master..sp_resolve_logins存储过程中,对@dest_path参数过滤不严,导致xp_cmdshell注入。
分析:
SELECT @dest_path = RTRIM(LTRIM(@dest_path))
-- If the last char is '\', remove it.
IF substring(@dest_path, len(@dest_path),1) = '\'
SELECT @dest_path = substring(@dest_path, 1, len(@dest_path)-1)
-- Don't do validation if it is a UNC path due to security problem.
-- If the server is started as a service using local system account, we
-- don't have access to the UNC path.
IF substring(@dest_path, 1,2) <> '\\'
BEGIN
SELECT @command = 'dir "' + @dest_path + '"'
exec @retcode = master..xp_cmdshell @command, 'no_output'
IF @@error <> 0
RETURN (1)
IF @retcode <> 0
BEGIN
raiserror (14430, 16, -1, @dest_path)
RETURN (1)
END
END
master..sp_resolve_logins存储过程 在这一段,经过一定的判断,对 @dest_path 进行了一定的过滤。
但是没有过滤"(双引号)导致了 xp_cmdshell执行任意SQL语句
MSSQL
用函数fn_escapecmdshellsymbolsremovequotes把@dest_path过滤就OK了。如:
SELECT @dest_path = RTRIM(LTRIM(fn_escapecmdshellsymbolsremovequotes(@dest_path))) ,这样就不会产生注入了。
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