How Chaining Of Attack Vectors Gave Defencely an Upper Hand in Pentests!?


Today as part of our ongoing efforts to spread cyber security awareness, we’ve taken measures to go an extra mile & bring you rich blog posts about tales & adventures at Defencely Lab. We are going to explain & demonstrate how we chained up critical information to gain access to millions of customer accounts in order to safeguard our valued clientele pro-actively.

We are intentionally excluding the names of the target to stick to confidentiality clause which we’ve signed up. At this point, our readers should be able to have an analogy of the steps which are taken & mentioned in this post to get the complete picture of what’s happening.


  1. Understanding the workflow of the Application.
  2. Technical Understanding.
  3. Chaining up and Exploiting the vulnerability on the basis of Collected information.


Our target had an Android Application as well as a Web Application giving ourselves a wide scope to start enumerating and having a general idea of how their applications were working at the back-end, we look our own research time to be spend wisely before we actually started to hit the targets.

Working of the Web Application: This web application allows anyone to Sign Up for their services hosted on a particular sub-domain say And once you’re signed up as a normal user with the company you can upload your details and information related to you on the account to set it up according to the services offered.

Working of the Android Application: This Android Application is of their Partners Portal. The Android Application was more interesting as this Application doesn’t allows everyone to sign up as a Partner, You need to verify yourself as a legitimate person having skills on the works they offer & submitting documents related to the work they are offering. We reverse engineered the APK file & The only thing which were similar between the Web App & the Android App was both their APIs which were connecting to the same domain but having different endpoints.

So, this was going really interesting as we do not have access to any of their test credentials for the Partner’s Android App to test their API endpoints. We were only left with the reverse engineered files & codes on the desk. Now we have a basic idea about how things were working, let us jump into the technical understanding of the application and lets understand how we escalated this from having nothing to compromising millions of their accounts registered with the company.


If you want to register yourself as a Partner you need to call them on a given number on the website to their 24 * 7 available customer support and can provide details they needed to verify yourself as a legitimate partner.

So, what would you have done if you were at the same scenario we were? It’s obvious. We called them up & social engineered them to make them believe that we want to sign up as a partner and provided some legit looking details which were actually dummy details created at our end. The verification process was over, everything went fine. But they informed us that they will take couple of days to provide us the credentials to partner portal. We know we have deadlines, 2-3 days was a long time and we can’t afford wasting time on just registering a account on their partner’s portal.

If you remember we already have reversed engineered the APK file. So we went that way. We started looking into the huge source codes available.

We were looking through the directory structures and found some susceptible files where we can now at least concentrate into.

Above are the files we were specifically looking into. We started reading the codes of the  file. And within a couple of minutes we found something really interesting which took our attention and made everything clear about the Login mechanisms they were using and how they were Saving passwords to the databases at the back-end.

Lets look at the code and understand the mechanism.

Vulnerable Code which could allow us to take over Partner Accounts: 

void getSavePassword(@Field("mobile") String str, @Field("password") String str2, @Field("confirmPassword") String str3, Callback<OTPModel> callback);

This particular function took our attention which were sending some form-collected data into the POST parameters to the endpoint /ppapp/savepassword. I was pretty sure the developers were using this function to set new passwords for the users.

But here the question arises. How we are going to exploit this vulnerability? If we look into the function, we can see the function getSavePassword takes three functions parameters in.

getSavePassword(@Field("mobile") String str, @Field("password") String str2, @Field("confirmPassword")

  1. `mobile` parameter
  2. `password` parameter
  3. `confirmPassword` parameter

We need to full fill the need of supplying three parameters to the function to make the request happen. You might have noticed they are changing the password of users putting mobile phone number as their uniquely identified kind a`key`.

The first priority here is we need to have a mobile number already registered with the company. And to full fill the need we started enumerating other files which might throw us some more details regarding users already registered.

While enumerating other files, we found another endpoint which seems to be related with the customer profile details or vice versa.

We started searching where and how this endpoint @GET("/getprofilejson") is working by looking at the source codes left with us.

