Transcript Networking Security

Network Security
Kevin Diep
Outline
• The five phrases of network penetration
• How to prevent exploitations and network
vulnerability
• Ethical issues behind such attacks
Phase 1: Reconnaissance
• To collect and gain information
• Low-Technology Reconnaissance:
 Social Engineering
 Physical Break-In
 Dumpster Diving
Social Engineering
 Social engineering involves an attacker
calling employees at the target
organization on the phone and duping
them into revealing sensitive information
•
Finding pretext to obtain privileged
information or services
•
Social engineering is deception, pure and
simple.
Social Engineering
• Several of social engineering's "greatest hits"
are
 A new employee calls the help desk trying to
figure out how to perform a particular task on
the computer.
 An angry manager calls a lower level
employee because a password has suddenly
stopped working.
Social Engineering
 A system administrator calls an employee to
fix an account on the system, which requires
using a password.
 An employee in the field has lost some
important information and calls another
employee to get the remote access phone
number
Physical Break-In
• An external attacker might try to walk
through a building entrance, sneaking in
with a group of employees on their way into
work
• An attacker might simply try grabbing a USB
Thumb drive, CD, DVD, backup tape, hard
drive, or even a whole computer containing
sensitive data and walking out with it tucked
under a coat.
Dumpster Diving
• Retrieving sensitive information from trash
such ask discarded paper, CDs, DVDs,
floppy disks, tapes, and hard drives
containing sensitive data.
• Dumpster diving is especially effective when
used for corporate espionage
Phase 1: Reconnaissance
• Higher-Technology Reconnaissance:
 Searching the Web
 Using the Whois Database
Reconnaissance via Searching the
Web
• Searching an organization’s own web site
 Employees’ contact information and phone
numbers
 Clues about the corporate culture and
language
 Business partners
 Recent mergers and acquisitions
 Server and application platforms in use
Reconnaissance via Whois
Database
• These databases contain a variety of data
elements regarding the assignment of
domain names, individual contacts, and
even Internet Protocol (IP) addresses
Phase 2: Scanning
• After the reconnaissance phase, the
attacker is armed with some vital
information about the target infrastructure
a handful of telephone numbers, domain
names, IP addresses, and technical contact
information
• Most attackers then use this knowledge to
scan target systems looking for openings
Phase 2: Scanning
• War Dialing
• Network Mapping
• Port Scanning
War-dialing attack
• Searching for a modem in a target's telephone
exchange to get access to a computer on their
network
• You can manually do it yourself or use tools that
automates the task for you, dialing large pools of
telephone numbers in an effort to find unprotected
modems.
• These tools can scan in excess of 1,000 telephone
numbers in a single night using a single computer
with a single phone line
Phase 2: Network Mapping
• Finding live hosts
ICMP pings
Traceroute
• We can use this feature to determine the
paths that packets take across a network
Phase 2: Port Scanning
• Used software to find open ports
• Nmap, Strobe, Ultrascan
Phase 2: Scanning
What the Attacker Knows
Tools Used to Get the Information
List of addresses for live hosts on
the network
Ping and Cheops-ng
General network topology
Traceroute and Cheops-ng
List of open ports on live hosts
Nmap port scan
List of services and versions running
on the target ports
Nmap version scan
Operating system types of live hosts Nmap and Xprobe2 active
operating system fingerprinting
List of ports open through packet
filters on the target network
Firewalk
Phase 3: Gaining Access
• Gaining access to retrieve sensitive information
from the victim
• Use the victim as a launching platform to
attack other victim
• Destroy the victim file
• Two methods of gaining access
Gaining Access using Application and OS attacks
Gaining Access using Network attacks
Phase 3: Gaining Access Using
Application and OS Attacks
• Password attacks
• Web application attacks
Password Attacks
• Password Guessing Attacks
 Users often choose passwords that are easy
to remember, but are also easily guessed
 default passwords used by vendors left
unchanged
• Password Guessing Through Login Attacks
run a tool that repeatedly tries to log in to the
target system across the network, guessing
password after password
Phase 3: Password Cracking
• More sophisticated and faster than
password guessing through login script
• Requires access to a file containing user
names and encrypted passwords
Phase 3: Password Cracking
• A password-cracking tool can form its password
guesses in a variety of ways.
Words in the dictionary
• Many password-cracking tools also support bruteforce cracking
guesses every possible combination of characters to
determine the password (a–z and 0–9) and special
characters (!@#$, and so on).
this brute-force guessing process can take an
enormous amount of time, ranging from hours to
centuries
Phase 3: Gaining Access
• Web Application Attacks
Account Harvesting
SQL Piggy
Account Harvesting
User ID is incorrect
Password is incorrect
Account Harvesting
• Attackers can write a script to brute-force
guessing all possible user IDs using a false
password.
