DOCSLIB.ORG

Ping of Death Attacks

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Ping of Death Attacks Network Security(CP33925) DoS and DDoS 부산대학교 공과대학 정보컴퓨터공학부 What we’ll learn today … DoS Attack DDoS Attack DoS and DDoS attack countermeasures 2 Understanding DoS attacks DoS (Denial of Service) . An attack that provides information beyond the ability of an attacking target to accept it and then, prevents an attacking target from operating normally beyond the capacity of the user or network DoS Attack Features . Destruction: Disks, Data, System Destruction . System resource depletion: Heavy load due to excessive use of CPU, memory, disk . Network resource depletion: Depletion of network bandwidth with garbage data 3 Ping of Death Attack (1/6) Ping of Death Attack . Use ping to make ICMP packets much larger than normal . Large packets are routed through the network and are broken into very small pieces while reaching the attacking network . The attack target should process much more fragmented packets, so it takes much more load than normal ping Why to segment a packet and deliver it? . Routing does not go through the networks with the same characteristics when forwarding packets • If the maximum packet size for each network is different and the maximum packet size is small, then the data will be divided smaller . Packets once divided do not grow again • To increase the packet, it is necessary to store the packet and reassemble the packet data that comes in next time, which causes a load which is fatal to the performance of the router. 4 Ping of Death Attack (2/6) Packet Segmentation Data Data Data Header FCS 1/3 2/3 3/3 Data Data Data Header FCS Header FCS Header FCS 1/3 1/3 1/3 . Set the maximum length of ICMP packets to 65,500 bytes . When you ping the network with a maximum size of 65,500 bytes, the packet is split into segments . If the maximum transmissionable length of a network through a packet is 100 bytes, then one packet is divided into 655 number of packets 5 Ping of Death Attack (3/6) Practice Environment . Attacker system: Ubuntu desktop 14 . Attack target system: Windows server 2012 . Need hping3, Wireshark Procedure . Installing hping3 (sudo) apt- get install hping3 . Performing Ping of Death Attacks 6 Ping of Death Attack (4/6) Procedure . Analyzing Ping of Death Attacks • Capture a packet sent from Ubuntu desktop 14 (attacker) to Windows Server 2012 (attack target) using Wireshark 7 Ping of Death Attack (5/6) Procedure . Analyzing Ping of Death Attacks • Confirm details of the number 724 packet at Windows Server 2012 using Wireshark 8 Ping of Death Attack (6/6) Security Countermeasures . Ignore ICMP packets over a certain number of incoming iterations . The most common countermeasures are patches 9 SYN Flooding (1/7) SYN Flooding (flooding) . To prevent other users from being offered services by mimicking as clients that do not exist in accessible space limited by server Understanding SYN Flooding Attacks ① The attacker sends a large number of SYN packets to the server ② The server sends a SYN / ACK packet for each received SYN packet to each client ③ The server does not receive an ACK packet for the SYN/ACK packet it sent ④ The server waits for the connection of the session and the attack succeeds . Waiting for an ACK packet in the 'SYN Received' state Server Max. No. of Clients IIS Server 5.0 100,000 Apache Server 150 FTP, Telnet Server 10 100 SYN Flooding (2/7) Practice Environment . Attacker system: Ubuntu desktop 14 . Attack target system: Windows server 2012 . Need hping3 Procedure . Getting started with Web services • Install IIS on the victim machine 11 SYN Flooding (3/7) Procedure . Performing SYN Flooding attacks • Using hping3, a lot of packets are sent in a very short time to perform SYN flooding attack easily hping3 --rand-source 192.168.0.100 -p 80 -S -p 80: Packet transmission for port 80 -S: send only SYN of TCP packets 12 SYN Flooding (4/7) Procedure . Identifying packets of SYN flooding attacks • Capture packets sent by hping3 to the victim machine using Wireshark 13 SYN Flooding (5/7) Procedure . Identifying attacks • Make sure you are being attacked by using netstat, which is used to see information about the currently connected session netstat -an 14 SYN Flooding (6/7) Procedure . Identifying attacks • If multiple IPs are in SYN_RECV state, normal connection to Web server is not possible 15 SYN Flooding (7/7) SYN Flooding Security Countermeasures . Installing System Patches . Install Intrusion Detection System (IDS) or Intrusion Prevention System (IPS) . If it recognizes an attack that sends the same type of packet in a short time, it prohibits the connection of the ① When receiving a SYN packet from a client, corresponding IP address range or put a Syn_Cookie containing simple prohibits the connection from the authentication information in the sequence value