coen 252 security threats. hacking untargeted attacks motivation is fun (i can do it) prevalent...
TRANSCRIPT
COEN 252
Security Threats
Hacking Untargeted attacks
Motivation is Fun (I can do it)
prevalent until ~2000 Financial Gain
Selling access to compute resources Creation of botnets for spamming, computation
(distributed decryption, phishing, pharming …) Selling data
Credit Card Information E-mails …
Targeted Denial of Service Attacks Cloud Nine, a British ISP failed after suffering attacks
Cyber-warfare, terrorism
Hacking
Targeted Attacks Theft of information Incapacitation of an organization to
fulfill its purpose by destroying / impeding its use of computing resources
Hacking
Phases of a Targeted Attack
Reconnaissance Scanning Gaining Access Expanding Access Covering Tracks
Reconnaissance Social Engineering
Incite a human to act imprudently, furthering the goals of the attacker:
“I cannot access my email. What do I do?” Countermeasures:
Identify security issues Develop policies
Need to prevent leakage of information Need buy-in by users and agents Need to maintain user-friendliness of IT
Physical Reconnaissance Dumpster Diving
Especially bountiful when people move Installation of scanning devices
Reconnaissance Finding publicly available information
Contact information of internet registration WhoIs, ARIN, RIPE, …
Internal documents made publicly available: Use search engines Check Internet Archive, … Identify naming conventions and guess file names Scrutinize publications
A word document might contain the revision history with old versions of file
A PDF file had confidential information obscured by a black box, that could be removed
… Email, Usenet, Blog postings that identify names of internal
machines, …
Reconnaissance: Scanning
Once we have a target, we need to get to know it better.
Methods: War Dialing (to find out modem access) War Driving Network Mapping
Largely obsolete due to better firewall rules Vulnerability Scanning
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. Xmas tree, NULL, Syn, … Scans
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.
Reconnaissance Prevention Firewalls can make it very difficult to
scan from the outside. Drop scan packets.
Patched OS do not have idiosyncratic behavior that allows OS determination.
IDS can detect internal scans and warn against them.
Example: Detect traceroute by not allowing in packets with very small TDL values
Gaining Access
Fault in Policy Weak or no authentication,
unwarranted trust relationships, … Fault in Implementation
Typical triggered by intentionally malformed input
Extension of a security breach Sniffing malware, …
Security Policy, Software defects, flaws, vulnerabilities
A Security Policy is a set of rules and practices that specify or regulate how a system or organization provides security services to protect sensitive and critical system resources [Internet Society 00].
Software Defects: A software defect is the encoding of a human error into the
software, including omissions. Security Flaw:
A security flaw is a software defect that poses a potential security risk.
Eliminating software defects eliminate security flaws. Vulnerability
set of conditions that allows an attacker to violate an explicit or implicit security policy.
Not all security flaws lead to vulnerabilities. Not all vulnerabilities are based on a security flaw.
Software Vulnerabilities
Attacker needs to control the environment of the
application or craft input in order to trigger a vulnerability.
Software Vulnerabilities In a typical environment, attacker needs to be
able to set a single value at a single address in order to execute arbitrary code.
Typical Targets Global Offset Table in Unix
Used to link to library functions .dtors
Used by gcc to link to destructors that run at termination of program
Virtual Function Tables Exception Handling Table in Windows
Software Vulnerabilities Typical Vulnerabilities
Buffer Overruns: Input string is stored on a buffer, but buffer is too small Input located outside of buffer has overwritten data Stack based buffer overflow: Overwrite the return address of a
function Format String Vulnerability: (Specific to C)
Arises by not specifying a format string The %n construct allows attacker to control a random memory
location Integer Overflow Race Conditions
Especially when accessing files
Software Vulnerabilities Typical Vulnerabilities
Injection Attacks Input (e.g. user input to web server) is used to generate
arguments for a command to be executed: Command Injection
Input (e.g. user input to web server) is used to generate arguments for a sql query to be executed and displayed: SQL Injection
Name Resolution Attacks Different modules use different ways to canonicalize /
resolve names of resources such as files HFS2 file names are not case sensitive, but Apache
configuration is Homonyms (e.g. kyrillic vs. regular o)
Software Vulnerabilities
Use of magic names Instance of security by obfuscation
Magic URL Hidden Form Fields
Software Vulnerabilities False amount of security information
results in poor usability Too many warnings: Users are confused and
trained to ignore warnings Too few warnings: Users are not made
aware of risks Bad networking protocols
Unauthenticated key exchange Trusting network name resolution
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: MAC flooding:
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
Sniffing through a hub: Spoofed ARP messages:
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: 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:
Attack privileged programs 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. 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:
Loki uses ICMP messages as the carrier. Use WWW traffic. Use unused fields in TCP/IP headers.
Use antiforensics Change registry values to delete traces of
installed programs Change Date-Time stamps
Hacker Profile
Internal Hacker Disgruntled employee Contracted employee
Targets for corporate espionage. Are not bound by employee policies and
procedures. Indirectly contracted employee
Perform shared or subcontracted services
Hacker Profile External Hacker
Recreational Hacker 85% 90% male. Between 12 and 25. Highly intelligent low-achiever. Typically from dysfunctional families.
Professional Hacker Hackers for hire. Electronic warfare, corporate espionage. So-called “Security Consultants” who look for blackmail
or exploit for hire Security Consultants
Hacker Profile Virus writers1
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
Script Kiddy 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
Dedicated Hacker 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 Skilled Hacker
Thorough understanding of system at the level of Sys Ad or above.
Can read OS source code. Understands network protocols.
Superhacker Does not brag or post. Can enter or bring down any system.
http://www.securityfocus.com/news/203
Hacker Motives Intellectually Motivated
Educational experimentation 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
“Harmless Fun” Web defacing
Wake-up Call Free-lance security consultant (still illegal)
Hacker Motives Personally motivated
Disgruntled employee. Cyber-stalking
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 Socially motivated
Cyber-activism Politically motivated
Hacking KKK or NAACP websites Cyber-Terrorism
Threatens serious disruption of the infrastructure Power Water Transportation Communication
1988: Israeli Virus and logic bomb in Israeli government computers
Cyber-warfare
Hacker Motives Financially Motivated
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.
Damage to the organization. British internet provider, Cloud Nine, went out of
business after crippling series of DOS attacks.
Ego Motivated
Hacking Damage Releasing Information Releasing Software
By circumventing copying protection. Through IP theft
Consuming Unused(?) Resources Discover and Document Vulnerabilities Compromise Systems and Increase their
Vulnerabilities Website Vandalism