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Hacker, Cracker?!
 Are
they the same?
No!!!
Hacker
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programmers
intensely interested in the arcane and recondite
workings of any computer operating system.
advanced knowledge of operating systems and
programming languages.
–
know of holes within systems and the reasons for such holes.
Hackers constantly seek further knowledge, freely share what
they have discovered, and never, ever intentionally damage
data.
Cracker
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breaks into or otherwise violates the system integrity of
remote machines, with malicious intent.
having gained unauthorized access, destroy vital data,
deny legitimate users service, or basically cause
problems for their targets.
can easily be identified because their actions are
malicious.
Tools for hacking
Scanners
Trojan Horses
Packet sniffing
Password Cracker
Scanners
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In Internet security, no hacking tool is more celebrated
than the scanner.
good TCP port scanner is worth a thousand user
passwords.
What Is a Scanner?
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program
– automatically detects security weaknesses in a
remote or local host.
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important to Internet security
– reveal weaknesses in the network
How Do Scanners Work?
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Every PC has 65535 port
TCP port scanners programs which
– attack TCP/IP ports and services (Telnet or FTP, for
example) and record the response from the target.
– glean valuable information about the target host
What Will a Scanner Tell Me?
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reveal certain inherent weaknesses within the target
host.
– These might be key factors in implementing an
actual compromise of the target's security.
What Won't a Scanner Tell Me?
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A step-by-step method of breaking in
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The degree to which your scanning activity has been
logged
Password Cracker
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Program
– can decrypt passwords or otherwise disable
password protection.
– Most of them need not decrypt anything.Real
encrypted passwords cannot be reverse-decrypted.
Packet sniffing
program
captures data from information packets as they travel over
the network.
data may include
user names, passwords, and proprietary information that travels
over the network in clear text.
With perhaps hundreds or thousands of passwords captured
by the packet sniffer, intruders can launch widespread
attacks on systems.
Installing a packet sniffer does not necessarily require
administrator-level access.
Trojan horse
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program
– containing hidden functions
 can exploit the privileges of the user [running the
program], with a resulting security threat.
– does things that the program user did not intend
rely on users to install them
can be installed by intruders who have gained
unauthorized access by other means.
What do Trojan horses do?
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can do anything that the user executing the program
has the privileges to do.Include:
– deleting files that the user can delete
– transmitting to the intruder any files that the user
can read
– changing any files the user can modify installing
viruses
– installing other Trojan horses
–
installing other programs with the privileges of the
user
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–
programs that provide unauthorized network access
executing privilege-elevation attacks
Example of Trojans
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Back Orifice
NetBus
The most common attack
DDoS
DDoS
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DDoS(distributed denial-of-service)
DoS
– is called a attack(denial-of-service DoS)
causes your computer to crash or to become so busy
processing data that you are unable to use it
Ping of Death
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Sending too large ping request.
Fragmentation allow to send this large packet.
– When packet re-combine,this will overload the buffer.
SYN Flooding
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Send tons of SYN(SYNchronize) request to server
When server send SYN-ACK(ACKnowledge)
response,it can’t send the last acknowledgment
request.
Result- use up the network buffer.
Contributes of hacker??
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Linux is written by hacker!!
The End