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Ethical Hacking : Why Do Hackers Attack And How ?

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Hackers attack websites and networks for various reasons such as financial gain, espionage, activism, or terrorism. Common attack methods include denial of service attacks to crash systems, spoofing identities to gain unauthorized access, hijacking sessions, exploiting software vulnerabilities like buffer overflows, and cracking passwords. To prevent attacks, network administrators must secure systems from intrusion, monitor for suspicious activity, and keep software updated by patching known vulnerabilities.

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Ethical Hacking (CEH ) Why Security …???? Why Do Hackers Attack …???
• Some of the sites which have been compromised – U.S. Department of Commerce – NASA – CIA – Greenpeace – Motorola – UNICEF – Church of Christ … • Some sites which have been rendered ineffective – Yahoo – Microsoft – Amazon … Why Security?
• Because they can – A large fraction of hacker attacks have been pranks • Financial Gain • Espionage • Venting anger at a company or organization • Terrorism Why do Hackers Attack?
• Active Attacks – Denial of Service – Breaking into a site • Intelligence Gathering • Resource Usage • Deception • Passive Attacks – Sniffing • Passwords • Network Traffic • Sensitive Information – Information Gathering Types of Hacker Attack
• Over the Internet • Over LAN • Locally • Offline • Theft • Deception Modes of Hacker Attack
Definition: An attacker alters his identity so that some one thinks he is some one else – Email, User ID, IP Address, … – Attacker exploits trust relation between user and networked machines to gain access to machines Types of Spoofing: 1. IP Spoofing: 2. Email Spoofing 3. Web Spoofing Spoofing
Definition: Attacker uses IP address of another computer to acquire information or gain access IP Spoofing – Flying-Blind Attack Replies sent back to 10.10.20.30 Spoofed Address 10.10.20.30 Attacker 10.10.50.50 John 10.10.5.5 From Address: 10.10.20.30 To Address: 10.10.5.5 • Attacker changes his own IP address to spoofed address • Attacker can send messages to a machine masquerading as spoofed machine • Attacker can not receive messages from that machine
Definition: Attacker spoofs the address of another machine and inserts itself between the attacked machine and the spoofed machine to intercept replies IP Spoofing – Source Routing Replies sent back to 10.10.20.30 Spoofed Address 10.10.20.30 Attacker 10.10.50.50 John 10.10.5.5 From Address: 10.10.20.30 To Address: 10.10.5.5 • The path a packet may change can vary over time • To ensure that he stays in the loop the attacker uses source routing to ensure that the packet passes through certain nodes on the network Attacker intercepts packets as they go to 10.10.20.30
Definition: Attacker sends messages masquerading as some one else What can be the repercussions? Types of Email Spoofing: 1. Create an account with similar email address – Sanjaygoel@yahoo.com: A message from this account can perplex the students 1. Modify a mail client – Attacker can put in any return address he wants to in the mail he sends 1. Telnet to port 25 – Most mail servers use port 25 for SMTP. Attacker logs on to this port and composes a message for the user. Email Spoofing
• Basic – Attacker registers a web address matching an entity e.g. votebush.com, geproducts.com, gesucks.com • Man-in-the-Middle Attack – Attacker acts as a proxy between the web server and the client – Attacker has to compromise the router or a node through which the relevant traffic flows • URL Rewriting – Attacker redirects web traffic to another site that is controlled by the attacker – Attacker writes his own web site address before the legitimate link • Tracking State – When a user logs on to a site a persistent authentication is maintained – This authentication can be stolen for masquerading as the user Web Spoofing
• Web Site maintains authentication so that the user does not have to authenticate repeatedly • Three types of tracking methods are used: 1. Cookies: Line of text with ID on the users cookie file – Attacker can read the ID from users cookie file 1. URL Session Tracking: An id is appended to all the links in the website web pages. – Attacker can guess or read this id and masquerade as user 1. Hidden Form Elements – ID is hidden in form elements which are not visible to user – Hacker can modify these to masquerade as another user Web Spoofing – Tracking State
Definition: Process of taking over an existing active session Modus Operandi: 1. User makes a connection to the server by authenticating using his user ID and password. 2. After the users authenticate, they have access to the server as long as the session lasts. 3. Hacker takes the user offline by denial of service 4. Hacker gains access to the user by impersonating the user Session Hijacking
• Attacker can – monitor the session – periodically inject commands into session – launch passive and active attacks from the session Session Hijacking Bob telnets to Server Bob authenticates to Server Bob Attacker Server Die! Hi! I am Bob
• Attackers exploit sequence numbers to hijack sessions • Sequence numbers are 32-bit counters used to: – tell receiving machines the correct order of packets – Tell sender which packets are received and which are lost • Receiver and Sender have their own sequence numbers • When two parties communicate the following are needed: – IP addresses – Port Numbers – Sequence Number • IP addresses and port numbers are easily available so once the attacker gets the server to accept his guesses sequence number he can hijack the session. Session Hijacking – How Does it Work?
