Zespre's Blog

GitHub has already provided a nice platform to host your static blog which called GitHub Pages, but I still want to build my system which could achieve the same goal.

Generate Certificate and Key pair To import the certificate with its private key, you can do the following: Pack the certificate and its private key into a PKCS #12 file or PFX file using openssl pkcs12.

Nowadays, people who develops FreeBSD Ports are using automated tools, e.g.

I moved into dorm this semester again.

I don’t know where and when I set this, but XenCenter keeps telling me that I cannot add more virtual disks (currently only 3 virtual disks) to my virtual machine.

Security Programming Homework 2-2 Alphanumeric Shellcode Executor Once connect to the service, it will prompt the following message: $ nc secprog.cs.nctu.edu.tw 10022 Welcome to AlphaNumeric Shellcode executor!

Problematic Calculator First of all, the file name is “calc.exe”.

I want to build a Micro Computer Center (MCC) Requirement & Architecture There will be 3 machines in the MCC environment. sahome (NIS master server, NFS server) saduty (NIS slave server, NFS client) sabsd (NIS client, NFS client) The architecture is shown…

Security Programming Homework 4-1 Problem Description The ShellShock Tester is the website that have some vulnerabilites.

2014/12/16 Secure Programming Class Note 今天的課程請到 Orange Tsai 大大，講題為 Web Security。

2014/12/09 Secure Programming Class Note SQLi1 need encode ’ ' http://tor.atdog.tw:8080/union/news.php?

System Administration Kernel and Driver Note Kernel-wide Design Approaches Monolithic Kernel Entire operating system is working in kernel space Efficient But hard to maintain Can dynamically load executable modules at runtime Linux, *BSD, MS-DOS, Windows…

Sometimes we want to debug a program which acts interactively with user.

Security Programming Homework 3-2 Finding Weak Points After using gdb to do the dynamic analysis, I found that function main() will call function get_request().

One day I received an root mail from my machine, talking about some packages are broken in the cache.

Mininet Mininet is a network simulator, running real kernel, switch, and application code.

2014/11/18 Secure Programming Class Note Flash 0 Day DEP ASLR EMET browser sandbox rop fop Attack & Defense token pcap per round, delay about 3 rounds (3 rounds ago) exploit binary patch wrapper traffic analysis monitoring ld preloading xinetd

20141119 Wireless Internet Laboratory meeting Introduction The demand for bandwidth between servers inside a data center is rapidly increasing High bisection bandwidth and high availability Efficient use of multiple paths between pair of end hosts The con…

Security Programming Homework 2-1 Intelligence Gathering There is a vulnerability in piece of code which contains strtok() There is a call eax in the binary Because it is an interactive shell program, bad characters are 0x00, 0x0a, 0x2f (filter out by spe…

2014/11/06 Network Programming Class Note Semaphore Big semaphore, small semaphores Shared Memory

2014/11/04 Secure Programming Class Note foo_4 Training for “return to text” attack. binsh: 0x0804a030, but actual address is at 0x08048640. system: 0x080483e0 print 'a'*24 + '\xe0\x83\x04\x08' + 'aaaa' + '\x40\x86\x04\x08' foo_5 Training for “return to l…

20141029 Wireless Internet Laboratory meeting Abstraction Two representative monitoring tasks Flow size counting Packet sampling Distributed and Collaborative Monitoring system (DCM) Allows switches to collaboratively achieve Flow monitoring tasks Balance…

2014/10/28 Secure Programming Class Note \xdc\xed\xbf\xbf\xdd\xed\xbf\xbf\xde\xed\xbf\xbf\xdf\xed\xbf\xbf%100 c%30$hhn%220c%31$hhn%55c%32$hhn%66c%33$hhn get_flag(): 0x0804861d 29 %29c 134 %105c 4 %97c 8 %97c %29c$hhn%105$hhnc%97c$hhn%97c$hhn

Sometimes we don’t want to do the installation in front of the console Before Started Writable Filesystem mkdir /tmp/etc mount_unionfs /tmp/etc /etc Connectivity ifconfig em0 140.113.102.184 netmask 255.255.255.224 route add default 140.113.102.190 echo…

2014/10/21 Secure Programming Class Note GNU Debugger Skill (gdb) disassemble foo (gdb) b *foo+40 (gdb) r (gdb) display/i $pc (gdb) x/10xw $ebp+0x10 (gdb) x/20xw $esp-0x20 (gdb) ni (gdb) i b Buffer OverFlow Disable stack guard gcc -fno-stack-protector D…

First time of my life I solved a problem in a real CTF!

2014/10/16 Network Programming Class Note Byte Order Little endian: int -> short is convenient (still implemented in most PCs) Big endian: straight forward, hence become main trend (media formats, networking) | | Big endian A ------> | | 0 1 A A+1 A+2 A+3

It is hard to find a command-line-based ftp client that support SSL/TLS.

2014/10/09 Network Programming Class Note Return value of read() equals 0 means that it is the end (blocking mode) pipe: the write end has been closed file: end of file create pipe 時 read 的 FD 先於 write 的 FD, e.g. read = 3 and write = 4 cat f1 | sort | lpr…

System Administration GUID Partition Table Note Introduction MBR and GPT are partition schemes GPT is a standard for the layout of the partition table on a physical hard disk, using globally unique identifiers (GUID).

Security Programming Homework 1-1 Get Flags According to the first hint: “Try to capture as more flags as you can.”, I think we should use to Tor to visit the website.

Security Programming Homework 1-3 Using IDA Pro’s impressive F5 decompilation, we discover sub_80485D7() is the most interesting part ...... v6 = ptrace(0, 0, 1, 0); ...... if ( a1 !

2014/10/02 Network Programming Class Note exec() exec() does not create new PID, only fork() spawn new PID loader does not change FD table ex: execl("ls", "ls", "-la", "d1") exit() exit() has an argument that means error code, to parent flush the buffer b…

2014/10/01 Computer Networks Class Note An IP subnet is a consecutive address block Strong implication of location ydlin’s opinioon: Mobile IP is not a good idea Destroy the nature of IP subnet Subnets are nearby may be good for Mobile IP

2014/09/30 Secure Programming Class Note Skills ltrace: trace library function call strace: trace system call gdb break <func_name>/<mem_addr>: set break point run <cmd_args>: just like you type commands in terminal normally x/s: show strings x/i <mem_add…

Open the management ports carefully I found that there are great amount of records about SSH bruteforce from the Internet in logs.

XenServer does not have a local ISO repository by default.

Vsftpd is one of the packages in Arch Linux offical repository.

Build my own environment for network experiment!

2014/09/25 Network Programming Class Note Memory User Context +----------------+ | stack +----------------+ | +----------------+ | heap +----------------+ | uninitialized data +----------------+ | initialized | read-write | data +----------------+ | +----…

2014/09/24 Computer Networks Class Note circuit hard-state soft-state stateless switching switching switching routing stateful|---------------+--------------+---------------|stateless POTS | ATM MPLS Internet | (packet C/S | P/S switching) ISPs cha…

2014/09/23 Secure Programming Class Note Static Analysis Skill On Linux you can do the following: file <executable> strings <executable> objdump -d <executable> Also, there is a powerful tool on Windows called “IDA Pro”.

2014/09/22 Computer Networks Class Note Circuit Switching FallBack (CSFB) LTE networks fallback to 3G Network circuit switching while calling and sending/receiving SMS because of two reasons: Technical issue Business concern Path Routed Stateless (connect…

I need a handful tool to manage my Python versions and also packages.