POC详情: e11fe3bf1398695a3ae01994c167e10f3c551374

来源
关联漏洞
标题: libssh server-side state machine 安全漏洞 (CVE-2018-10933)
描述:libssh是一个用于访问SSH服务的C语言开发包,它能够执行远程命令、文件传输,同时为远程的程序提供安全的传输通道。server-side state machine是其中的一个服务器端状态机。 libssh的server-side state machine 0.7.6之前版本和0.8.4之前版本中存在安全漏洞。攻击者可借助恶意的客户端利用该漏洞在不进行身份验证的情况下创建通道,进而获取未授权的访问权限。
介绍
# libSSH-Authentication-Bypass
Spawn to shell without any credentials by using CVE-2018-10933

Information about CVE-2018-10933 by libSSH : https://www.libssh.org/security/advisories/CVE-2018-10933.txt

Bugfix Release by libSSH : https://www.libssh.org/2018/10/16/libssh-0-8-4-and-0-7-6-security-and-bugfix-release/

## Find the right server with these fingerprints:
https://gist.github.com/0x4D31/35ddb0322530414bbb4c3288292749cc

## Generate Fake SSH Key for bypasswithfakekey.py:
https://help.github.com/articles/generating-a-new-ssh-key-and-adding-it-to-the-ssh-agent/

## Create a ssh server that vulnerable to channels OR directly use tool to bypass remote server:

**Important** : "People trying to reproduce libssh bug: the sample code (samplesshd-cb) is not vuln because it has explicit auth handlers. You can open a channel but nothing will happen."

As we can see this section is just for opening channel. You can't spawn to a shell in server that ran by "samplesshd-cb"

**It's just for opening channel. PoCs that i wrote is just for remote hosts.**

Download, uncompress and build the vulnerable libSSH Version : https://www.libssh.org/files/0.7/libssh-0.7.4.tar.xz

And then compile and run libSSH on your own server with ssh.

```
PWD: /libssh-0.7.4/build/examples/samplesshd-cb
./samplesshd-cb --dsakey==yourdsakey 127.0.0.1 --port=2222
```

## libSSH Authentication Bypass with two different tools
**If you have got any fake ssh keys use the second bypasswithfakekey.py**
```
pip install -r requirements.txt
If paramiko==2.0.8 doesn't works try : pip install paramiko==2.4.2

python libsshauthbypass.py --help
python bypasswithfakekey.py --help
```

## Shodan.io libSSH

![](https://i.imgur.com/SWEfcGR.png)
文件快照

[4.0K] /data/pocs/e11fe3bf1398695a3ae01994c167e10f3c551374 ├── [1.9K] bypasswithfakekey.py ├── [1.4K] libsshauthbypass.py ├── [1.7K] README.md └── [ 16] requirements.txt 0 directories, 4 files
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