Definition: Attack through which a person can render a system unusable or significantly slow down the system for legitimate users by overloading the system so that no one else can use it. Types: 1. Crashing the system or network – Send the victim data or packets which will cause system to crash or reboot. 1. Exhausting the resources by flooding the system or network with information – Since all resources are exhausted others are denied access to the resources 1. Distributed DOS attacks are coordinated denial of service attacks involving several people and/or machines to launch attacks Denial of Service (DOS) Attack
Types: 1. Ping of Death 2. SSPing 3. Land 4. Smurf 5. SYN Flood 6. CPU Hog 7. Win Nuke 8. RPC Locator 9. Jolt2 10. Bubonic 11. Microsoft Incomplete TCP/IP Packet Vulnerability 12. HP Openview Node Manager SNMP DOS Vulneability 13. Netscreen Firewall DOS Vulnerability 14. Checkpoint Firewall DOS Vulnerability Denial of Service (DOS) Attack
• This attack takes advantage of the way in which information is stored by computer programs • An attacker tries to store more information on the stack than the size of the buffer How does it work? Buffer Overflow Attacks • Buffer 2 Local Variable 2 Buffer 1 Local Variable 1 Return Pointer Function Call Arguments • Fill Direction Bottom of Memory Top of Memory Normal Stack • Buffer 2 Local Variable 2 Machine Code: execve(/bin/sh) New Pointer to Exec Code Function Call Arguments • Fill Direction Bottom of Memory Top of Memory Smashed Stack Return Pointer Overwritten Buffer 1 Space Overwritten
• Programs which do not do not have a rigorous memory check in the code are vulnerable to this attack • Simple weaknesses can be exploited – If memory allocated for name is 50 characters, someone can break the system by sending a fictitious name of more than 50 characters • Can be used for espionage, denial of service or compromising the integrity of the data Examples – NetMeeting Buffer Overflow – Outlook Buffer Overflow – AOL Instant Messenger Buffer Overflow – SQL Server 2000 Extended Stored Procedure Buffer Overflow Buffer Overflow Attacks
• A hacker can exploit a weak passwords & uncontrolled network modems easily • Steps – Hacker gets the phone number of a company – Hacker runs war dialer program • If original number is 555-5532 he runs all numbers in the 555-55xx range • When modem answers he records the phone number of modem – Hacker now needs a user id and password to enter company network • Companies often have default accounts e.g. temp, anonymous with no password • Often the root account uses company name as the password • For strong passwords password cracking techniques exist Password Attacks
• Password hashed and stored – Salt added to randomize password & stored on system • Password attacks launched to crack encrypted password Password Security Hash Function Hashed Password Salt Compare Password Client Password Server Stored Password Hashed Password Allow/Deny Access
• Find a valid user ID • Create a list of possible passwords • Rank the passwords from high probability to low • Type in each password • If the system allows you in – success ! • If not, try again, being careful not to exceed password lockout (the number of times you can guess a wrong password before the system shuts down and won’t let you try any more) Password Attacks - Process
• Dictionary Attack – Hacker tries all words in dictionary to crack password – 70% of the people use dictionary words as passwords • Brute Force Attack – Try all permutations of the letters & symbols in the alphabet • Hybrid Attack – Words from dictionary and their variations used in attack • Social Engineering – People write passwords in different places – People disclose passwords naively to others • Shoulder Surfing – Hackers slyly watch over peoples shoulders to steal passwords • Dumpster Diving – People dump their trash papers in garbage which may contain information to crack passwords Password Attacks - Types
• Computer Security is a continuous battle – As computer security gets tighter hackers are getting smarter • Very high stakes Conclusions Learn Ethical Hacking At HB Services Call 7550245795 / 9677167119

More Related Content

Ethical Hacking : Why Do Hackers Attack And How ?