• If an error message is returned indicating
that the user ID is valid, they will store that to
a file, and reverse the process and guessing
the password for the successful ID they just
obtained.
SQL Piggybacking
• Attacker may can extend an application’s
SQL statement to extract or update
information that the attacker is not
authorized to access
• Attacker will explore how the Web
application interacts with the back-end
database by finding a user-supplied input
string that will be part of a database query
Phase 3: Gaining Access Using
Network Attacks
• Sniffing
• IP Spoofing
Phase 3: Sniffing
• Sniffer
Allows attacker to see everything sent across the
network, including userIDs and passwords
• Island Hopping Attack
Attacker initially takes over a machine via
some exploit
Attacker installs a sniffer to capture userIDs
and passwords to take over other machines
Phase 3: IP Spoofing
• Just change your IP address to the other
system's address
• If the attacker just wants to send packets
that look like they come from somewhere
else
Phase 4: Maintaining Access
• Trojan Horses
Software program containing a concealed
malicious capability but appears to be benign,
useful, or attractive to users
• Backdoor
Software that allows an attacker to access a
machine using an alternative entry method
Installed by attackers after a machine has been
compromised
May Permit attacker to access a computer
without needing to provide account names and
passwords
Phase 4: Maintaining Access
• Trojan Horse Backdoors
Programs that combine features of
backdoors and Trojan horses
 Not all backdoors are Trojan horses
 Not all Trojan horses are backdoors
Programs that seem useful but allows an
attacker to access a system and bypass
security controls
Phase 4: Maintaining Access
• Categories of Trojan Horse Backdoors
Application-level Trojan Horse Backdoor
 A separate application runs on the system that
provides backdoor access to attacker
Traditional RootKits
 Critical operating system executables are replaced
by attacker to create backdoors and facilitate
hiding
Kernel-level RootKits
 Operating system kernel itself is modified to allow
backdoor access and to help attacker to hide
Application-level Trojan Horse
Backdoor
• User must be tricked into installing this
application which gives attacker backdoor
access and complete control over victim’s
machine
Back Orifice 2000
• Tricking Users to install Trojan Backdoors
embed backdoor application in another
innocent looking program via “wrappers”
Wrapper creates one Trojan EXE application
from two separate EXE programs
Traditional RootKits
• A suite of tools that allow an attacker to maintain
root-level access via a backdoor and hiding
evidence of a system compromise
• More powerful than application-level Trojan horse
backdoors(eg. BO2K, Netcat) since the latter run as
separate programs which are easily detectable
• a more insidious form of Trojan horse backdoor than
application-level counterparts since existing critical
system components are replaced to let attacker
have backdoor access and hide
• A RootKit replaces /bin/login with a
modified version that includes a backdoor
password for root access
Kernel-Level RootKits
• More sinister, devious, and nasty than
traditional RootKits
• Operating system kernel replaced by a
Trojan horse kernel that appears to be wellbehaved but in actuality is rotten to the
core
• Trojanized kernel can intercept system calls
and run another application chosen by
atttacker
• File Hiding
Attacker can hide specific subdirectories and
files
• Process Hiding
Attacker can be running Netcat listener but
the kernel will not report its existence to ps
• Network Hiding
Attacker can tell kernel to lie to netstat about
network port being used by a backdoor
program
Phase 5: Covering Tracks and Hiding
• Hiding Evidence by Altering Event Logs
Attackers like to remove evidence from logs
associated with attacker’s gaining access,
elevating privileges,and installing RootKits and
backdoors
Create hidden file from the user
• Covert Channels
Communication channels that disguises data
while it moves across the network to avoid
detection
Can be used to remotely control a machine and
to secretly transfer files or applications
Preventing Exploitations
• Rule of thumb
▫ Don’t give out sensitive information to anyone
▫ Don’t let attacker get root or administrator
access on hosts
▫ Harden OS
▫ Install latest security patches
▫ Install network IDS
▫ Use antivirus tools
▫ Know your software
▫ Disable all unneeded services and ports
Is hacking ethical?
• http://www.computerworld.com/s/article/9154
9/Is_hacking_ethical_
• Hacktivists: Those who hack as a form of
political activism.
• Hobbyist hackers: Those who hack to learn, for
fun or to share with other hobbyists.
• Research and security hackers: Those
concerned with discovering security
vulnerabilities and writing the code fixes.
Conclusion
• “Yes, I do believe that hacking -- when
properly defined -- is an ethical activity.”
- By Marcia J. Wilson
• http://www.youtube.com/watch?v=dBSDfo
5g2tw&feature=related