and close the session firewall or router. ② When the client sends an ACK with a value . By using encryption technology in that contains Syn_Cookie, the server SYN+ACK packet sent from server to reopens the session and starts communicating client and sending it to client, use Wait time per server after receiving SYN Syn_Cookie to generate a sequence Server Waiting Time number containing authentication Windows NT/2K 255 Sec information Unix/Linux 60 sec 16 Apache 300 sec (/etc/httpd.conf) Boink, Bonk, Teardrop (1/4) Boink, Bonk, Teardrop . Boink, Bonk, and Teardrop trick sequence numbers to overload the system's packet retransmission and reassembly Understanding Boink, Bonk, Teardrop . Bonk: After sending the first packet with the sequence number 1, the sequence numbers of the second packet and the third packet are set to 1 . Boink: After sending the first packet with the sequence number 1, number 101 for the second packet, number 201 for the third packet, etc., and send the patterned sequence number in the middle . Teardrop: Shuffle the sequence number to make it more complicated by creating overlapping and free space, changing the sequence number constantly → The sequence numbers that are not matched at all cause confusion for the attacker to combine the packetized data and thus, the CPU is overloaded. 17 Boink, Bonk, Teardrop (2/4) Teardrop Attack Packet Number Seq. Number of Normal Packet Seq. Number of Attack Packet 1 1-101 1-101 2 101-201 811-181 3 201-301 221-321 4 301-401 2511-3511 18 Boink, Bonk, Teardrop (3/4) Practice Environemnt . Attacker system: Ubuntu desktop 14 . Attack target system: Windows server 2012 . Need hping3 Procedure . Perform Teardrop Attacks hping3 -a 200.200.200.200 192.168.0.1 --id 3200 --seqnum -p 21 -d 320 --flood --id 3200: TCP packet's ID value, if the same ID value, considered TCP packets of the same session --seqnum: randomly set the sequence number of the TCP packet -d 320: set the length of the packet to 320 bytes 19 Boink, Bonk, Teardrop (4/4) Procedure . Analyze packets of Teardrop attack • It can be confirmed that the sequence number of the TCP packet is arbitrarily generated and transmitted. 20 Land Attack (1/2) Land Attack . Putting the system in a bad state . When sending a packet, make the packet whose source IP address and destination IP address are the same • The value of the malformed IP address must be the IP address of the victim . Land attack method occupies the number of concurrent users and thus, increases CPU load Land security measures . In a router or firewall, prevent the packet whose source IP address is the same as the internal IP address Practice Environment . Attacker system: Ubuntu desktop 14 . Attack target system: windows server 2012 . Need hping3 21 Land Attack (2/2) Procedure . Run Land attack . Analyze packets of Land attack • Capture packets sent by hping3 using Wireshark 22 Smurf & Fraggle Attack (1/3) Smurf Attack . When the worm attacks the network, it uses ICMP packets . Routers do not support broadcasts by default, so when you broadcast to other networks, you will have a direct broadcast . When the destination IP address value is set to 255.255.255.255 and the packet is sent, the router is prevented from going out to the external network, so that it operates only in the internal LAN . The network that receives the ICMP request sends the ICMP Reply back to the forged IP address of the ICMP Request packet . The victim receives a large number of ICMP replies, and numerous packets, such as Ping of Death, overload the system Smurf Security Countermeasures . Prevent Direct Broadcast 23 Smurf & Fraggle Attack (2/3) Practice Environment . Attacker system: Ubuntu desktop 14 . Agent system: Ubuntu desktop 16 . Attack target system: windows server 2012 . Need hping3 Procedure . Run Smurf attack 24 Smurf & Fraggle Attack (3/3) Procedure . Analyzing packets of Smurf attacks • Check results captured with TCP Dump and Wireshark 25 7-layer DoS Attack (1/3) 7-layer DoS attack . The recent DoS attacks are aimed at web applications, etc . Difference between 3, 4-layer DoS attack and 7-layer DoS attack 3, 4-Layer DoS Attack 7-Layer DoS Attack • Bandwidth Depletion Attack • Server resource depletion attack Main Attack • Session depletion attack Main protocol • TCP, UDP, ICMP • HTTP, SMTP, FTP, VoIP etc. • Attacks by generating a large amount of flooding traffic • Attacks using normal traffic • Spoofed IP has a high percentage of attacks using • Attacks using a small amount of traffic Characteristics unusual traffic • Exploiting vulnerability of specific application • Can be defended through security equipment Key features of 7-layer attack . Normal TCP / UDP connection-based attack • It is difficult to detect because it is difficult to distinguish from normal user's traffic with attack traffic after requesting access using normal IP instead of modulated IP .
