DUHK Attack Lets Hackers Recover Encryption Key Used in VPNs & Web Sessions

-

DUHK — Don't Use Hard-coded Keys — is a new 'non-trivial' cryptographic implementation vulnerability that could allow attackers to recover encryption keys that secure VPN connections and web browsing sessions.

DUHK is the third crypto-related vulnerability reported this month after KRACK Wi-Fi attack and ROCA factorization attack.

The vulnerability affects products from dozens of vendors, including Fortinet, Cisco, TechGuard, whose devices rely on ANSI X9.31 RNG — an outdated pseudorandom number generation algorithm — 'in conjunction with a hard-coded seed key.'
Before getting removed from the list of FIPS-approved pseudorandom number generation algorithms in January 2016, ANSI X9.31 RNG was included into various cryptographic standards over the last three decades.

Pseudorandom number generators (PRNGs) don’t generate random numbers at all. Instead, it is a deterministic algorithm that produces a sequence of bits based on initial secret values called a seed and the current state. It always generates the same sequence of bits for when used with same initial values.

Some vendors store this 'secret' seed value hard-coded into the source code of their products, leaving it vulnerable to firmware reverse-engineering.

Discovered by cryptography researchers — Shaanan Cohney, Nadia Heninger, and Matthew Green — DUHK, a 'state recovery attack,' allows man-in-the-middle attackers, who already know the seed value, to recover the current state value after observing some outputs.

Using both values in hand, attackers can then use them to re-calculate the encryption keys, allowing them to recover encrypted data that could 'include sensitive business data, login credentials, credit card data and other confidential content.'

"In order to demonstrate the practicality of this attack, we develop a full passive decryption attack against FortiGate VPN gateway products using FortiOS version 4." researchers said.
"Our scans found at least 23,000 devices with a publicly visible IPv4 address running a vulnerable version of FortiOS."
Here below you can check a partial list (tested by researchers) of affected devices from various vendors:



Comments

Post a Comment

Popular posts from this blog

Avet – Open Source Anti-Virus Evasion Tool

-
Image
When we want to perform an exploitation to a windows target, we need a payload that is undetectable to Antivirus Solutions. Msfvenom on its own is not enough. So we need an AV evasion tool to make this easy for us. Avet is a tool for building exe files with shellcode payloads for antivirus evasion. Installing Avet First clone the repository to our machine. git clone https://github.com/govolution/avet.git   After that go inside the folder and run the setup file to install wine and other missing components. cd avet/       Run the setup file to install the missing components.   ./setup.sh     Select create  for new installation   Running Avet There are two ways to run avet. Run avet by typing the command below. python avet_fabric.py   There are two ways to run avet. Either by compiling the make_avet script as shown below, or by  running the avet_fabric.py scr...
Read more

PDFCrack - Password Cracking Tool for PDF-files

-
Image
PDFcrack is a GNU/Linux tool for cracking password protected PDF files. It is a very small command line application. It is not preinstalled in kali linux. We can install through command line. For installing pdfcrack open a terminal and enter apt install pdfcrack Syntax and options Usage: pdfcrack -f filename [OPTIONS]           : pdfcrack -f filenmae -w passwordfile.txt OPTIONS : -b, --bench perform benchmark and exit -c, --charset=STRING Use the characters in STRING as charset -w, --wordlist=FILE Use FILE as source of passwords to try -n, --minpw=INTEGER Skip trying passwords shorter than this -m, --maxpw=INTEGER Stop when reaching this passwordlength -l, --loadState=FILE Continue from the state saved in FILENAME -o, --owner Work with the ownerpassword -u, --user Work with the userpassword (default) -p, --password=STRING Give userpassword to speed up breaking ownerpassword (...
Read more

How to Repair Kali Linux grub after installing Windows in Dual boot System

-
Image
If your System has primary OS Windows then you install your secondary OS Kali Linux. That will be OK, Kali Linux puts boot entry of Windows automatically for you. At initial boot menu you can see both OS entry to boot. If your windows is corrupt in dual boot system or if you want to install windows as secondary OS after installing Kali Linux as primary OS. You may face corrupt boot-loader menu. You wont be able to boot Kali Linux any more because Windows wont put entry of Kali Linux automatically in their boot menu. So this post motive is to help those guys which are facing those problems subjecting to corrupt Boot-loader. There are mainly two methods: 1. Repair Grub via Kali Linux live USB. 2. Repair Grub Via Boot-rapair-disk. Method 1# Repair Grub via Kali Linux live USB It is up to you which you want to choose but if you are Linux familiar then go for this method. Requirements 1. A Kali Linux ISO image. You can download here: Download Kali Linux...
Read more