Download Hacking - Computer Engineering

COEN 252
Security Threats
Network Based Exploits
Phases of an Attack
Reconnaissance
 Scanning
 Gaining Access
 Expanding Access
 Covering Tracks
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Reconnaissance
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Social Engineering
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“I cannot access my email. What do I do?”
Dumpster Diving (especially useful when
people move)
Search the Web
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Sam Spade (www.samspade.org/ssw/),
CyberKit, NetScanTools, ...
Search Engine
Usenet postings
Whois
Reconnaissance
Databases
 To research .com , .net, and .org domain
names:InterNIC whois feature:
www.internic.net/whois.html allwhois,
network soultions, ...
 ARIN: American Registry for Interent
Numbers (www.arin.net/whoiis/arinwhois.html)
 RIPE (Europe) www.ripe.net
 APNIC (Asia Pacific) www.apnic.net
Reconnaissance: Scanning
Once we have a target, we need to get to
know it better.
Methods:
 War Dialing (to find out modem access)
 Network Mapping
 Vulnerability Scanning
 War Driving
Scanning: War Dialing
Purpose: Find a modem connection.
 Many users in a company install remote PC
software such as PCAnywhere without setting the
software up correctly.
 War Dialer finds these numbers by going through
a range of phone numbers listening for a modem.
 Demon Dialer tries a brute force password attack
on a found connection.
 Typically: war dialing will find an unsecured
connection.
Scanning: Network Mapping
Ping:
 ping is implemented using the Internet
Control Message Protocol (ICMP) Echo
Request.
 A receiving station answers back to the
sender.
 Used by system administrators to check
status of machines and connections.
Scanning: Network Mapping
Traceroute:
 Pings a system with ICMP echo requests
with varying life spans (= # of hops
allowed).
 A system that receives a package with
expired numbers of hops sends an error
message back to sender.
 Traceroute uses this to find the route to a
given system.
 Useful for System Administration
Scanning: Network Mapping
Cheops:
Network Scanner
(UNIX based)
(Uses traceroute and
other tools to map
a network.)
Cheops et Co. are the
reason that firewalls
intercept pings.
Reconnaissance: Port Scans
Applications on a system use ports to
listen for network traffic or send it out.
 216 ports available, some for known
services such as http (80), ftp, ...
 Port scans send various type of IP
packages to target on different ports.
 Reaction tells them whether the port is
open (an application listens).

Reconnaissance: Nmap
Uses different types of packets to check
for open ports.
 Can tell from the reaction what OS is
running, including patch levels.
 Can run in stealth mode, in which it is not
detected by many firewalls.

Gaining Access
Gain access using application and OS
attacks.
 Gain access using network attack.

Gaining Access through Apps and OS
Stack-Based Overflow Attacks
Stack is the area where function arguments
and return addresses are saved.
 Password Attacks
 Web Application Attacks

Gaining Access:
Web Application Attacks

The URL not only contains the web
address of a site, but also input:
http://www.google.com/search?hl=en&ie=UTF-8&oe=UTF8&q=web+application+attack

A poorly written webpage allows the
viewer to input data in an uncontrolled
fashion. If the webpage contains SQL, the
user might execute SQL commands.
Gaining Access through Network
Attacks: Sniffing
Sniffer: Gathers traffic from a LAN.
 Examples: Snort www.snort.org, Sniffit
reptile.rug.ac.be/~coder/sniffit/sniffit.html
 To gain access to packages, use spoofed
ARP (Address Resolution Protocol) to
reroute traffic.

Gaining Access through Network
Attacks: Sniffing

Sniffing through a hub:

Hub broadcasts all traffic.
Listener
Sender
HUB
Listener
Listener
Listener
Gaining Access through Network
Attacks: Sniffing

Sniffing through a hub:

Switch only forwards to the link with the
correct MAC address.
Listener
Sender
Switch
Listener
Listener
Listener
Gaining Access through Network
Attacks: Sniffing
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Sniffing through a hub:
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MAC flooding:
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Switches store MAC addresses in a cache.
Switches accept MAC advertising.
Attacker sends a flood of MAC advertisings.
Switch’s cache fills up.
Switch moves into promiscuous mode.
Spoofed ARP messages
Gaining Access through Network
Attacks: Sniffing
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Sniffing through a hub:
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Spoofed ARP messages:
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ARP resolves between IP addresses and MAC addresses.
Step 1: Attacker sets up IP Forwarding to the default router
on LAN.
Step 2: Send a faked ARP reply to victims machine to
reroute default router IP to attackers MAC address.
Step 3: Victim sends out a message to the outside world.
This is routed to the default router IP, i.e. to the attackers
machine.
Step 4: Attacker reads traffic.
Step 5: Because of forwarding, packet is forwarded to
actual default router.
Gaining Access through Network
Attacks: Sniffing

Man in the Middle Attack with DSniff:
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Step 1: Send fake DNS response with IP
address for the web site to be attacked to the
victim.
Step 2: Victim connects to website.
Step 3: DNS resolves to the attacker’s
machine, request send there.
Step 4: Attacker’s site receives request, acts
as proxy, forwards it to real website.
Step 5: Real website answers, attackers site
forwards to victim.
…
Gaining Access: Session Hijacking
IP Address Spoofing: Send out IP
packages with false IP addresses.
 If an attacker sits on a link through which
traffic between two sites flows, the
attacker can inject spoofed packages to
“hijack the session”.
 Attacker inserts commands into the
connection.
 Details omitted.

