Skip to main content

TcpDumpTutorial

When using a tool that displays network traffic a more natural (raw) way the burden of analysis is placed directly on the human rather than the application. This approach cultivates continued and elevated understanding of the TCP/IP suite, and for this reason I strongly advocate using tcpdump instead of other tools whenever possible.

An anagram for the TCP flags: Unskilled Attackers Pester RealSecurity Folk ]
Show me all URGENT (URG) packets...
# tcpdump 'tcp[13] & 32!=0'

Show me all ACKNOWLEDGE (ACK) packets...
# tcpdump 'tcp[13] & 16!=0'

Show me all PUSH (PSH) packets...
# tcpdump 'tcp[13] & 8!=0'

Show me all RESET (RST) packets...
# tcpdump 'tcp[13] & 4!=0'

Show me all SYNCHRONIZE (SYN) packets...
# tcpdump 'tcp[13] & 2!=0'

Show me all FINISH (FIN) packets...
# tcpdump 'tcp[13] & 1!=0'

Show me all SYNCHRONIZE/ACKNOWLEDGE (SYNACK) packets...
# tcpdump 'tcp[13]=18'
[ Note: Only the PSH, RST, SYN, and FIN flags are displayed intcpdump's flag field output. URGs and ACKs are displayed, but they are shown elsewhere in the output rather than in the flags field ]
Keep in mind the reasons these filters work. The filters above find these various packets because tcp[13] looks at offset 13 in the TCP header, the number represents the location within the byte, and the !=0 means that the flag in question is set to 1, i.e. it's on.
As with most powerful tools, however, there are multiple ways to do things. The example below shows another way to capture packets with specific TCP flags set.
Capture TCP Flags Using the tcpflags Option...
# tcpdump 'tcp[tcpflags] & & tcp-syn != 0'

Comments

Popular posts from this blog

Install Virtual Box On Kali Rolling

If you facing problem with virtualbox installation on kali rolling edition because of its outdated kernel 4.3.0-kali1-amd64 then this post is for you only.

Step1: Install latest kernel. First search the cache for list of available ones apt-cache search linux-headers
Depending upon the list choose one from the set and install install it.
you can download kernel file using wget from ubuntu source also.
example:wget kernel.ubuntu.com/~kernel-ppa/mainline/v4.4.3-wily/linux-image-4.4.3-040403-generic_4.4.3-040403.201602251634_amd64.deb
for more refer to this post: link

Step2:
Edit the boot entry /boot/vmlinuz-(New Linux kernel Version) & /boot/initrd.img-(New Linux kernel version) in grub menu.

Before making boot entry changes be sure these files exist in the /boot directory after running install command.
In my case following new file got created in /boot folder:

1)vmlinuz-4.6.0-kali1-amd64
2)initrd.img-4.6.0-kali1-amd64

Thats all you need to do to install any virtual software on kali r…

Hacking Windows 10 UWP App: DLL Injection & common Vulnerabilities

I recently started working on  widows 10 Apps( Apps not Applications) security. Before diving deep in hacking terms lets try to understand what's new in Windows 10 UWP( Universal Platform) as compared to old Apps. Lets begin with how apps actually work on windows 10(desktop/tablet). Now windows 10 comes with a container only for running apps inside the isolated environment. By default, /APPCONTAINER(Linker Flag) is off. This option modifies an executable to indicate whether the app must be run in the appcontainer process-isolation environment. Specify /APPCONTAINER for an app that must run in the appcontainer environment—for example, a Windows Store app. (The option is set automatically in Visual Studio when you create a Windows Store app from a template.) For a desktop app, specify /APPCONTAINER:NO or just omit the option. The /APPCONTAINER option was introduced in Windows 8.
Now there is no registry entry concept for these app in the System HIVE rather they install they own hiv…

Assignment 01(Enroll TO Offensive-Security Course)

Steps 1:download the page.
2:open fc4.js in your favourite editor and add following lines in it or just replace it with vode given below.
3:then open the download html file in browser and fill the form with your email and a garbage value string.
4:thats it? it will show you the real security string??
yeah but  ...theirs another challenge waiting for you ... :D

function fc4me(srvstr) {

   if(!document.pleazfc4me.email.value || !document.pleazfc4me.securitystring.value) {
      alert("Please fill in all the required fields!");
      return false;
   }
   else {
      document.pleazfc4me.submit();
    }
   var t=hexMD5("\x74\x72\x79\x68\x61\x72\x64\x65\x72"+srvstr)
alert(t)
document.write(t)
}



Finally Got In :-)