Load more

Recommended publications
  • Many Slides Borrowed from Ben Zhao, Christo Wilson, & Others
    12. Network Attacks Blase Ur and David Cash (many slides borrowed from Ben Zhao, Christo Wilson, & others) February 7th, 2020 CMSC 23200 / 33250 Network threat model • Network scanning • Attacks on confidentiality (e.g., eavesdropping) • Attacks on integrity (e.g., spoofing, packet injection) • Attacks on availability (e.g., denial of service (DoS)) Scanning and observing networks Network Scanning: Ping • Essential, low-level network utility • Sends a “ping” ICMP message to a host on the internet $ ping 66.66.0.255 PING 66.66.0.255 (66.66.0.255) 56(84) bytes of data. 64 bytes from 66.66.0.255: icmp_seq=1 ttl=58 time=41.2 ms • Destination host is supposed to respond with a “pong” – Indicating that it can receive packets • By default, ping messages are 56 bytes long (+ some header bytes) – Maximum size 65535 bytes • What if you send a ping that is >65535 bytes long? Ping of Death • $ ping –s 65535 66.66.0.255 – Attack identified in 1997 – IPv6 version identified/fixed in 2013 Network Scanning: Traceroute • traceroute — hops between me and host – Sends repeated ICMP reqs w/ increasing TTL Port Scanning • What services are running on a server? Nmap • 5 seconds to scan a single machine!! SYN scan Only send SYN Responses: • SYN-ACK — port open • RST — port closed • Nothing — filtered (e.g., firewall) Port Scanning on Steroids • How do you speed up scans for all IPv4? – Don’t wait for responses; pipeline – Parallelize: divide & conquer IPv4 ranges – Randomize permutations w/o collisions • Result: the zmap tool – Scan all of IPv4 in 45mins (w/ GigE cxn) – IPv4 in 5 mins w/ 10GigE Eavesdropping Tools: Wireshark, tcpdump, Bro, … Steps: 1.
    [Show full text]
  • WHITE PAPER Distributed Denial of Service
    WHITE PAPER Distributed Denial of Service DDoS Attack Testing and Verification Solutions OVERVIEW “Xena recreates complex First seen around 2000, Distributed Denial-of-Service (DDoS) attacks are a serious traffic so client and server threat to businesses around the world. Attackers use multiple hosts to swamp targets with bogus traffic, paralyzing the network and potentially costing the victims millions of communicate in exactly dollars. There are many security systems for preventing DDoS attacks – and they all need to be thoroughly tested and verified prior to being activated. the same order as the Xena offers a complete test solution for DDoS mitigation and network security with captured traffic to ensure high-performance products and ample features. Going beyond generating DDoS traffic, Xena’s solutions can help companies test their security products and operators test realistic network scenarios networks and detect flaws, thereby ensuring business continuity and preserve business for the DUT”. integrity. WHITE PAPER Xena Networks – Global Price/Performance Leaders in Gigabit Ethernet Testing – www.xenanetworks.com Distributed Denial of Service DDoS Attack Testing and Verification Solutions Contents INTRODUCTION ................................................................................................................... 3 DDOS Attacks and Business Disruption ........................................................................... 4 Understanding Different DDoS Attacks ..........................................................................
