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COEN 252

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

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COEN 252

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  1. COEN 252 Security Threats

  2. 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

  3. Hacking • Targeted Attacks • Theft of information • Incapacitation of an organization to fulfill its purpose by destroying / impeding its use of computing resources

  4. Hacking Phases of a Targeted Attack • Reconnaissance • Scanning • Gaining Access • Expanding Access • Covering Tracks

  5. 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

  6. 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, …

  7. 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

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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).

  13. 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.

  14. 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

  15. 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, …

  16. 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.

  17. Software Vulnerabilities • Attacker needs • to control the environment of the application • or craft input in order to trigger a vulnerability.

  18. 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

  19. 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

  20. 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)

  21. Software Vulnerabilities • Use of magic names • Instance of security by obfuscation • Magic URL • Hidden Form Fields

  22. 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

  23. 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.

  24. 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

  25. 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.

  26. 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. • …

  27. 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.

  28. 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.

  29. Maintaining Access: Trojans • A program with an additional, evil payload. • Running MS Word also reinstalls a backdoor. • ps does not display the installed sniffer.

  30. 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.

  31. 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.

  32. 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.

  33. 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

  34. 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

  35. 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

  36. 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”

  37. 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

  38. 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.

  39. 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

  40. 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)

  41. 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.

  42. 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

  43. 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

  44. 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

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