snmp

• SNMP Agent Default Community Name (public)
  修改配置文件/etc/snmp/snmpd.conf将Public改成其他具有复杂度的字符串如Admin123...，保存后重新启动SNMP服务即可。
  

  [root@localhost ~]# nmap -sU -p161 -script=snmp-brute 127.0.0.1
  
  Starting Nmap 6.40 ( http://nmap.org ) at 2021-11-09 07:35 CST
  Nmap scan report for localhost (127.0.0.1)
  Host is up (0.000033s latency).
  PORT    STATE  SERVICE
  161/udp closed snmp
  
  Nmap done: 1 IP address (1 host up) scanned in 0.27 seconds

• SNMP 'GETBULK' Reflection DDoS
  使用net-snmp-create-v3-user命令进行snmp v3配置(需要再snmp服务停止的状态下才能生效)

  [root@VM_Server ~]# net-snmp-create-v3-user
  Enter a SNMPv3 user name to create: 
  snmpuser
  Enter authentication pass-phrase: 
  snmpv3@2020md5
  Enter encryption pass-phrase: 
    [press return to reuse the authentication pass-phrase]
  snmpv3@2020des
  adding the following line to /var/lib/net-snmp/snmpd.conf:
     createUser snmpuser MD5 "snmpv3@2020md5" DES snmpv3@2020des
  adding the following line to /etc/snmp/snmpd.conf:
     rwuser snmpuser

  生效后可以查看到配置文件中的新增
  

  启动snmp服务后，使用snmpwalk命令验证

  snmpwalk -v3 -usnmpuser -lauth -aMD5 -A"snmpv3@2020md5" -X"snmpv3@2020des" 127.0.0.1

   

samba

• SMB Signing not required
  修改配置文件/etc/samba/smb.conf，将client signing = mandatory和server signing = mandatory添加到[global]后保存文件，然后重启samba服务

  [root@localhost ~]# nmap -sS -sV -Pn -p 445 --script="smb-security-mode" 127.0.0.1
  
  Starting Nmap 6.40 ( http://nmap.org ) at 2021-11-09 07:22 CST
  Nmap scan report for localhost (127.0.0.1)
  Host is up (0.000032s latency).
  PORT    STATE SERVICE     VERSION
  445/tcp open  netbios-ssn Samba smbd 3.X (workgroup: LOCALHOST)
  
  Host script results:
  | smb-security-mode: 
  |   Account that was used for smb scripts: guest
  |   User-level authentication
  |   SMB Security: Challenge/response passwords supported
  |_  Message signing required
  
  Service detection performed. Please report any incorrect results at http://nmap.org/submit/ .
  Nmap done: 1 IP address (1 host up) scanned in 6.38 seconds
  

ssh

• SSH Server CBC Mode Ciphers Enabled

  修改/etc/ssh/sshd_config文件，最后一行添加如下内容
   

  Ciphers aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,arcfour
  
  Macs hmac-sha1,hmac-ripemd160

  使用ssh命令验证

  ssh -vv -oCiphers=aes128-cbc,3des-cbc,blowfish-cbc  目标IP
  ssh -vv -oMACs=hmac-md5  目标IP

  
  使用Nmap验证

  nmap --script ssh2-enum-algos -sV -p 22  目标IP