  • 1. Ethical Hacking (CEH ) Why Security …???? Why Do Hackers Attack …???
  • 2. • Some of the sites which have been compromised – U.S. Department of Commerce – NASA – CIA – Greenpeace – Motorola – UNICEF – Church of Christ … • Some sites which have been rendered ineffective – Yahoo – Microsoft – Amazon … Why Security?
  • 3. • Because they can – A large fraction of hacker attacks have been pranks • Financial Gain • Espionage • Venting anger at a company or organization • Terrorism Why do Hackers Attack?
  • 4. • Active Attacks – Denial of Service – Breaking into a site • Intelligence Gathering • Resource Usage • Deception • Passive Attacks – Sniffing • Passwords • Network Traffic • Sensitive Information – Information Gathering Types of Hacker Attack
  • 5. • Over the Internet • Over LAN • Locally • Offline • Theft • Deception Modes of Hacker Attack
  • 6. Definition: An attacker alters his identity so that some one thinks he is some one else – Email, User ID, IP Address, … – Attacker exploits trust relation between user and networked machines to gain access to machines Types of Spoofing: 1. IP Spoofing: 2. Email Spoofing 3. Web Spoofing Spoofing
  • 7. Definition: Attacker uses IP address of another computer to acquire information or gain access IP Spoofing – Flying-Blind Attack Replies sent back to 10.10.20.30 Spoofed Address 10.10.20.30 Attacker 10.10.50.50 John 10.10.5.5 From Address: 10.10.20.30 To Address: 10.10.5.5 • Attacker changes his own IP address to spoofed address • Attacker can send messages to a machine masquerading as spoofed machine • Attacker can not receive messages from that machine
  • 8. Definition: Attacker spoofs the address of another machine and inserts itself between the attacked machine and the spoofed machine to intercept replies IP Spoofing – Source Routing Replies sent back to 10.10.20.30 Spoofed Address 10.10.20.30 Attacker 10.10.50.50 John 10.10.5.5 From Address: 10.10.20.30 To Address: 10.10.5.5 • The path a packet may change can vary over time • To ensure that he stays in the loop the attacker uses source routing to ensure that the packet passes through certain nodes on the network Attacker intercepts packets as they go to 10.10.20.30
  • 9. Definition: Attacker sends messages masquerading as some one else What can be the repercussions? Types of Email Spoofing: 1. Create an account with similar email address – Sanjaygoel@yahoo.com: A message from this account can perplex the students 1. Modify a mail client – Attacker can put in any return address he wants to in the mail he sends 1. Telnet to port 25 – Most mail servers use port 25 for SMTP. Attacker logs on to this port and composes a message for the user. Email Spoofing
  • 10. • Basic – Attacker registers a web address matching an entity e.g. votebush.com, geproducts.com, gesucks.com • Man-in-the-Middle Attack – Attacker acts as a proxy between the web server and the client – Attacker has to compromise the router or a node through which the relevant traffic flows • URL Rewriting – Attacker redirects web traffic to another site that is controlled by the attacker – Attacker writes his own web site address before the legitimate link • Tracking State – When a user logs on to a site a persistent authentication is maintained – This authentication can be stolen for masquerading as the user Web Spoofing
  • 11. • Web Site maintains authentication so that the user does not have to authenticate repeatedly • Three types of tracking methods are used: 1. Cookies: Line of text with ID on the users cookie file – Attacker can read the ID from users cookie file 1. URL Session Tracking: An id is appended to all the links in the website web pages. – Attacker can guess or read this id and masquerade as user 1. Hidden Form Elements – ID is hidden in form elements which are not visible to user – Hacker can modify these to masquerade as another user Web Spoofing – Tracking State
  • 12. Definition: Process of taking over an existing active session Modus Operandi: 1. User makes a connection to the server by authenticating using his user ID and password. 2. After the users authenticate, they have access to the server as long as the session lasts. 3. Hacker takes the user offline by denial of service 4. Hacker gains access to the user by impersonating the user Session Hijacking