    [Show full text]
  • DNS Threats November, 2015
    DNS Threats November, 2015 This document contains brief descriptions of a number of potential DNS threats. Direct DNS amplification Direct DNS amplification attacks are aimed at congesting DNS server outbound bandwidth. They start by sending a large number of DNS queries, specially crafted so that they result in a very large response that can reach up to 70 times the size of the request. Since DNS relies on the User Datagram Protocol (UDP), the attacker can use a small volume of outbound traffic to cause the DNS server to generate a much larger volume, resulting in congestion of the DNS server’s upload and eventually a denial of service (DoS). Reflection Reflection attacks use a third-party DNS server (typically an open recursive name server) in the Internet to propagate a DoS or DDoS attack by sending queries to the recursive server. Recursive servers will process queries from any IP address, and they return responses. The attack spoofs the DNS queries it sends by including the victim’s IP address as the source IP in the query, so that the query has the victim’s server information rather than the attacker’s. So when the recursive name server receives the requests, it sends all the responses to the victim’s IP address. A high volume of such “reflected” traffic can bring down the victim’s site. Distributed reflection DoS Distributed reflection DoS (DrDoS) attacks combine reflection with amplification that significantly increases the size of the response to the initial queries—and the likelihood that the victim’s server will be overwhelmed.
    [Show full text]
  • Cyber Attacks Explained: Dos and Ddos
    CYBER ATTACKS EXPLAINED: DOS AND DDOS With this article, we begin a new series on the major kinds of cyber attacks that weaken the IT security infrastructure within organisations. With the rapid spread of Internet technologies and applications, the number of those seeking to break into systems is also increasing — usually to gain fame, money, or to damage the target’s reputation. The first to be covered in this series is the Denial of Service attack (DoS) and the distributed version (DDoS). We will learn how these attacks work technically, and discuss ways to stop them at the network entry point. The fundamental technique behind a DoS attack is to make the target system busy. In a computer server, when a network packet is being received, all components (right from the network interface card or NIC to the application running under the OS) are participating to ensure successful delivery of that packet. The NIC must monitor the Ethernet frames meant for it, align data and pass it to the network card driver, which then adds its own intelligence and passes it to the OS, which takes it to the application. Each component involved can exhibit some form of vulnerability, and DoS attacks are devised to exploit one or more of these, to penetrate into the system. Let’s now understand the basics of the TCP/IP protocol, which uses a handshake between the sender and receiver. Figure 1 shows how a healthy TCP handshake takes place, and how a SYN flood attack compares with it. Figure 1: A healthy TCP handshake When the sender wants to communicate, it sends a SYN packet with its own IP address as the source, and the receiver’s IP address as the destination.
    [Show full text]
  • (DOS) Testing Ixchariot
    TEST PLAN Denial of Service (DOS) Testing IxChariot www.ixiacom.com 915-6681-01, 2005 Contents Overview of Denial of Service functionality in IxChariot..................................3 A brief outline of the DoS attack types supported in IxChariot...................... 4 Test Case 1: Ping Attack on Oracle Traffic........................................................5 Test Case : VoIP and TCP SYN Attacks...........................................................8 Copyright © 2005 Ixia. All rights reserved. The information in this document is furnished for Ixia informational use only, is subject to change 6601 W. Agoura Road without notice, and should not be construed as a commitment by Ixia. Ixia assumes no Calabasas, CA 9130 responsibility or liability for any errors or Phone: (818) 871-1800 inaccuracies that may appear in this document. Ixia and the Ixia logo are trademarks of Ixia. All Fax: (818) 871-1805 other companies, product names, and logos are Email: [email protected] trademarks or registered trademarks of their respective holders. Internet: www.ixiacom.com Copyright © Ixia, 005 Denial of Service (DOS) Testing: Sample Test Plans Denial of Service (DOS) Testing: Sample Test Plans Denial of Service (DoS) attacks are a reality for most organizations with connections to the public Internet. In order to protect yourselves from the potential hazards of network hackers and malicious coders, a set of devices and software- based tools such as DUTs, intrusion detection systems (IDS), remote access solutions (VPN) and sophisticated routers and L4-7 application switches have been developed to effectively block malicious traffic and protect the organization’s data and information infrastructure. Leveraging the advanced functionality of Ixia hardware, IxChariot is now capable of generating line-rate traffic that emulates common DoS attack types while at the same time generating and measuring the performance of application traffic (VoIP, Internet, enterprise) that is being sent over the network.
