TLS version 1.3 is Here : A brief Overview

On 23rd March 2018, the latest version of TLS ,which is TLS 1.3 has been approved by the IETF. There are a considerable number of improvements and differences in TLS version 1.3 over 1.2. Now the developers need to implement this version in to their products and the actual roll out can be expected soon.

Right now, I'm having a Mozilla Firefox version 59.0.1 and by default the TLS1.3 is not yet enabled.

But as per some tech forums, the browser does support TLSv1.3 though its not enabled by default. There are some tips available over internet on enabling TLSv1.3 manually but i'm not going to discuss that here.

On TLS version 1.3,one of the major improvement is the speed.

Those who need a revision on SSL handshake process, can refer to my older post.

So the handshake process in TLS1.2 have more packet exchanges.

The whole handshake process in TLS 1.3 will be now concluded in just 3 exchanges.

But basically the concept is same. Client starts with HELLO, Server responds with its HELLO. then session key exchange.The same process will remain the same for TLSv1.3 version as well but the number of round trip exchanges will be reduced to 3 by eliminating the negotiation on the kind of encryption to use. Instead, the initial connection is a statement from the client mentions what methods and modes i am going to use and server accepts it and respond, that speed up the handshake process. This also helps to eliminate the downgrade attack vector.

A few other major differences between TLS 1.2 and TLS 1.3 are mentioned below.

1)The list of supported symmetric algorithms has been pruned of all algorithms that are considered legacy. Those that remain all use Authenticated Encryption with Associated Data (AEAD) algorithms.The ciphersuite concept has been changed to separate the authentication and key exchange mechanisms from the record protection algorithm (including secret key length) and a hash to be used with the key derivation function and HMAC.
AEAD is the only encryption approach without any known weaknesses.AEAD suites provide strong authentication, key exchange, forward secrecy, and encryption of at least 128 bits. TLS 1.3 supports only AEAD suites. SSL labs started applying scoring penalty consideration for websites that does not having AEAD support.

2) A 0-RTT mode was added, saving a round-trip at connection setup for some application data, at the cost of certain security properties.

It means that if the client has connected to the server before, TLS 1.3 permits a zero-round trip handshake.This is done by storing secret information such as session ID of the previous sessions and using them when both parties connect with each other in future.

3)Static RSA and Diffie-Hellman cipher suites have been removed; all public-key based key exchange mechanisms now provide forward secrecy.

The SSL labs has already implemented a Penalty for not using forward secrecy in its scoring system ,if the website doesn't implement PFS.

4)All handshake messages after the ServerHello are now encrypted.The newly introduced EncryptedExtension message allows various extensions previously sent in clear in the ServerHello to also enjoy confidentiality protection from active attackers.

Also TLSv1.3 discontinued the support for obsolete ciphers and algorithms. That list includes the following major cryptographic standards/algorithms.

RC4 Steam Cipher
RSA Key Transport
SHA-1 Hash Function
CBC Mode Ciphers
MD5 Algorithm
Various Diffie-Hellman groups
EXPORT-strength ciphers
DES
3DES

You can read the complete IETF document @ https://tools.ietf.org/html/draft-ietf-tls-tls13-28

Download Microsoft Office 2019 offline installer.

When you do malware analysis of documents or office files, it is important to have Microsoft Office installed in your Lab machine. I am using flare VM and it doesn't comes with MS Office. Since Microsoft is promoting Microsoft 365 over the offline version, finding the offline installer is not that easy. Here is the list of genuine Microsoft links to download the office .img files. Download Microsoft Office 2019 Professional Plus : https://officecdn.microsoft.com/db/492350F6-3A01-4F97-B9C0-C7C6DDF67D60/media/en-US/ProPlus2019Retail.img Download Microsoft Office 2019 Professional : https://officecdn.microsoft.com/db/492350F6-3A01-4F97-B9C0-C7C6DDF67D60/media/en-US/Professional2019Retail.img Download Microsoft Office 2019 Home and Business : https://officecdn.microsoft.com/db/492350F6-3A01-4F97-B9C0-C7C6DDF67D60/media/en-US/HomeBusiness2019Retail.img Download Microsoft Office 2019 Home and Student : https://officecdn.microsoft.com/db/492350F6-3A01-4F97-B9C0-C7C6DDF67D60/media/en-U...

