EXOCET - AV-evading, Undetectable, Payload Delivery Tool

EXOCET is superior to Metasploit's "Evasive Payloads" modules as EXOCET uses AES-256 in GCM Mode (Galois/Counter Mode). Metasploit's Evasion Payloads uses a easy to detect RC4 encryption. While RC4 can decrypt faster, AES-256 is much more difficult to ascertain the intent of the malware.

However, it is possible to use Metasploit to build a Evasive Payload, and then chain that with EXOCET. So EXOCET will decrypt via AES-256, and then the Metasploit Evasive Payload then decrypts itself from RC4.

Much like my previous project, DarkLordObama, this toolkit is designed to be a delivery/launch vehicle, much like Veil-Evasion does.

Dark Lord Obama Project

However, EXOCET is not limited to a single codebase or platforms that are running Python. EXOCET works on ALL supported platforms and architectures that Go supports.

Exocet Overview

EXOCET, is effectively a crypter-type malware dropper that can recycle easily detectable payloads like WannaCry, encrypt them using AES-GCM (Galois/Counter Mode), which is more secure than AES-CBC, and then create a dropper file for a majority of architectures and platforms out there.

Basically...

1. It ingests dangerous malware that are now detectable by antivirus engines
2. It then encrypts them and produces it's own Go file
3. Then that Go file can be cross-compiled to 99% of known architectures
4. Upon execution, the encrypted payload is written to the disk and immediately executed on the command line
5. Alternatively, instead of a file-drop, it will execute the reconstitute shellcode in memory using amenzhinsky's go-memexec module github.com/amenzhinsky/go-memexec
6. A custom shellcode executor is in the works, it takes ordinary C shellcode and after num-transform, it will run it by creating a new process after allocating the correct virtual address space and granting it RWX permissions on Windows

That means 32-bit, and 64-bit architectures, and it works on Linux, Windows, Macs, Unix, Android, iPhone, etc. You take, anything, and I mean ANYTHING, like the 1988 Morris Worm that nearly brought down the internet (which exploited a flaw in the fingerd listener daemon on UNIX), and make it a viable cyberweapon again.

EXOCET is designed to be used with the DSX Program, or the "Cyber Metal Gear" as I envisioned it. Being able to launch and proliferate dangerous malware without a traceable launch trail.

EXOCET is written entirely in Go.

How to use

EXOCET, regardless of which binary you use to run it, requires Golang to work. By default, it generates a crypter .go file.

1. Windows users: Install Go Here
2. Linux users: run sudo apt-get update && sudo apt-get install -y golang
3. You must install the EXOCET source files in golang go get github.com/tanc7/EXOCET-AV-Evasion
4. Sub-requirements will also be downloaded and installed
5. For Windows and Mac x64 Users, pre-compiled binaries are in the /bin folder

To run it

go run EXOCET.go detectablemalware.exe outputmalware.go

A key is automatically generated for you. The key is 64-characters long and is entirely composed of bash and cmd.exe shell pipe redirectors to confuse and disrupt brute-forcing attempts against the key by causing unpredictable, destructive behavior on the forensic analyst's device.

For 64-bit Windows Targets...

env GOOS=windows GOARCH=amd64 go build -ldflags "-s -w" -o outputMalware.exe outputmalware.go

And out comes a outputmalware.exe file

For 64-bit MacOS Targets

env GOOS=darwin GOARCH=amd64 go build -ldflags "-s -w" -o outputMalware.macho outputmalware.go

For 64-bit Linux Targets

env GOOS=linux GOARCH=amd64 go build -ldflags "-s -w" -o outputMalware.elf outputmalware.go

See this reference on github for your parameters for other operating systems like Android Reference for Go Cross Compilation

Note that the key can still be found with the strings command, please use the upx-ucl command to pack binary to conceal the key.

Furthermore, there are prebuilt binaries that I have made, meaning you just have to run ./EXOCET or EXOCET-Windows.exe

Legal Information

I, Chang Tan, and the creators of the main module and submodules of Exocet and the packages it incorporates are NOT responsible for the misuse of this tool. This is merely a penetration testing tool. You are strictly prohibited from deploying Exocet output binaries against unauthorized protected systems or unauthorized protected government systems.