    [Show full text]
  • Dos Attack Prevention Using Rule-Based Sniffing Technique and Firewall in Cloud Computing
    125 E3S W eb of C onferences , 21004 (2019) https://doi.org/10.1051/e3sconf/201912521004 ICENIS 2019 DoS Attack Prevention Using Rule-Based Sniffing Technique and Firewall in Cloud Computing Kagiraneza Alexis Fidele1,2*, and Agus Hartanto2 1 Data Entry and Update Taxpayer’s Registry in Rwanda Revenue Authority (RRA) Kigali-Rwanda 2 Master of Information System, School of Postgraduate Studies Diponegoro University, Semarang – Indonesia Abstract. Nowadays, we are entering an era where the internet has become a necessary infrastructure and support that can be applied as a means of regular communication and data service. In these services, cloud- based on servers has an essential role as it can serve numerous types of devices that are interconnected with several protocols. Unfortunately, internet cloud servers become the main target of attacks such as Denial of Service (DoS), Distributed Denial of Service (DDoS). These attacks have illegal access that could interfere in service functions. Sniffing techniques are typically practiced by hackers and crackers to tap data that passes through the internet network. In this paper, sniffing technique aims to identify packets that are moving across the network. This technique will distinguish packet on the routers or bridges through a sniffer tool known as snort connected to a database containing the attack pattern. If the sniffing system encounters strange patterns and recognizes them as attacks, it will notify to the firewall to separate the attacker's original Internet Protocol (IP) address. Then, communication from the attacker's host to the target will be discontinued. Consequently, the identified attack activity will stop working, and the service will proceed to run.
    [Show full text]
  • ASF Series Ddos Mitigation Datasheet
    ASF Application DDoS Mitigation DATASEET ASF Series Application Security Firewall provides enterprise-grade application DDoS (Distributed Denial of Service) mitigation solution, which helps defend critical business applications in the enterprise data center from DDoS attacks and other threats. Array Networks ASF Series employ the sophisticated 64-bit SpeedCore™ multi-core processing architecture, providing comprehensive and accurate DoS andDDoSattack detection and mitigation for business-critical applications. The ASF Series provide granularattack mitigation controland improve attack detectionaccuracy and minimize false positives with the traffic baseline learning feature, dynamic refreshingof defense profile based on the learned traffic baseline, and the client source verification function. Product Function Description Combination of Detection and Cleaning ASF Series provides a high-performance DDoS engine, which can accurately detect and identify Layer 3 to Layer 7 DDoS attacks and DoS attacks with the help of session tracking and source verification mechanisms. After detecting DDoS attacks, ASF Series will generate and execute automatic blacklist to quickly clean the malicious traffic in the mixed traffic for the defense objects. In addition, ASF Series allows attack detection and traffic cleaning to be deployed together or separately. Enterprise-grade DDoS Mitigation ASF Series provide Layer 3 to Layer 7 DDoS mitigation, capable of mitigating volumetric DDoS attacks, protocol-based DDoS attacks, and application layer attacks with latency of microseconds. ASF Series supports providing granular and unique DDoS mitigation for different applications using DDoS profiles. Once defense objects are created, automatic DDoS profiles will provide the default DDoS mitigation for them. The traffic baseline learning function then allows the appliance to learn the traffic baseline of the applications and thus dynamic refresh the defense parameters for the automatic profiles.