Exploiting and Maintaining Address
After successful intrusion, an attacker
should:
 Use other tools to gain root or
administrator privileges.
 Erase traces (e.g. change log entries).
 Take measures to maintain access.
 Erase security holes so that no-one else
can gain illicit access and do something
stupid to wake up the sys. ad.
Maintaining Access: Trojans

A program with an additional, evil
payload.

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Running MS Word also reinstalls a backdoor.
ps does not display the installed sniffer.
Maintaining Access: Backdoors
Bypass normal security measures.
Example: netcat
 Install
netcat on victim with the
GAPING_SECURITY_HOLE option.
C:\ nc -1 –p 12345 –e cmd.sh
 In the future: connect to port 12345 and
start typing commands.

Maintaining Access: Backdoors
BO2K (Back Orifice 2000) runs in stealth
mode (you cannot discover it by looking at
the processes tab in the TASK MANAGER.
 Otherwise, it is a remote control program
like pcAnyWhere, that allows accessing a
computer over the net.

Maintaining Access: Backdoors

RootKit:
A backdoor built as a Trojan of system
executables such as ipconfig.

Kernel-Level RootKit:
Changes the OS, not only system executables.
Covering Tracks:
Altering logs.
 Create difficult to find files and directories.
 Covert Channels through Networks:
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Loki uses ICMP messages as the carrier.
Use WWW traffic.
Use unused fields in TCP/IP headers.
Hacker Profile
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Internal Hacker
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Disgruntled employee
Contracted employee
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Targets for corporate espionage.
Are not bound by employee policies and procedures.
Indirectly contracted employee
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Perform shared or subcontracted services
Hacker Profile
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External Hacker
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Recreational Hacker
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85% 90% male.
Between 12 and 25.
Highly intelligent low-achiever.
Typically from dysfunctional families.
Professional Hacker
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Hackers for hire.
Electronic warfare, corporate espionage.
“Security Consultants”
Security Consultants
Hacker Profile
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Virus writers1
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Teenagers, College Students, Professionals
Drop out of the scene as adults or have social problems.
Intelligent, educated, male.
Study by Sarah Gordon, IBM, in Beiser, Vince, “Inside the Virus
Writer’s Mind”
Hacker Profile
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Script Kiddy
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Uses scripts of programs written by others to
exploit known vulnerabilities
Goal is bragging rights, defacing web sites
Sweep IP addresses for vulnerability
Typically not explicitly malicious, but can cause
damage inadvertently
Hacker Profile
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Dedicated Hacker
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Does research.
Knows in and outs of OS, system, auditing and
security tools.
Writes or modifies programs and shell scripts
Reads security bulletins (CERT, NIST)
Searches the underground.
Hacker Profile
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Skilled Hacker
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Thorough understanding of system at the level
of Sys Ad or above.
Can read OS source code.
Understands network protocols.
Superhacker
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Does not brag or post.
Can enter or bring down any system.
http://www.securityfocus.com/news/203
Hacker Motives
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Intellectually Motivated
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Educational experimentation
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“Harmless Fun”
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28 year old computer expert diverted 2585 US West
computers to search for a new prime number.
Used 10.63 years of computer time.
Lengthened telephone number lookup to 5 minutes
Almost shut down the Phoenix Service Delivery Center
Web defacing
Wake-up Call
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Free-lance security consultant (still illegal)
Hacker Motives
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Personally motivated
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Disgruntled employee.
Cyber-stalking
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E.g. to show of superiority to someone they feel / are
inferior to.
Danger of escalation to physical attack.
 A 50-year old security guard used the internet to solicit
the rape of a 28-year old woman who rejected him.
 Impersonated her in chat rooms and online bulletins.
 Impersonated rape fantasies.
 At least six man knocked at her door at night offering
to rape her.
 Six years in prison.
Hacker Motives
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Socially motivated
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Cyber-activism
Politically motivated
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Hacking KKK or NAACP websites
Cyber-Terrorism
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Threatens serious disruption of the infrastructure
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Power
Water
Transportation
Communication
1988: Israeli Virus and logic bomb in Israeli government
computers
Cyber-warfare
Hacker Motives
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Financially Motivated
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Personal profit.
 Two Cisco Systems consultants issued almost $8 M
Cisco stock to themselves.
 Accessed a system used to manage stock option
disbursals to find control numbers for forged
authorization forms.
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Damage to the organization.
 British internet provider, Cloud Nine, went out of
business after crippling series of DOS attacks.
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Ego Motivated
Hacker Damage
Releasing Information
 Releasing Software
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By circumventing copying protection.
Through IP theft
Consuming Unused(?) Resources
 Discover and Document Vulnerabilities
 Compromise Systems and Increase their
Vulnerabilities
 Website Vandalism
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