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HOW TO : Download SSL certificate using openssl and importing it into a keystore
Following up on my earlier post about using keytool to import and export certificates into a keystore. Here is some more information on using openssl to download the certificate from a remote server and then using keytool to import it into the keystore.
keytool needs the certificate to be in X509 format, so we will use sed to format the certificate.
[code]echo -n | openssl s_client -connect HOST:PORTNUMBER | sed -ne ‘/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p’ > /tmp/$SERVERNAME.cert [/code]
breaking down the command
[code]echo -n[/code]
send an end of line signal to openssl. This allows openssl (or rather the server it is trying to connect to) to disconnect the session
[code]openssl s_client -connect HOST:PORTNUMBER[/code]
asks openssl to act as a client and connect to the HOST on the specificed PORTNUMBER
[code]sed -ne ‘/-BEGIN CERTIFICATE-/,/-END CERTIFICATE-/p’ [/code]
asks sed to take the input from openssl and only output the content between BEGIN CERTIFICATE and END CERTIFICATE.
NOTE: If you get an error like “SSL routines:SSL23_GET_SERVER_HELLO:sslv3 alert unexpected message”, it means the server doesn’t support SSL negotation. Using the command option -no_tls1 helps work around this error. This option will tell openssl to disable TLS1 negotiation.
2012 Half Marathons : An update
Quick update on the races Jhanvi and I ran so far this year. And yes, she kicked my butt in all of them as usual 🙂
2012 Rock and Roll Chicago Half Marathon
Showing off our medals in the train back home.. It was painful 🙂 
Endomondo’s view of how I ran 
2012 Northface Challenge : Madison
This is the third time, I am running this trail half marathon. And for the first time, I actually did better than the last race. And it was mainly due to Jhanvi encouraging me to practice. Not my best time, but better than last year 🙂
HOW TO : Compare two directories in Linux
Quick post on using diff to compare two directories in Linux. This will show the list of files and subdirectories that are different in either directories
[code]diff /PATH_TO_FIRST_DIRECTORY /PATH_TO_SECOND_DIRECTORY -r –brief [/code]
Options used
- r : Searched recursively through the directory
- –brief : Only shows the names of the files that differ. If you want details of the content that differs, remove this option
HOW TO : grep for response codes in apache logs
If you want to grep for certain http response codes in a apache log file
- Look for all access requests with a 200 response code[code] grep -i "[: ]200[: ]" HTTP_ACCESS_LOG [/code]
- Look for all access requests that do NOT have a 200 response code[code] grep -i -v "[: ]200[: ]" HTTP_ACCESS_LOG [/code]
Details of the options
- [code]"[: ]"[/code]
tells grep to look for space or tab before the specified string, which in this case is 200.
Another day.. Another Hack
The net is up in arms about a new release from team Ghostshell of compromise data. Details of the leak can be found at http://www.theregister.co.uk/2012/08/28/team_ghostshell_megahack/ and the source of the data is at http://pastebin.com/BuabHTvr .
I thought I would put my nascent python skills to use and write a simple script to parse through the release and download all the data. Hoping to analyze it later on. It is pretty basic, but does the job of parsing the release and downloading the content. You can get the script at https://github.com/kudithipudi/Misc-Scripts/blob/master/parseHellfire.py
Watch out for an analysis of the content soon :).
HOW TO : Use openssl client to check for PCI compliant SSL ciphers
Simple one liner to check if your web server is using strong ciphers
[code]
openssl s_client -cipher LOW -host SERVER_NAME -port 443 [/code]
HOW TO : Use Python to look for credit card numbers
Simple script in python to look for credit card numbers in a file.
[code]
#Importing modules
import re
import os
# Define variables
inputFile = ‘test.txt’
searchPattern = ‘((\D(6011|5[1-5]\d{2}|4\d{3}|3\d{3})\d{11,12}\D)|(^(6011|5[1-5]\d{2}|4\d{3}|3\d{3})\d{11,12}\D))’
tempinputFile = open(inputFile)
tempLine = tempinputFile.readline()
while tempLine:
print ("LINE: " + tempLine)
foundContent = re.search(searchPattern,tempLine, re.IGNORECASE)
if foundContent:
print("FOUND: " + foundContent.group())
tempLine = tempinputFile.readline()
tempinputFile.close() [/code]
The script started out as a simple check for any 16 digit numbers that had a non numeric character on either end. But I tweaked it a little bit to look for credit card like numbers using the regex from http://www.regular-expressions.info/creditcard.html. Finally I added an option to match credit card like numbers if the numbers start at the beginning of the line (i.e there is no non-numeric number before the credit card number)
OVERHEARD : Comment about fudging
Actually, this is more of a read on the web post. New acronym for describing technology that doesn’t really help
CBT : Cock-n-Bull Technology
🙂
HOW TO : Find files, search for content in them, replace the content
The title pretty much says it all :). Here is a quick one liner, using multiple tools, to look for files in a directory, search for certain content in them and replace them with other content
[code]find -type f | xargs grep -l ORIGINAL_CONTENT | xargs perl -p -i -e ‘s/ORIGINAL_CONTENT/NEW_CONTENT/g’ [/code]
You can theoretically take out the grep (second command) and directly pipe the find output to perl and get the same outcome.
Going over list of the options used
find
- “-type f” lists all objects of type file in the directory (and sub directories)
grep
- “-l” lists the names of the files (with relative path) which have the text ORIGINAL_CONTENT in them
perl
- “-p” forces perl to loop through requests. In this case files
- “-e” tells perl that the next argument is a perl statement
- “-i” tells perls to edit the file in place (i.e. no need for an output file)