    [Show full text]
  • Junos® OS Attack Detection and Prevention User Guide for Security Devices Copyright © 2021 Juniper Networks, Inc
    Junos® OS Attack Detection and Prevention User Guide for Security Devices Published 2021-09-22 ii Juniper Networks, Inc. 1133 Innovation Way Sunnyvale, California 94089 USA 408-745-2000 www.juniper.net Juniper Networks, the Juniper Networks logo, Juniper, and Junos are registered trademarks of Juniper Networks, Inc. in the United States and other countries. All other trademarks, service marks, registered marks, or registered service marks are the property of their respective owners. Juniper Networks assumes no responsibility for any inaccuracies in this document. Juniper Networks reserves the right to change, modify, transfer, or otherwise revise this publication without notice. Junos® OS Attack Detection and Prevention User Guide for Security Devices Copyright © 2021 Juniper Networks, Inc. All rights reserved. The information in this document is current as of the date on the title page. YEAR 2000 NOTICE Juniper Networks hardware and software products are Year 2000 compliant. Junos OS has no known time-related limitations through the year 2038. However, the NTP application is known to have some difficulty in the year 2036. END USER LICENSE AGREEMENT The Juniper Networks product that is the subject of this technical documentation consists of (or is intended for use with) Juniper Networks software. Use of such software is subject to the terms and conditions of the End User License Agreement ("EULA") posted at https://support.juniper.net/support/eula/. By downloading, installing or using such software, you agree to the terms and conditions
    [Show full text]
  • Jnxjsscreenmontable
    jnxJsScreenMonTable The jnxJsScreenMonTable, whose object ID is {jjnxJsScreenObjects 1}, collects the screen attributes that monitor the various attacks to enable the Juniper Networks Security Firewall to provide deep inspection (DI) protection on each of the security device's physical interfaces. These attributes are listed in jnxJsLoadedCaCertTable. The screen options can be enabled at a security zone bounded to an interface or interfaces. When these options apply to traffic reaching the security device through interfaces (via a zone), they offer protection against a malicious information gathering probe or an attack to compromise, disable, or harm a network or network resources. Table 1: jnxJsScreenMonTable Object Object ID Description jnxJsScreenMonEntry jnxJsScreenMonTable The screen option monitoring statistics entry. Each entry is uniquely 1 identified by the zone name. The data is collected on a per zone basis. There can be multiple interfaces bound to a particular zone. Hence, the statistics are aggregated across the interfaces on a per zone basis. Sequence of parameters: ■ jnxJsScreenZoneName ■ jnxJsScreenNumOfIf ■ jnxJsScreenMonSynAttk ■ jnxJsScreenMonTearDrop ■ jnxJsScreenMonSrcRoute ■ jnxJsScreenMonPingDeath ■ jnxJsScreenMonAddrSpoof ■ jnxJsScreenMonLand ■ jnxJsScreenMonIcmpFlood ■ jnxJsScreenMonUdpFlood ■ jnxJsScreenMonWinnuke ■ jnxJsScreenMonPortScan ■ jnxJsScreenMonIpSweep ■ jnxJsScreenMonSynFrag ■ jnxJsScreenMonTcpNoFlag ■ jnxJsScreenMonIpUnknownProt ■ jnxJsScreenMonIpOptBad ■ jnxJsScreenMonIpOptRecRt—Record route option
    [Show full text]
  • Musings RIK FARROWOPINION
    Musings RIK FARROWOPINION Rik is the editor of ;login:. While I was at LISA ’11, I ran into an old friend, Paul Ebersman . Paul was one of [email protected] the first employees at UUNET, and every time I ran into Paul, usually at a USENIX conference, he would tell me how the UUNET office had grown onto another floor of a building . Eventually, UUNETs growth was taking over entire buildings . Paul would also tell me how fast the Internet was growing, with traffic doubling every few months . UUNET was the fastest-growing ISP in the 1990s [1] and was founded with help from USENIX . These days, Paul is working for a company (Infoblox) that makes server appliances, and his own focus is on IPv6 . Paul’s article about issues with making the transition to IPv6 appears in this issue . During our conversations at LISA, I asked Paul about security and IPv6, and Paul said, “It’s like 1994 all over again ”. What Paul meant was that back in the mid-’90s, organizations were beginning to use the Internet without having more than the vaguest notion of security . Also, most IPv4 software stacks were largely untested, leading to root compromises and various denial-of-service (DoS) attacks, such as the Ping of Death [2] . In many ways, as the momentum to enable IPv6 on Internet- facing Web sites rolls onward, we will be facing another moment where most people will not be familiar with the new security issues that come with using a new network protocol . Just the Same Some things won’t be any different: there are still 65535 TCP and 65535 UDP ports in IPv6, just as in IPv4 .
