Wednesday, July 9, 2014

Risk of self signed certficates

Risks of Using Self Signed Certificate for Authenticity:

Anyone can create a self-signed certificate, and anyone can put whatever meta-data that they want into it. So, two self-signed certificates can look and behave identically, one can't visually distinguish between a legitimate and a forged certificate. It means, anyone can create similar cab file & digitally sign using self-signed legitimate or forged certificates, send to our customers. The customer will not able to differentiate between fake and genuine one.

Risks of Using Self Signed Certificate for Integrity:

User creates a file for distribution using his own self signed certificate and sends to receiver. Here an attacker too creates a his own self-signed certificate with the same name. Attacker does a MITM, captures User’s data, modifies it, removes the signature (in case of dlls, exes just remove from PE header), re-signs with his own self-signed certificate and forwards it to the receiver. This way the data can be tampered and there’s no way for the receiver to detect it as he will be able to decrypt and match the hashes using Attacker’s sent public key.


Wednesday, June 4, 2014

A New Kind of Security: Bionic Labs Wants to Call Your Friends to Verify You’re You

Stumbled upon a good post about a new kind of authentication mechanism, presented by Bionic Labs in Recode conference:

See yourself:

Thursday, May 8, 2014

Wednesday, April 9, 2014

HeartBleed vulnerability

Was about to write about this, meanwhile found this post very useful. Why to reinvent the wheel?
So here you go:
Written by Rahul Sasi.

Tuesday, March 11, 2014

Password reset feature in single user, isolated environment applications

I came across one application while doing security assessment and found that they were using default admin account.And that too the admin account was having credentials as admin:admin. Catastrophic, isn't it?
I raised this issue before completing the assessment with the developers. They had their usual excuse- this was introduced to help user reset their passwords through the web application and since the web application was supposed to be used by singles user. It was essentially a single user environment. The web application was running locally on their individual laptops and the laptop was being plugged on the LAN just for few moments to reset some device readings.

Now the risk was:
Even a momentarily the laptop was connected to local network, the default admin account's presence was known to every other user. If they change the password using the default account then?
Though this was single user environment and only very few users were supposed to use the application on their individual laptops, we can't ignore the risk.

But then there's was no mechanism to reset the password as there was no email accounts associated or nor admin present to reset the password. It was very simple web application to just record and generate reports about some sensors' health.

So after brainstorming, we proposed the following solution in this kind of single user and isolated environment without compromising with usability:
Implementing a feature of local password reset in this single user environment. Develop a CLI (Command Line Interface)/ console based utility which changes the password locally on the machine, rather than providing this facility as web interface as this might be accessed remotely. The utility directly resets the password into database from command line. This approach provides both security and usability in current single user

Monday, February 3, 2014

Testing strategy for Controllers

Controllers are an essential part of ICS (Industrial Control Systems) network. Generally they are interface to many field devices such as sensors and placed within closed network. Exposing them outside world may be disastrous and they can be configured/ mis- configured to carry put attacks which can have dangerous impact on human being's life and safety.

So, it's necessary to do a security assessment of ICS networks to uncover potential vulnerabilties.
In brief, to test a controller we need to:
  • Understand the entire architecture- the platform, technologies, protocol it understands. Do a quick threat modeling here.
  • Review Network architecture, see how the controller is placed, ideally it should not be reachable from internet.
  • Firmware testing: Most of the controllers have embedded systems on them. Do a firmware testing here-
  • De compiling, modifying, patching, looking for hard coded sensitive credentials. How the firmware is uploaded/ downloaded- how secure is the mechanism.
  • Do host level review- Check if the controller is running any unnecessary/ insecure services, open ports, older software versions etc.
  • If web interface is enabled, do a testing from web app level security assessment.
  • If controller is using any proprietary or open source protocol, read the manual and try to understand the stack, what all security issues were discovered historically, what all tools are available in market to test them.
  • Get in touch with developers who work day in out with the technology.

Monday, January 6, 2014

Some general guidelines for a secure firmware

Encryption: It prevents reverse engineering of the firmware. The firmware might be stored in
encrypted form and only decrypted when it is to be executed, or it might be decrypted during the
firmware update process.
• Signing: is concerned with ensuring that a message has not been corrupted or modified while in
transit. This is important since a malicious user cannot be allowed to alter the firmware originally
delivered by the firmware producer.
• No hardcoded credentials: The presence of hard-coded accounts that can serve as backdoors to
• Code obfuscation: it makes runtime analysis difficult.
• Authentication: Make it difficult for unauthorized users to obtain the firmware updates. Make it
restrictive, less exposed.
• If the device is capable of being networked, no unnecessary services are running and ensure that it can also alert and log when firmware has been updated.