I am aware that threat actors of APT41 and the NSO Group have used and/or adopted code from this tool, particularly the go-memexec method. If I were to be approached by Federal Investigators regarding the misuse of this tool, I am not claiming responsibility.

This is the same stuff that happened to the developers of Mimikatz and PowerShell Empire (who deprecated their own development upon realization of its use among threat actors). The successors have picked up development of Empire, and there are free alternatives such as Covenant C2.

EXOCET live demo
<iframe width="560" height="315" src="https://github.com/tanc7/EXOCET-AV-Evasion/blob/master/media/exocetdemo.mp4" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
Reason for the name

On May 4th, 1982, during the Falklands War, a squadron of Argentinan Super Eterdards launched a French made Exocet missile at the HMS Sheffield. Despite the Royal Navy's attempts to stop the missile, one struck, sinking the Sheffield. That incident literally put Argentina on the map as a show of force against a global colonial power.

News Article of the sinking of the HMS Sheffield

Very much like how Onel de Guzman's actions with the ILOVEYOU virus put the Philippines on the map as a cyber threat.

ILOVEYOU Virus on Wikipedia

Incoming update, notes and ambitions

 

So this month, and the next month is going to be a busy month for me, and there will be delays in implementing these methods. But I am excited to get started on implementing new AV evasion techniques such as...

1. Inline hooking
2. Obfuscation by emulating BlackRota and the gobfuscate module
3. Process hollowing
4. Reflective DLL injection
5. Remote process injection
6. ThreadLocalStorage Callbacks
7. Registration of Top-Level Exception Handlers
8. Custom UPX packing

I am a very busy man, I have the following priorities and I would like to request some help, some pull requests to aid in the project. Since I have the following things to do

1. A court appearance in late October
2. National Cyber League
3. Accounting and Finance Classes, Computer Science was NEVER my college major and in the following weeks I will have exams back-to-back
4. Federal Supervised Release Conditions and the FBI trying to implicate me in new unproven crimes. I have dash camera videos I uploaded to the cloud to prove it that I am sending to my lawyers. I have documented multiple attacks against me, vandalism of my car, my house, filed police reports and counter reports and will be building my case to file a Federal lawsuit. One of the perpetrators, who ripped out my front bumper of my car, has been arrested.
5. A private project involving interaction with the CoinGeckoAPI
6. Running the cryptoscopeinitiative.org, a to-be-filed 501c3 Non-Profit Organization
7. Teaching three online classes on Exploit Development

Upcoming update! Direct encrypted shellcode execution! (Implemented in test versions, not released yet)

I need a bit of help, because I successfully implemented CGO to execute encrypted shellcode but it is throwing memory access violations exit status 0xc0000005. It shouldn't be anything related to DEP (Data Execution Prevention) because the file CGOTest/working-template-shellcode-executor.go did run.

Problem Discovered

As it turns out, VirtualAlloc must be called from kernel32.dll and ntdll.dll to properly make the memory page where the shellcode lands, readable, writable, and executable, in other word, set the PAGE_EXECUTE_READWRITE to ON. Read the Note on Memory Access Violation Problem below.

Once I figure this out, CGO was a pain in the ass to implement, we can now create crypters that execute INLINE-ASSEMBLY. Which was considered a impossibility until now.