RUST error: linker `link.exe` not found

While compiling Rust program in a windows environment, you may encounter the error : linker `link.exe` not found. This is because of the absence of the C++ build tools in your machine. For compiling Rust programs successfully, one of the prerequisites is the installation of the Build Tools for Visual Studio 2019. Download the Visual Studio 2019 Build tools from the Microsoft website. After the download, while installing the Build tools, make sure that you install the required components (highlighted in Yellow) This will download around 1.2GB of required files. Once everything is successfully installed, reboot and re-run your rust program and it will compile successfully. Read More on RUST Hello World Rust Program : Code explained RUST Cargo Package Manager Explained Data Representation in Rust.

Cisco ASA: Disable SSLv3 and configure TLSv1.2.

For configuring TLS v1.2, the ASA should run software version 9.3(2) or later. In earlier versions of ASA, TLS 1.2 is not supported.If you are running the old version, it's time to upgrade. But before that i will show you the config prior to the change. I am running ASA version 9.6.1 Now ,set the server-version to tlsv1.2, though ASA supports version tlsv1.1, its always better to configure the connection to more secure. Server here in the sense, the ASA will be act as the server and the client will connect to the ASA. #ssl server-version tlsv1.2 set the client-version to tlsv1.2, if required. #ssl client-version tlsv1.2 ssl cipher command in ASA offers 5 predefined security levels and an additional custom level. #ssl cipher tlsv1.2 high we can see the setting of each cipher levels using #show ssl cipher command. Now set the DH group to 24, which is the strongest offered as of now in the AS...

How to Install Netmiko on Windows?

Netmiko, developed by kirk Byers is an open source python library based on Paramiko which simplifies SSH management to network devices and is primarily used for network automation tasks. Installing Netmiko in linux is a matter o f one single command but if you need to use Netmiko in your Windows PC, follow this process. 1) Install the latest version of Python. 2) Install Anaconda, which is an opensource distribution platform that you can install in Windows and other OS's (https://www.anaconda.com/download/) 3) From the Anaconda Shell, run “ conda install paramiko ”. 4) From the Anaconda Shell, run “ pip install scp ”. 5) Now Install the Git for Windows. (https://www.git-scm.com/downloads) . Git is required for downloading and cloning all the Netmiko library files from Github. 6) From Git Bash window, Clone Netmiko using the following command git clone https://github.com/ktbyers/netmiko&#8221 7) Onc...

Recovery Procedure: Alcatel-Lucent Omni-Switch not booting AOS: Going to Mini-boot prompt.

Problem: Switch not booting AOS; Going to Mini-boot prompt. Model: Alcatel-Lucent OS6850 [Note:The same procedure might be applicable for different models of Omni-Switches, However, for this illustration, i have used OS-6850 ] Reason: This problem may occurs due to corrupt AOS image files or misconfigured boot parameters. Hence switch cannot boot the images properly and will go to Mini-boot prompt. Work Around: [Note: This zmodem procedure consumes a lot to time to finish the process.] 1.) Power off your OS6850 2.) When you switched it back on, stop it before the Miniboot (there is some counter counting down from 4). Press Enter to break. 3.) You will have the following prompt " => " 4.) Enter " setenv baudrate 115200 ”. Increasing baudrate helps to increase the data transfer speed using zmodem. 5.) Enter " saveenv " 6.) Enter " boot " 7.) The switch should run now in baud rate 115200 (so you have to change your clients ter...

[FIX] yt_dlp.utils.DownloadError: ERROR: You have requested merging of multiple formats but ffmpeg is not installed

[ISSUE] While running your python code or while executing a job : yt_dlp.utils.DownloadError: ERROR: You have requested merging of multiple formats but ffmpeg is not installed [CAUSE] Your code is unable to find ffmpeg installed in your system. [FIX] Install ffmpeg in your system. 1) Download ffmpeg package from Git or already compiled executable from the official website . 2) Once downloaded, extract the zip file and place it in your desired location. eg: C:\ 3) Now add the ffmpeg bin directory location in the user environment variable path. In the User variables section. Select Path and click on New. Click on New and add the path. Now compile your code and it should work. For the python code to download YouTube playlist, visit https://github.com/jaacostan/YTDL

[FIX] Can't locate Net/SNMP.pm in @INC (you may need to install the Net::SNMP module)

I was trying to use the snmpenum.pl in my lab and encountered this error. Can't locate Net/SNMP.pm in @INC (you may need to install the Net::SNMP module) I searched over the internet for the fix , but couldn't able to find something direct. However, going through some of the stackoverflow pages, i fixed it and is explained below. 1) First install the required packages related to snmp utilities. sudo apt-get install libsnmp-perl 2) Install the SNMP module for perl. perl -MCPAN -e 'install Net::SNMP' That's it. And i was able to run the script.