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Security in CPS/Networking

• ARP Cache

  Security in CPS/Networking 2019. 10. 18. 09:40

  다음 명령어를 통해 로컬에 저장되어 있는 ARP 캐쉬 정보를 확인할 수 있습니다. $> arp -n 1 2 3 4 5 $> arp -n Address HWtype HWaddress Flags Mask Iface 10.0.1.138 ether 00:00:00:00:00:01 C r1-eth0 10.0.2.10 ether 00:00:00:00:00:02 C r1-eth1 http://colorscripter.com/info#e" target="_blank" style="color:#4f4f4ftext-decoration:none">Colored by Color Scripter

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• [Problem] No SYN,ACK in TCP 3-ways handshake

  Security in CPS/Networking 2019. 10. 15. 08:53

  [Problem] A Client can not receive SYN,ACK packet from A Remote Server even though it can successfully do PINGs between them. Environment: Customized Mininet Topology [Check Point] 1. Capture TCP packets on a virtual ethernet. 2. The port is open or not 3. Firewall in a host is working or not

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• [아파치] 커스텀 모듈 빌드 및 로딩

  Security in CPS/Networking 2019. 9. 4. 11:05

  https://httpd.apache.org/docs/2.4/programs/apxs.html Welcome! - The Apache HTTP Server Project The Number One HTTP Server On The Internet The Apache HTTP Server Project is an effort to develop and maintain an open-source HTTP server for modern operating systems including UNIX and Windows. The goal of this project is to provide a secure, efficient an httpd.apache.org 1. 더미 모듈을 생성한다. $> apxs -g -n..

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• [apache2] build apache2 (httpd)

  Security in CPS/Networking 2019. 9. 4. 10:55

  http://httpd.apache.org/docs/current/install.html Welcome! - The Apache HTTP Server Project The Number One HTTP Server On The Internet The Apache HTTP Server Project is an effort to develop and maintain an open-source HTTP server for modern operating systems including UNIX and Windows. The goal of this project is to provide a secure, efficient an httpd.apache.org 1. Download source code from the..

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• Install apache2 & check MPM on ubuntu

  Security in CPS/Networking 2019. 8. 28. 09:29

  1. Install apache server $> sudo apt-get install apache2 2. Run apache server $> sudo service apache2 start/restart/stop 3. Check apache server $> systemctl status apache2 4. Check wheither Multi-Processing Module is loading. 1 2 @ubuntu:/etc/apache2$ apache2 -V | grep MPM Server MPM: event 5. Check apache status 1 2 3 4 5 6 7 8 9 10 11 12 13 14 @ubuntu:/etc/apache2$ apache2 -S AH00558: apache2:..

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• UDP DDos threats and vulnerabilities

  Security in CPS/Networking 2019. 5. 21. 16:49

  UDP flood : 많은 양의 snooped UDP 패킷을 특정 포트에게 전달합니다. 이때 서버는 해당 포트가 열려있지 않을 경우 해당 요청에 대한 ICMP 'Destination Unreachable' 메세지를 전달해야 하기 때문에 많은 양의 서버 리소스를 낭비하게 됩니다. DNS amplification : DNS 서버를 공격하는 reflection attack의 한 종류로 DNS 서버로 많은 queries를 전달함으로써 서버 리소스를 낭비하게 하는 공격입니다. UDP port scan : 공격자가 현재 열려있는 UDP 포트를 확인하기 위해 UDP 패킷을 불특정 포트에 전달합니다. 이때 유효하지 않는 포트일 경우 서버는 ICMP ‘Destination Unreachable’ 메세지를 공격자에게 전달..

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• TCP FSM(Finite State Machine)

  Security in CPS/Networking 2019. 5. 21. 10:13

  안녕하세요. 이번에는 TCP FSM 에 대해 알아보겠습니다.. 아래 링트에 내용을 정리한 내용이니 참고하시면 되겠습니다. http://tcpipguide.com/free/t_TCPOperationalOverviewandtheTCPFiniteStateMachineF-2.htm The TCP/IP Guide - TCP Operational Overview and the TCP Finite State Machine (FSM) Please Whitelist This Site? I know everyone hates ads. But please understand that I am providing premium content for free that takes hundreds of hours of time to..

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