  • 13. • Attacker can – monitor the session – periodically inject commands into session – launch passive and active attacks from the session Session Hijacking Bob telnets to Server Bob authenticates to Server Bob Attacker Server Die! Hi! I am Bob
  • 14. • Attackers exploit sequence numbers to hijack sessions • Sequence numbers are 32-bit counters used to: – tell receiving machines the correct order of packets – Tell sender which packets are received and which are lost • Receiver and Sender have their own sequence numbers • When two parties communicate the following are needed: – IP addresses – Port Numbers – Sequence Number • IP addresses and port numbers are easily available so once the attacker gets the server to accept his guesses sequence number he can hijack the session. Session Hijacking – How Does it Work?
  • 15. Definition: Attack through which a person can render a system unusable or significantly slow down the system for legitimate users by overloading the system so that no one else can use it. Types: 1. Crashing the system or network – Send the victim data or packets which will cause system to crash or reboot. 1. Exhausting the resources by flooding the system or network with information – Since all resources are exhausted others are denied access to the resources 1. Distributed DOS attacks are coordinated denial of service attacks involving several people and/or machines to launch attacks Denial of Service (DOS) Attack
  • 16. Types: 1. Ping of Death 2. SSPing 3. Land 4. Smurf 5. SYN Flood 6. CPU Hog 7. Win Nuke 8. RPC Locator 9. Jolt2 10. Bubonic 11. Microsoft Incomplete TCP/IP Packet Vulnerability 12. HP Openview Node Manager SNMP DOS Vulneability 13. Netscreen Firewall DOS Vulnerability 14. Checkpoint Firewall DOS Vulnerability Denial of Service (DOS) Attack
  • 17. • This attack takes advantage of the way in which information is stored by computer programs • An attacker tries to store more information on the stack than the size of the buffer How does it work? Buffer Overflow Attacks • Buffer 2 Local Variable 2 Buffer 1 Local Variable 1 Return Pointer Function Call Arguments • Fill Direction Bottom of Memory Top of Memory Normal Stack • Buffer 2 Local Variable 2 Machine Code: execve(/bin/sh) New Pointer to Exec Code Function Call Arguments • Fill Direction Bottom of Memory Top of Memory Smashed Stack Return Pointer Overwritten Buffer 1 Space Overwritten
  • 18. • Programs which do not do not have a rigorous memory check in the code are vulnerable to this attack • Simple weaknesses can be exploited – If memory allocated for name is 50 characters, someone can break the system by sending a fictitious name of more than 50 characters • Can be used for espionage, denial of service or compromising the integrity of the data Examples – NetMeeting Buffer Overflow – Outlook Buffer Overflow – AOL Instant Messenger Buffer Overflow – SQL Server 2000 Extended Stored Procedure Buffer Overflow Buffer Overflow Attacks
  • 19. • A hacker can exploit a weak passwords & uncontrolled network modems easily • Steps – Hacker gets the phone number of a company – Hacker runs war dialer program • If original number is 555-5532 he runs all numbers in the 555-55xx range • When modem answers he records the phone number of modem – Hacker now needs a user id and password to enter company network • Companies often have default accounts e.g. temp, anonymous with no password • Often the root account uses company name as the password • For strong passwords password cracking techniques exist Password Attacks
  • 20. • Password hashed and stored – Salt added to randomize password & stored on system • Password attacks launched to crack encrypted password Password Security Hash Function Hashed Password Salt Compare Password Client Password Server Stored Password Hashed Password Allow/Deny Access
  • 21. • Find a valid user ID • Create a list of possible passwords • Rank the passwords from high probability to low • Type in each password • If the system allows you in – success ! • If not, try again, being careful not to exceed password lockout (the number of times you can guess a wrong password before the system shuts down and won’t let you try any more) Password Attacks - Process