We found that the endpoint @GET("/getprofilejson") is working with two HTTP GET parameters.

  1. `uri`
  2. `consumerId`

Enumerating the source codes more and more gave us the values which were fitting into these two parameters. The `uri` parameter is taking a `location` which in my case was %2Feast%2Fassam%2Fbongaigaon%2F and `consumerId` was of 6 digit integer value, so i just passed a random 6 digit integer value ‘123456’ But nothing happened.

I wrote a python script to bruteforce the `consumerId`.

The API endpoint was throwing data’s at ‘391149’ which holds a token value for ‘example_profile_id’ and meant to be supplied as HTTP POST  parameter on the endpoint @GET("/getprofilejson") as "example_profile_id=82f088332d0611e484950e2f866a9102" to get hold on the registered customer profile details.

Our goals are achieved. Now we have a registered customer’s phone number. It’s time to code a exploit and make it happen. Lets jump into the last section of exploitation.



A coded up exploit to account take over.


We finally coded a mass account take over exploit where the script grabs user’s phone number bruteforcing the `consumerId` and passing the token value retrieved from the response to get phone numbers of the users and finally the invoking the  @POST("/ppapp/savepassword") endpoint to directly changing the password.


That’s all we have for now. Let’s look forward to more amazement at Defencely Red Team Operations Labs next week for absolutely yet another amazing uncover story of how we’re adding value to our customerbase with insider threat program as well as routine sound-ful & an offensive Vulnerability Assessment followed by a Penetration Test for critical applications both at the staging level & production bases. Our manual security assessments methods have proved the best value. Feel free to touchbase at, Shritam Bhowmick, Red Team Lead @Defencely for any Security Operations Related queries or say “Hi” to us at for inquiries.

We should see you again next week with another operational tale of the broad security premises where 0days are always a possibility & at proximity of a security compliance issue which always will be a sooner or later decision by the Indian E-Commerce Management & stakeholders.

Let’s act pro-actively.

Solution to Cutting Out Cost Expenditure on Information Security

It’s not at all by surprise that information security is most expensive task and is closely knit to risk managers to provide quality assured security to it’s end-product be it: web applications, thick clients or in general software. To reduce overthinking over complicated executive level decision by project managers, it’s essential in general to know how an information security program works.

How to access necessary components for Enterprise security solutions?

The first approach to solving a problem is to understand it’s question. In information security, the question for an organization is to solve security gaps by placing a security program a provide a security plan further to eliminate this rising security gap but how shall the security program look like and how it shall commence is entirely upto security managers. The necessary components are to be placed before the administration and gain an approval to commence these components in order to manage enterprise risks – which includes ‘security’.

In applications, this entire Application life-cycle management (ALM) will have a particular process and it’s components will be essentially:

  1. people
  2. process
  3. product


Security management for all of them have to be taken into consideration, whether it’s to educate it’s people about security and provide required awareness about information security policies around the organization, secure processes for the organization and the secure product itself. This can be a top-down approach to provide a framework for security (security program) and then plan security in specific ways to protect business assets and it’s interests of the organization. During this entire time in the process, cost can be a factor due to the approved budget for the program and maintenance of the security program to keep solving security gaps in a way they should be.

How to solve ”cost” factor in a security program?

The security managers takes decisions related to security and hence should be able to decide the overall cost in recurring terms. But it’s not just about determining the cost – it’s also about cost cutting to9 get the project budget fixed without affecting the quality provided by the security program. First it’s necessary to access what accomplishments are to be made during the entire life-span of an application or the application that is being developed in-house and will be in production servers after it’s deployed. Some of these have to be considered while setting by layout and determine the costs:

  1. Objectives
  2. Required people
  3. Required outsourcing
  4. Required maintenance

The objectives should be very clear to the project managers in order to set the right people in-house to handle security problems and these people will be responsible to handle and mitigate risks and plan further with internal development teams. It’s also necessary to outsource tasks which needs subject matter expertise since security isn’t about just one thing. When discussing information security – for an instance there might be one than more components that are to be taken care of such as:

  1. secure coding practices in-house
  2. architectural risk analysis
  3. threat analysis
  4. security audits
  5. penetration testing

For most applications, the first three is done in-house and these includes costs too. Involvement of penetration testing comes from outsourcing after the product or software (web applications) are deployed but during SDLC a ‘secure’ mechanism has to be placed which gives birth to SSDLC (secure SDLC). Most threat analysis come after risk analysis has been done at an architectural level because managers have to decide on resource that is to be allocated to each of these components. To cut costs, it’s required that skilled-labor are employed to each of the steps in security framework rather than trying to randomly handle security which most often fails and which isn’t cost effective at-all. Threat analysis will involve:

  • threat modeling
  • threat treatment
  • threat management

Thereat management people and it’s resources will also be responsible for the later results which are out during penetration tests and in-case expected outputs are not acquired, a team of expertise should be able to look at the functional dependency and improve their formal test cases which are two:

  1. positive testing (functional testing)
  2. negative testing (exceptional testing)

Functional testing means what web applications are supposed to do i.e. input v/s output and negative testing means how the applications handle exception or are there any ways in which exceptions occur, and could these lead to business risks? Most of the negative test cases are something which needs focus since they are the elements to which later penetration testing proves unit security testing wasn’t effective and that can be something which might be of concern. Why? because at later stages costs comes to an exponentially to manages security risks and accordingly rearrange and re-implement to make a correction and make the product work without it’s security being affected (and also since organizations have to maintain compliance).

These pointers are small things where the cost cutting can be most accurate because if a pin-point analysis is done how such extra costs can be reduced in security programs, so that at later stages all of it contributes to an overall security budget of the organization. Sometimes it’s also the reason why organization now outsource finance to managed bug bounties. To deliberately handle security the right way, it’s also necessary to keep quality while in the SDLC period, since after the product is released – it might be out of hand and a little too late for managers to manage security.

How does Defencely solve your problems?

Defencely provides a 360 security solution to organizational security problems whether the products are in SDLC or it has been already deployed. If applications are in SDLC phases, it’s more beneficial to cost-cut your resources and get dedicated security expertise to help you realize and reduce risks before any commitments or deployments to your applications – it’s like winning the war before it starts. This could also be beneficial to compliance that the organization has chosen and the required reports it needs to prove their applications are secure for it’s customers and end-users.

The solutions provided is overall and hence it’s extremely helpful to know if certain application passed improvement to maintain a continual security check . This can be in terms of application security assessments, penetration tests, and simulated security testing where a red team accesses your applications in offensive ways to determine measure of security and give your organization the overall security posture. Let’s get you started with the right security program for your platform, contact us to get to help you solve your enterprise security problems.

About the Author

Shritam Bhowmick is an application penetration tester professionally equipped with traditional as well as professional application penetration test experience adding value to Defencely Inc. Red Team and currently holds Technical Expertise at application threat reporting and coordination for Defencely Inc.’s global clients. At his belt of accomplishments, he has experience in identifying critical application vulnerabilities and add value to Defencely Inc. with his research work. The R&D sector towards application security is growing green at Defencely and is taken care by him air max sale. Professionally, he have had experiences with several other companies working on critical application security vulnerability assessments and penetration test security engagements, leading the Red Team and also holds experience training curious students at his leisure time. He also does independent application security consultancy.

Out of professional expertise at Application Security, Shritam Bhowmick utilizes his knowledge for constructive Red Teaming Penetration Testing Engagements for Indian Top Notch Clients and has a proven record for his excellence in the field of IT Security. A Google search with his name would suffice the eye. Shritam Bhowmick has been delivering numerous research papers which are mostly application security centric and loves to go beyond in the details. This approach has taken him into innovating stuff rather than re-inventing the wheel for others to harness old security concepts. In his spare time, which is barely a little; he blogs, brain-storms on web security concepts and prefers to stay away from the normal living. Apart from his professional living, he finds bliss in reading books, playing chess, philanthropy, and basket-ball for the sweat. He wildly loves watching horror movies for the thrill and exploring new places for seeking new people alike.