最好的辦法就是不寫拼接SQL，改用參數(shù)化SQL，推薦新項目使用。這里不做介紹，感興趣的朋友可以自行搜索一下，本文介紹的方法適合老項目，就是沒有使用參數(shù)化SQL開發(fā)的程序。
將SQL一些危險的關鍵字，還有注釋百分號以及分號這些根本在我們正常寫代碼的時候根本不會出現(xiàn)的字符都過濾掉，這樣能最大限度的保證SQL執(zhí)行是安全的，代碼如下：
public class SqlFilter
{
public static void Filter()
{
string fileter_sql = "execute,exec,select,insert,update,delete,create,drop,alter,exists,table,sysobjects,truncate,union,and,order,xor,or,mid,cast,where,asc,desc,xp_cmdshell,join,declare,nvarchar,varchar,char,sp_oacreate,wscript.shell,xp_regwrite,',%,;,--";
try
{
// -----------------------防 Post 注入-----------------------
if (HttpContext.Current.Request.Form != null)
{
PropertyInfo isreadonly = typeof(System.Collections.Specialized.NameValueCollection).GetProperty("IsReadOnly", BindingFlags.Instance | BindingFlags.NonPublic);
//把 Form 屬性改為可讀寫
isreadonly.SetValue(HttpContext.Current.Request.Form, false, null);
for (int k = 0; k System.Web.HttpContext.Current.Request.Form.Count; k++)
{
string getsqlkey = HttpContext.Current.Request.Form.Keys[k];
string sqlstr = HttpContext.Current.Request.Form[getsqlkey];
string[] replace_sqls = fileter_sql.Split(',');
foreach (string replace_sql in replace_sqls)
{
sqlstr = Regex.Replace(sqlstr, replace_sql, "", RegexOptions.IgnoreCase);
}
HttpContext.Current.Request.Form[getsqlkey] = sqlstr;
}
}
// -----------------------防 GET 注入-----------------------
if (HttpContext.Current.Request.QueryString != null)
{
PropertyInfo isreadonly = typeof(System.Collections.Specialized.NameValueCollection).GetProperty("IsReadOnly", BindingFlags.Instance | BindingFlags.NonPublic);
//把 QueryString 屬性改為可讀寫
isreadonly.SetValue(HttpContext.Current.Request.QueryString, false, null);
for (int k = 0; k System.Web.HttpContext.Current.Request.QueryString.Count; k++)
{
string getsqlkey = HttpContext.Current.Request.QueryString.Keys[k];
string sqlstr = HttpContext.Current.Request.QueryString[getsqlkey];
string[] replace_sqls = fileter_sql.Split(',');
foreach (string replace_sql in replace_sqls)
{
sqlstr = Regex.Replace(sqlstr, replace_sql, "", RegexOptions.IgnoreCase);
}
HttpContext.Current.Request.QueryString[getsqlkey] = sqlstr;
}
}
// -----------------------防 Cookies 注入-----------------------
if (HttpContext.Current.Request.Cookies != null)
{
PropertyInfo isreadonly = typeof(System.Collections.Specialized.NameValueCollection).GetProperty("IsReadOnly", BindingFlags.Instance | BindingFlags.NonPublic);
//把 Cookies 屬性改為可讀寫
isreadonly.SetValue(HttpContext.Current.Request.Cookies, false, null);
for (int k = 0; k System.Web.HttpContext.Current.Request.Cookies.Count; k++)
{
string getsqlkey = HttpContext.Current.Request.Cookies.Keys[k];
string sqlstr = HttpContext.Current.Request.Cookies[getsqlkey].Value;
string[] replace_sqls = fileter_sql.Split(',');
foreach (string replace_sql in replace_sqls)
{
sqlstr = Regex.Replace(sqlstr, replace_sql, "", RegexOptions.IgnoreCase);
}
HttpContext.Current.Request.Cookies[getsqlkey].Value = sqlstr;
}
}
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
}
}
