原文地址：http://blog.csdn.net/yinjiabin/article/details/7590750
1、sql特殊字符带来的问题
在sql语句中，有些特殊字符，是sql保留的。比如 ' [ ] 等。我们可以先看看它们的用法。
当需要查询某数据时，加入条件语句，或着当你需要insert记录时，我们用 ' 来将字符类型的数据引起来。比如：
Select * from Customers where City = 'London'
当表的名字或列的名字中，含有空格等一些特殊字符时，我们需要用[] 将表名引起来，告诉语法分析器，[]号内的才是一个完整的名称。比如
Select * from [Order Details]
如果，字符数据中，含有 ' 改怎么办呢？其实，好多人在这里并没有处理字符川中 ' 符号，才造成sql 注射危险。就那上面的那个例子。在Sql语句拼接的时代，比如
string sql = "select * from Customers where CustomerID = '" + temp + "'";
如果，我给temp赋值为 Tom' or 1=1 ---
那么你拼接起来的语句为 select * from Customers where CustomerID = 'Tom' or 1=1 --- '
哈哈，1=1 衡为真，---会把后面的sql语句注释掉。而前面因为有输入的 ' 而使的语句是合法的。那or的条件，会把所有的记录都选出来。这就是sql注入。在做用户登陆时，如果没有处理该问题，那你的系统受危害的可能性会很高的。
如何处理字符数据中的 ' 符号呢？ 方法很简单，用两个 ' 符号代替一个。 比如，其实际传入的值为Lon'don，处理后为
Select * from Customers where City = 'Lon''don'
就可以了。
如果表或列的名称中含有 [ 或 ] 字符呢？比如Select * from [Order] Details]，那中间 ] 符号岂不是先和第一个[ 配了。后面的就是非法的了。怎么办呢？ 简单，使用 ]] 代替 ] 。对于[，则无须处理。那就该为
Select * from [Order]] Details]。
2、解决方法(过滤sql特殊字符方法集合 )
1.
/// <summary>
/// 过滤不安全的字符串
/// </summary>
/// <param name="Str"></param>
/// <returns></returns>
public static string FilteSQLStr(string Str)
{
Str = Str.Replace("'", "");
Str = Str.Replace("\"", "");
Str = Str.Replace("&", "&");
Str = Str.Replace("<", "<");
Str = Str.Replace(">", ">");
Str = Str.Replace("delete", "");
Str = Str.Replace("update", "");
Str = Str.Replace("insert", "");
return Str;
}
2.
#region 过滤 Sql 语句字符串中的注入脚本
/// <summary>
/// 过滤 Sql 语句字符串中的注入脚本
/// </summary>
/// <param name="source">传入的字符串</param>
/// <returns>过滤后的字符串</returns>
public static string SqlFilter(string source)
{
//单引号替换成两个单引号
source = source.Replace("'", "''");
//半角封号替换为全角封号，防止多语句执行
source = source.Replace(";", "；");
//半角括号替换为全角括号
source = source.Replace("(", "（");
source = source.Replace(")", "）");
///////////////要用正则表达式替换，防止字母大小写得情况////////////////////
//去除执行存储过程的命令关键字
source = source.Replace("Exec", "");
source = source.Replace("Execute", "");
//去除系统存储过程或扩展存储过程关键字
source = source.Replace("xp_", "x p_");
source = source.Replace("sp_", "s p_");
//防止16进制注入
source = source.Replace("0x", "0 x");
return source;
}
#endregion
3.
