解决2020kali新版本msfconsole启动失败

1. Kali Linux 2020.1a系统安装后，启动msfconsole将出现如下错误：

root@kali:~# msfconsole 
[*] Bundler failed to load and returned this error:
   'cannot load such file -- bundler / setup'
[*] You may need to uninstall or upgrade bundler

2. 由于默认安装的bundler为最新版本2.1.4。msfconsole依赖的版本为1.17.3，所以需要安装旧版本。执行如下命令：

gem install bundler:1.17.3

3. 如果超时报错

执行gem install bundler后报错：
ERROR: Could not find a valid gem ‘bundler’ (>= 0), here is why:
Unable to download data from https://ruby.taobao.org/ - SSL_connect returned=1 errno=0 state=SSLv3 read server certificate B: certificate verify failed (https://ruby.taobao.org/specs.4.8.gz)

4. 检查现在用的源

gem sources -l

5. 添加新的源，删除原来的旧源

gem sources --add https://gems.ruby-china.com/ --remove https://rubygems.org/

6. 确保只有一个源

gem sources -l