    [Show full text]
  • TCP/IP Security Topics
    CIT 480: Securing Computer Systems TCP/IP Security Topics 1. Internet Protocol (IP) 2. IP Spoofing and Other Vulnerabilities 3. ICMP 4. Transmission Control Protocol (TCP) 5. TCP Session Hijacking 6. UDP Internet Protocol (IP) Connectionless – Packets may be lost, reordered, – Each packet is transported corrupted, or duplicated independently from other IP packets packets – Encapsulate TCP and UDP Unreliable packets – Delivery on a best effort basis – Encapsulated into link-layer – No acknowledgments frames Data link frame IP packet TCP or UDP packet IP Addresses 32-bit integers that identify machine on net Dotted decimal notation: ii.jj.kk.ll DNS translates names to IP addresses 172 . 16 . 254 . 1 10101100 00010000 11111110 00000001 1 byte 32 bits = 4 bytes IPv6 addresses are 128-bit integers written like 2001:0db8:0000:0000:0000:ff00:0042:8329 Network Address Translation Uses public IP addr to represent private IP. – Translates source IP in outgoing packets. – Translates dest IP in incoming packets. – Router keeps table of translations. IP Address Geolocation • ISPs get blocks of IP addresses from ARIN. • ARIN database records where IP addresses are. • Application layer and time data may help reveal details. Check http://www.findmyip.org/ for your location. IP Header IP Routing A router bridges two or more networks – Operates at the network layer. – Maintains tables to forward packets to the appropriate network. – Forwarding decisions based solely on the destination address. Routing table – Maps ranges of IP addresses to LANs or other gateway routers. IP Routing Same IP address at each hop used to route data packet. New MAC address at each hop IP Vulnerabilities 1.
    [Show full text]
  • Towards Run-Time Protocol Anomaly Detection and Verification
    TOWARDS RUN-TIME PROTOCOL ANOMALY DETECTION AND VERIFICATION InSeon Yoo and Ulrich Ultes-Nitsche Department of Computer Science, University of Fribourg, Chemin du Musee 3, Fribourg, CH1700, Switzerland. Keywords: Run-time Protocol Verification, Protocol Anomaly Detection, SDL, EFSM/CEFSM Abstract: `How to verify incoming packets whether they follow standards or not?' and `How to detect protocol anomalies in real-time?', we seek to answer these questions. In order to solve these questions, we have designed a packet verifier with packet inspection and sanity check. In this work, we specify TCP transaction behaviours declaratively in a high-level language called Specification and Description Language (SDL). This specification will be then compiled into an inspection engine program for oberving packets. In addition, the SanityChecker covers protocol header anomalies. 1 INTRODUCTION 2 EXAMPLE CASES OF PROTOCOL ANOMALIES Protocols are created with specifications, known as RFCs, to dictate proper use and communication. An 2.1 Ping of Death anomaly is defined as something different, abnormal, peculiar, or not easily classified. Protocol anomaly Attackers sends a fragmented PING request that ex- refers to all exceptions related to protocol format and ceeds the maximum IP packet size(64KB), causing protocol behaviour with respect to common practice vulnerable systems to crash. The idea behind the Ping on the Internet and standard specifications. This in- of Death and similar attacks is that the user sends a cludes network and transport layer protocol anoma- packet that is malformed in such a way that the target lies in layer 3 and layer 4 and application layer proto- system will not know how to handle the packet.
    [Show full text]