/// 过滤SQL字符。
/// </summary>
/// <param name="str">要过滤SQL字符的字符串。</param>
/// <returns>已过滤掉SQL字符的字符串。</returns>
public static string ReplaceSQLChar(string str)
{
if (str == String.Empty)
return String.Empty; str = str.Replace("'", "‘");
str = str.Replace(";", "；");
str = str.Replace(",", ",");
str = str.Replace("?", "?");
str = str.Replace("<", "＜");
str = str.Replace(">", "＞");
str = str.Replace("(", "(");
str = str.Replace(")", ")");
str = str.Replace("@", "＠");
str = str.Replace("=", "＝");
str = str.Replace("+", "＋");
str = str.Replace("*", "＊");
str = str.Replace("&", "＆");
str = str.Replace("#", "＃");
str = str.Replace("%", "％");
str = str.Replace("$", "￥");
return str;
}
4.
/// <summary>
/// 过滤标记
/// </summary>
/// <param name="NoHTML">包括HTML，脚本，数据库关键字，特殊字符的源码 </param>
/// <returns>已经去除标记后的文字</returns>
public string NoHtml(string Htmlstring)
{
if (Htmlstring == null)
{
return "";
}
else
{
//删除脚本
Htmlstring = Regex.Replace(Htmlstring, @"<script[^>]*?>.*?</script>", "", RegexOptions.IgnoreCase);
//删除HTML
Htmlstring = Regex.Replace(Htmlstring, @"<(.[^>]*)>", "", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"([\r\n])[\s]+", "", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"-->", "", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"<!--.*", "", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(quot|#34);", "\"", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(amp|#38);", "&", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(lt|#60);", "<", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(gt|#62);", ">", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(nbsp|#160);", " ", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(iexcl|#161);", "\xa1", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(cent|#162);", "\xa2", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(pound|#163);", "\xa3", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&(copy|#169);", "\xa9", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, @"&#(\d+);", "", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, "xp_cmdshell", "", RegexOptions.IgnoreCase);
//删除与数据库相关的词
Htmlstring = Regex.Replace(Htmlstring, "select", "", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, "insert", "", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, "delete from", "", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, "count''", "", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, "drop table", "", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, "truncate", "", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, "asc", "", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, "mid", "", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, "char", "", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, "xp_cmdshell", "", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, "exec master", "", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, "net localgroup administrators", "", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, "and", "", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, "net user", "", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, "or", "", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, "net", "", RegexOptions.IgnoreCase);
//Htmlstring = Regex.Replace(Htmlstring, "*", "", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, "-", "", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, "delete", "", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, "drop", "", RegexOptions.IgnoreCase);
Htmlstring = Regex.Replace(Htmlstring, "script", "", RegexOptions.IgnoreCase);
//特殊的字符
Htmlstring = Htmlstring.Replace("<", "");
Htmlstring = Htmlstring.Replace(">", "");
Htmlstring = Htmlstring.Replace("*", "");
Htmlstring = Htmlstring.Replace("-", "");
Htmlstring = Htmlstring.Replace("?", "");
Htmlstring = Htmlstring.Replace("'", "''");
Htmlstring = Htmlstring.Replace(",", "");
Htmlstring = Htmlstring.Replace("/", "");
Htmlstring = Htmlstring.Replace(";", "");
Htmlstring = Htmlstring.Replace("*/", "");
Htmlstring = Htmlstring.Replace("\r\n", "");
Htmlstring = HttpContext.Current.Server.HtmlEncode(Htmlstring).Trim();
return Htmlstring;
}
}
5.
public static bool CheckBadWord(string str)
{
string pattern = @"select|insert|delete|from|count\(|drop table|update|truncate|asc\(|mid\(|char\(|xp_cmdshell|exec master|netlocalgroup administrators|net user|or|and";
if (Regex.IsMatch(str, pattern, RegexOptions.IgnoreCase))
return true;
return false;
}
public static string Filter(string str)
{
string[] pattern ={ "select", "insert", "delete", "from", "count\\(", "drop table", "update", "truncate", "asc\\(", "mid\\(", "char\\(", "xp_cmdshell", "exec master", "netlocalgroup administrators", "net user", "or","and" };
for (int i = 0; i < pattern.Length; i++)
{
str = str.Replace(pattern[i].ToString(), "");
}
return str;
}