Kudithipudi.Org Too much time on hand!!!

June 16, 2014

HOW TO : Parse IP Address in Windows Batch File

Filed under: Programming,Technology,Windows — Vinay @ 11:04 am

We had a recent challenge at work which required us to execute different actions based on which office a particular workstation was located in. Since we have unique network ranges per office, I thought this would be a good variable to use. Just for future reference, here is how we accomplished this in a batch file. The workstations were running Windows 7


FOR /f "tokens=3" %%I IN (
'netsh interface ip show address "Local Area Connection" ^| findstr "IP Address"'
) DO SET ipAddress=%%I

REM "Office 1"
IF NOT x%ipAddress:10.130=%==x%ipAddress% (
ECHO "Office 1" + %ipAddress%
ECHO "do_something_else" )

REM "Office 2"
IF NOT x%ipAddress:10.140=%==x%ipAddress% (
ECHO "Office 2" + %ipAddress%
ECHO "do_something_else" )

Details of function used

  • netsh interface ip show address “Local Area Connection” : With this command we are extracting the IP information of just the LAN port
  • findstr “IP Address” : returns the line containing “IP Address”
  • IF NOT x%ipAddress:10.130=%==x%ipAddress% : We are using the substitution function and returning false if the new string doesnt match the original
  • FOR /f “tokens=3″ : Using the functions in the FOR loop to extract the third variable in the matching line

February 14, 2014

Update 1 : Application Development : domainScan

Filed under: Programming,security,Technology — Vinay @ 3:07 am

Following up from my post earlier this month regarding building a security application that scans publicly available data (Google) and report on potential information leakage from a hostname.

I created a repo on github if anyone is interested in contributing. First thing any good developer does is to check code in early and often :). The repo is at https://github.com/kudithipudi/security-domainscan

Here’s the sudo code I put together as a framework to build on

 open file;
 for each line

 write to log

 search_google (hostname)
 connect to google api
 get results for hostname
 return number of results



February 13, 2014

HOW TO : Search for a record in MongoDB based on length

Filed under: Databases,HOWTO,Technology — Vinay @ 2:40 pm

Quick entry for my own records.

MongoDB is one of the popular open source document database that is part of the nosql movement. One of the applications we deployed at work uses MongoDB as an internal storage engine. We ran into an issue where MongoDB was trying to replicate data to MySQL and the replication stopped because of a size mismatch for an object between MongoDB and MySQL. Essentially MongoDB was trying to insert a record into MySQL that was larger than the defined length.

Here is the query we used to find the culprit objects. We used the awesome Robomongo client to connect to the MongoDB instance.

db.some_table_to_search.find({$where:"this.some_column_to_search.length > 40"})

Breaking down the command

db -> Specifies the database you are trying to search

some_table_to_search -> Specifie the table you are trying to search

some_column_to_search -> Specified the particular column you are trying to search.

In this specific example, we were looking for entries longer than 40 characters for this column.

If you come from the traditional RDBMS world, here is a link from MongoDB comparing terminology between RDBMS and MongoDB.


February 3, 2014

Idea for a security application

Filed under: Programming,Technology — Vinay @ 2:01 am

I think the best way to learn a new (programming) language is to address a real world problem :). So here is one, I want to solve in the next few months.

One of the things I like to do as part of a evaluation security process is to check the amount of public information available for a website. I frequently find that people find information leakage from websites they thought were secure or not publicly accessible.

The idea is to create a python script to do the following

  • Must have
    • Inject list of hostnames and do the following
      • Check whether they resolve to a public IP or not
      • If resolving to public IP, check the amount of data being exposed by this site by doing a quick google search
      • Report on the amount of information available sorted by amount
  • Nice to have
    • take domain name instead of hostnames and try to do a domain transfer and capture all hostnames in the domain
    • leverage Google API instead of web scraping
    • web interface to allow input and show output

Why python? Well, I have been trying to learn it for sometime now and I think it is time to put all that learning to use :).

Anyone interested in joining the fun?

January 28, 2014

Lessons of the trade : Handling CVV numbers

Filed under: Programming,security,Technology — Vinay @ 9:16 am

Just for my notes.. Even though the CVV numbers on a credit card, look like numbers :), don’t treat them as integers in your code. Some of the numbers start with a 0.. so 059 might become 59 by the time you try to process it if you capture the CVV field as an integer.

