問題背景：由于公司需要整改的老系統(tǒng)的漏洞檢查，而系統(tǒng)就是沒有使用參數(shù)化SQL即拼接查詢語句開發(fā)的程序，導(dǎo)致漏洞掃描出現(xiàn)大量SQL注入問題。

解決方法：最好的辦法就是不寫拼接SQL，改用參數(shù)化SQL，推薦新項(xiàng)目使用，老項(xiàng)目改起來比較麻煩，花費(fèi)的時(shí)間也多，最后選擇用全局SQL過濾器過濾前端發(fā)送的請(qǐng)求內(nèi)容。

代碼：文章來源地址http://www.zghlxwxcb.cn/news/detail-801605.html

/// <summary>
    /// 防止輸入?yún)?shù)sql注入：Post Get Cookies
    /// </summary>
    public class SqlFilter : ActionFilterAttribute
    {
        private const string FilterSql = "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,',%,;,--";

        public override void OnActionExecuting(ActionExecutingContext filterContext)
        {
            // -----------------------防 Post 注入-----------------------
            if (filterContext.HttpContext.Request.Form != null)
            {
                var isReadonly = typeof(System.Collections.Specialized.NameValueCollection).GetProperty("IsReadOnly", BindingFlags.Instance | BindingFlags.NonPublic);
                //把 Form 屬性改為可讀寫
                isReadonly?.SetValue(filterContext.HttpContext.Request.Form, false, null);

                for (var k = 0; k < filterContext.HttpContext.Request.Form.Count; k++)
                {
                    var inputKey = filterContext.HttpContext.Request.Form.Keys[k];
                    var inputValue = filterContext.HttpContext.Request.Form[inputKey];
                    var filters = FilterSql.Split(',');
                    inputValue = filters.Aggregate(inputValue, (current, filterSql) => Regex.Replace(current, filterSql, "", RegexOptions.IgnoreCase));
                    filterContext.HttpContext.Request.Form[inputKey] = inputValue;
                }
            }


            // -----------------------防 GET 注入-----------------------
            if (filterContext.HttpContext.Request.QueryString != null)
            {
                var isReadonly = typeof(System.Collections.Specialized.NameValueCollection).GetProperty("IsReadOnly", BindingFlags.Instance | BindingFlags.NonPublic);
                //把 QueryString 屬性改為可讀寫
                isReadonly?.SetValue(filterContext.HttpContext.Request.QueryString, false, null);

                for (var k = 0; k < filterContext.HttpContext.Request.QueryString.Count; k++)
                {
                    var inputKey = filterContext.HttpContext.Request.QueryString.Keys[k];
                    var inputValue = filterContext.HttpContext.Request.QueryString[inputKey];
                    var filters = FilterSql.Split(',');
                    inputValue = filters.Aggregate(inputValue, (current, filterSql) => Regex.Replace(current, filterSql, "", RegexOptions.IgnoreCase));
                    filterContext.HttpContext.Request.QueryString[inputKey] = inputValue;
                }
            }


            // -----------------------防 Cookies 注入-----------------------
            if (filterContext.HttpContext.Request.Cookies.Count > 0)
            {
                var isReadonly = typeof(System.Collections.Specialized.NameValueCollection).GetProperty("IsReadOnly", BindingFlags.Instance | BindingFlags.NonPublic);
                //把 Cookies 屬性改為可讀寫
                isReadonly?.SetValue(filterContext.HttpContext.Request.Cookies, false, null);

                for (var k = 0; k < filterContext.HttpContext.Request.Cookies.Count; k++)
                {
                    var inputKey = filterContext.HttpContext.Request.Cookies.Keys[k];
                    var inputValue = filterContext.HttpContext.Request.Cookies[inputKey]?.Value;
                    var filters = FilterSql.Split(',');
                    inputValue = filters.Aggregate(inputValue, (current, filterSql) => Regex.Replace(current, filterSql, "", RegexOptions.IgnoreCase));
                    if (!(filterContext.HttpContext.Request.Cookies[inputKey] is null))
                    {
                        filterContext.HttpContext.Request.Cookies[inputKey].Value = inputValue;
                    }
                }
            }
            base.OnActionExecuting(filterContext);
        }
    }

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