WHERE ws_attribute = #attribute";
QueryContainer Instance = new QueryContainer(qry);
MyParam myParam = new MyParam();
myParam.SqlParam = new SqlParameter("#attribute", Instance.AddParameterType(_DbTypes._string));
myParam.SqlParam.Value = attribute;
Instance.parameterList.Add(myParam);
object key = ExecuteScaler(Instance);
return Convert.ToString(key);
}
Scanner's Recommend fix:
string user = ctx.getAuthenticatedUserName();
int16 id = System.Convert.ToInt16(invoiceID.Text);
SqlCommand query = new SqlCommand(
"SELECT * FROM invoices WHERE id = #id AND user = #user", conn);
query.Parameters.AddWithValue("#id", id);
query.Parameters.AddWithValue("#user", user);
SqlDataReader objReader = query.ExecuteReader();
I think the problem is dealing with the code calling the GetAttributeKey. The method is called only if the user has no access to to the Attribute. I think I need some type of checking. Here is the calling code:
if (result.Rows.Count > 0)
{
// get the attribute
DataRow[] rows = result.Select("ws_attribute = '" + attribute + "'");
if (rows.Length > 0)
{
// check time range
string hr = DateTime.Now.Hour.ToString();
DataRow[] valid = result.Select("ws_attribute = '" + attribute + "' AND start_time <= " + hr + " AND end_time >= " + hr);
if (valid.Length > 0)
{
ws_user_attribute_key = Convert.ToInt32(valid[0]["ws_user_attribute_key"].ToString());
ret = true;
// generate salt
TextEncryptor te = new TextEncryptor();
salt = te.CreateSalt(8);
// save to the log, return false if failed to log
if (!LogTransfer(ipAddress, accessDate, fileName, ws_user_attribute_key, salt, out logKey))
return false;
}
else
{
ret = false;
LogInvalidAccess(username, rows[0]["ws_attribute_key"].ToString(), ipAddress, accessDate, WSInvalidAccessReason.OutsideValidTimeRange);
}
}
else
{
// if user has no access to attribute
ret = false;
LogInvalidAccess(username, GetAttributeKey(attribute), ipAddress, accessDate, WSInvalidAccessReason.AttributeNotAccessible);
}
}
else
{
ret = false;
LogInvalidAccess(username, GetAttributeKey(attribute), ipAddress, accessDate, WSInvalidAccessReason.InvalidAccount);
}