Just treat them like a string.

And obviously you are not storing them anywhere in your application/network :). Or you might end up in the headlines like some of our retailers.

January 27, 2014

Overheard : Comment about Hardwork

Filed under: OverHeard — Vinay @ 12:11 am

Interesting analogy to Thomas Edison’s quote “Genius is one percent inspiration, ninety-nine percent perspiration” by Elizabeth Gilbert on a recent Radio Lab show

99% Oyster and 1% pearl

January 7, 2014

Overheard : Comment about what is takes to be a competent person

Filed under: OverHeard — Vinay @ 9:46 pm

Came across quote by Robert A. Heinlein on a blog post by Jacques Mattheij regarding a what a competent man should be able to do

A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.

January 6, 2014

Parenthood means..

Filed under: Family,Fun,Rantings — Vinay @ 10:55 pm
  • Not hesitating for a moment to put your nose near someone’ arse to check if they pooped
  • Thinking it is cute when someone pees in your bed
  • Taking food that someone else spits out and finishing it off without hesitating for a second

Some of the joys I got to experience in the last two years raising our Son :).

And yes.. a whole lot of new found respect for my parents.

April 10, 2013

HOW TO : Convert PFX/P12 crypto objects into a java keystore

Filed under: HOWTO,security,Technology — Vinay @ 8:37 am

We needed to add a certificate that is currently in PKCS#12 format currently into a java keystore at work recently. The typical step would be due to create an empty keystore and then import the certificate from the PKCS#12 store using the following command

keytool -importkeystore -srckeystore sourceFile.p12 -srcstoretype PKCS12 -destkeystore destinationFile.jks

Note: PKCS#12 files can have extensions “.p12″ or “.pfx”

The command executed without any issues, but we received the following error when we started the application server using this newly created keystore

java.io.IOException: Error initializing server socket factory SSL context: Cannot recover key 

It didn’t make sense, because we were able to view the certificate in the keystore and were using the right password in the configuration files.

After a lot of searching and head scratching, the team came up with the following solution

  1. Export the public key and private key from the PKCS#12 store using openssl.
  2. Import these keys into the java keystore (default format of JKS)

The commands used were

openssl pkcs12 -in sourcePKCS12File.p12 -nocerts -out privateKey.pem
openssl pkcs12 -in sourcePKCS12File.p12 -nokeys -out publicCert.pem
openssl pkcs12 -export -out intermittentPKCS12File.p12 -inkey privateKey.pem -in publicCert.pem
keytool -importkeystore -srckeystore intermittantPKCS12File.p12 -srcstoretype PKCS12 -destkeystore finalKeyStore.jks

February 26, 2013

HOW TO : Use grep and awk to find count of unique entries

Filed under: HOWTO,Linux,Technology — Vinay @ 11:11 pm

I have use grep extensively before to analyze data in log files before. A good example is this post about using grep and sort to find the unique hits to a website. Here is another way to do it using grep and awk.

Say the log file you are analyzing is in the format below and you need to get the unique number of BundleIDs

2013-02-25 12:00:06,684 ERROR [com.blahblah.sme.command.request.CustomCommand] Unable to execute AssignServiceCommand, request = '<AssignServiceToRequest><MemberId>123456</MemberId><OrderBundle><BundleId>5080</BundleId></OrderBundle></AssignServiceToRequest>'

you can use grep and awk to find the number of times a unique bundleID appears by running

grep -i bundleID LOG_FILE_NAME | awk '{ split ($11,a,">"); print a[6]}' | sort | uniq -c | sort -rn 

breaking down the commands

grep -i : tells grep to only show the lines from the file (LOG_FILE_NAME) containing the text bundleID and makes the search case insensitive

awk ‘{ split ($11,a,”>”); print a[6]}’ : tells awk to grab the input from grep and take the 11th item (by default awk separates content with a space) and split the string into an array (a) using > as a delimiter. And finally print out the value of the array a’s sixth member

sort : sorts the output from awk into ascending order

uniq -c : takes the output from sort and counts uniq items

sort -qn : takes the output from uniq and does a reverse order sort

The output looked like this

173 5080</BundleId
12 5090</BundleId
8 2833</BundleId
1 2412</BundleId
1 2038</BundleId
1 1978</BundleId
1 1924</BundleId
Older Posts »

Powered by WordPress