  • 22. • Dictionary Attack – Hacker tries all words in dictionary to crack password – 70% of the people use dictionary words as passwords • Brute Force Attack – Try all permutations of the letters & symbols in the alphabet • Hybrid Attack – Words from dictionary and their variations used in attack • Social Engineering – People write passwords in different places – People disclose passwords naively to others • Shoulder Surfing – Hackers slyly watch over peoples shoulders to steal passwords • Dumpster Diving – People dump their trash papers in garbage which may contain information to crack passwords Password Attacks - Types
  • 23. • Computer Security is a continuous battle – As computer security gets tighter hackers are getting smarter • Very high stakes Conclusions Learn Ethical Hacking At HB Services Call 7550245795 / 9677167119

Editor's Notes

  1. Get some stories about hackings
  2. An active attack involves a deliberate action on the part of the attacker to gain information that he is after. Like trying to telnet to port 25 on a company server to break into the mail server. This is like a burglar trying to pick a lock. This is fairly easy to detect. Passive attacks are mainly information gathering attacks and precede the active attacks.
  3. Get some stories about hackings
  4. 1. Normally users log on to one machine and have access to a number of computers.
  5. 1. Normally users log on to one machine and have access to a number of computers.
  6. 1. Normally users log on to one machine and have access to a number of computers.
  7. Repercussions:
  8. Potential Damages: 1. Change orders placed by the client (Instead of 500 widgets he can make the order 50,000 widgets) 2. Change meeting venues to send people on wild goose chases
  9. Potential Damages: 1. Change orders placed by the client (Instead of 500 widgets he can make the order 50,000 widgets) 2. Change meeting venues to send people on wild goose chases
  10. Session Hijacking allows hackers to bypass the authentication process of the computer and gain access to the machine. After users authenticate and log on to a machine the authentication is valid for as long as the session lasts. After the users authenticate they have
  11. Session Hijacking allows hackers to bypass the authentication process of the computer and gain access to the machine. After users authenticate and log on to a machine the authentication is valid for as long as the session lasts. After the users authenticate they have
  12. Session Hijacking allows hackers to bypass the authentication process of the computer and gain access to the machine. After users authenticate and log on to a machine the authentication is valid for as long as the session lasts. After the users authenticate they have
  13. Session Hijacking allows hackers to bypass the authentication process of the computer and gain access to the machine. After users authenticate and log on to a machine the authentication is valid for as long as the session lasts. After the users authenticate they have
  14. Session Hijacking allows hackers to bypass the authentication process of the computer and gain access to the machine. After users authenticate and log on to a machine the authentication is valid for as long as the session lasts. After the users authenticate they have
  15. Page 245 (Chapter 7 – Hackers Beware by Eric Cole) When a program calls a subroutine, the function variables and the subroutine return address pointers are stored in a logical data structure known as a stack. A stack is a portion of memory that stores information the current program needs. A return pointer contains the address of the point in the program to return to after the subroutine has completed execution. The variable space is filled LIFO I.e. higher address to lower address. When variable space is exceeded the data goes to neighboring variable space. To cause code to be executed an attacker takes advantage of this by precisely tuning the amount and content of data necessary to cause the buffer to over flow and the operating system stack to crash. The data that the attacker sends usually consists of machine specific byte code to execute a command, plus a new address of the return pointer. This address points back into the address space of the stack, causing the program to run the attacker’s instructions when it attempts to return from the subroutine. The attackers code will run at whatever privileges the host code is running. So normally hackers try to use programs which run with root privileges.
  16. Get some stories about hackings
  17. Get some stories about hackings
  18. Get some stories about hackings
  19. Get some stories about hackings
  20. Get some stories about hackings