Social Attacking
As an administrator,we must pay attention to the security of system.Some people ofen required to need those information,maybe this is not necessary.we could identify their privilege and the reason given by them.Hackers want others take their suggestion,however, when it is happened to the hackers themselves,they will never do it.Hmmm,it seems that there will be other better ways completing the mission.
Check the strangers’s ID and identify their telephone number’s reality,or contact with their masters for identifing their information supplied.It is useful.We shoule learn to say no.Believe ours feeling which always is right for our decision.Trainning the users is also useful to decrease these matters that the whole systems are hacked and can not work any more.
Hackers will collect these information:Employee’s Item,telephone system structure,officer’s structure and the employee’s homepage.Even they searche the key work about people who they are intrested in the Internet,for example,Google website.The more information hackers know,the more easily they could control the target system.The following website maybe useful:www.hacklinux.com.
wget is used to download from internet.
# wget
find differences between two files.
# diff
Many hackers write those special code into the general source code so that they could use these “backdoors” to access the target servers.So we should check the integrity of the source codes between the original codes and those we download from internet.The following commands would be issues for checking :
# md5sum # sum
What is sum?checksum and count the blocks in a file.There are two types algorithm for sum command:
-BSD algorithm
# sum -r
-System V algorithm
# sum -s
We can also check the signatures of rpm packages:
# rpr --chechsig program.rpm
Gnu Privacy Guard(gpg),encryption and signing tool.It is not easily for Linux to be destoried by virtus,but worms could have great effect to Linux system.Morris worm(born in 1998) and Ramen worm(born in 2001) are the only two worms to UNIX systems.
Some people would like to install two different systems in one machine,for example,windows operating system and Linux.However,it is not safety.If the hackers have conquered one system,for example windows,they could delete the partition of Linux file system.So Linux is destroied.It is strongly recommended that we would not install two operating system in the same machine.
How to prevent the hackers used floppy or CD-ROM to access your system?First,in the BIOS setting,change the sequence of booting so that harddisk is in the first position,and then mask the option of floppy and CD-ROM,setting the bios password for the superuser.howerver,hackers could open the chassis and flashing the bios so that floppy and CD-ROM could be used again.In this way,choosing a security room to hold the servers machine is more and more necessary.