Linux Simple attack and defense

First, Linux security introduction

1, the impression of Linux security

2, whether have encountered the invasion, what are the phenomena, how to solve the

3, the process of hacking, how to defend

Ii. Linux attack and defense

1, common Trojan control terminal function (10771TCP, 10991UDP, integrated Control terminal 6886) (Control side)

2. Trojan client type (Trojan) generator

3, the transmission of the horse invasion process

Way

3.1. Default port 22 Weak password blasting

3.2, 21 port, 3306 port, weak password blasting

3.3, Webshell for Shell bounce right

3.4, Trojan into the top of the server and execute, through the way of the Trojan to control your server, to do some illegal operation

Process

3.1, cut into/tmp directory

3.2, Wge download Trojan

3.3, Trojan Load permissions

3.4. Execution Trojan

3.5, back door, support wood Mar Woo

4, the symptoms after the invasion

Inexplicably CPU utilization is very high, intermittent

Third, how to clear the Trojan and back door

1. Clear the Trojan Horse

1.1, network connection, filter out the normal connection

Netstat-nalp | grep "TCP/UDP" | grep-v XXX |grep "established"

1.2, judge some abnormal connection, through the PID to find the process name, stop the process

Ps-ef | grep "3249"

Kill-9 Process Number

1.3. Find the source file by name, delete it

Find/-name "XXXX"

2, clear the backdoor (in the following file may appear the relevant command, find it, and delete)

2.1,/etc/rc.local

2.2,/crontab-l

2.3,/ROOT/.BASHRC ordinary users under the. BASHRC

2.4,/etc/profile Backup profile file diff Profile.bak whether there are different

This article is from the "Crystal" blog, so be sure to keep this source http://crystal3331.blog.51cto.com/2948719/1705485

Linux Simple attack and defense