Note this requires Golang and the MinGW toolchain to be installed on Windows with you running and generating the shellcode on Windows. The reason why, is because CGO cannot be cross-compiled like our other EXOCET modules. To install the toolchain you need to go to https://www.msys2.org/ and follow the guide. Then you must add gcc to your environment variables in Windows

Step 1: Generate shellcode, this could be from msfvenom Meterpreter payloads, Cobalt Strike Beacons, or your own custom shellcode in C compatible format

Step 2: Copy only the bytes of the shellcode, excluding the quotes into a text file like sc.txt

Step 3: Your shellcode file should look like this. Raw shellcode

Step 4: Now run the command go run exocet-shellcode-exec.go sc.txt shellcodetest.go KEY

Step 5: You can attempt to run it but you'll run into memory access violation errors for some reason, which I am still working on

Note on Memory Access Violation Problem

Apparently, aside from the major limitations of CGO that prohibit or dramatically frustrates cross-compilation, the issue is that the shellcode we want to execute is landing in a section of memory (analyzed in WinDBG x64) that is not RWX. In other words, unless we write C code that explicitly allows execution in memory of the shellcode, it will always throw access violation errors.

The other method, that I observed other developers of rudimentary Go modules https://gist.github.com/mgeeky/bb0fd5652b234fbd1c7630d7e5c8542d, is that they use Go's Windows API to interact with ntdll.dll and kernel32.dll to call VirtualAlloc and specify areas of RWX memory pages. This method works better, but it seems that the shellcode must be in num-transformed format only for it to work.

I am still working on this you guys. I may combine multiple programming languages together to write a proper shellcode execution module

Note on Apple M1 Chips for precompiled binaries

Unfortunately I am running into errors for making a pre-compiled binary for MacBooks running the new M1 CPUs. It may be a issue with my Golang installation

┌──(root💀kali)-[/opt/EXOCET-AV-Evasion]
└─# GOOS=darwin GOARCH=arm64 go build exocet.go 
# command-line-arguments
/usr/lib/go-1.15/pkg/tool/linux_amd64/link: running gcc failed: exit status 1
/tmp/go-link-477718799/go.o: file not recognized: file format not recognized
collect2: error: ld returned 1 exit status

Either way, you still require Golang to compile or cross-compile the malware to the platform you are targeting.

Download EXOCET-AV-Evasion

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Infineon RSA Vulnerability - ROC

This tool is related to ACM CCS 2017 conference paper #124 Return of the Coppersmith’s Attack: Practical Factorization of Widely Used RSA Moduli.

It enables you to test public RSA keys for a presence of the described vulnerability.

Update: The paper of the attack is already online, ACM version.

Currently the tool supports the following key formats:

• X509 Certificate, DER encoded, one per file, *.der, *.crt
• X509 Certificate, PEM encoded, more per file, *.pem
• RSA PEM encoded private key, public key, more per file, *.pem (has to have correct header -----BEGIN RSA...)
• SSH public key, *.pub, starting with "ssh-rsa", one per line
• ASC encoded PGP key, *.pgp, *.asc. More per file, has to have correct header -----BEGIN PGP...
• APK android application, *.apk
• one modulus per line text file *.txt, modulus can be a) base64 encoded number, b) hex coded number, c) decimal coded number
• JSON file with moduli, one record per line, record with modulus has key "mod" (int, base64, hex, dec encoding supported) certificate(s) with key "cert" / array of certificates with key "certs" are supported, base64 encoded DER.
• LDIFF file - LDAP database dump. Any field ending with ";binary::" is attempted to decode as X509 certificate
• Java Key Store file (JKS). Tries empty password & some common, specify more with --jks-pass-file
• PKCS7 signature with user certificate

The detection tool is intentionally one-file implementation for easy integration / manipulation.

Pip install
Install with pip (installs all dependencies)

pip install roca-detect

Local install
Execute in the root folder of the package:

pip install --upgrade --find-links=. .

Dependencies
It may be required to install additional dependencies so pip can install e.g. cryptography package.
CentOS / RHEL:

sudo yum install python-devel python-pip gcc gcc-c++ make automake autoreconf libtool openssl-devel libffi-devel dialog

Ubuntu:

sudo apt-get install python-pip python-dev build-essential libssl-dev libffi-dev swig

Usage
To print the basic usage:

# If installed with pip / manually
roca-detect --help

# Without installation (can miss dependencies)
python roca/detect.py

The testing tool accepts multiple file names / directories as the input argument. It returns the report showing how many files has been fingerprinted (and which are those).
Example (no vulnerabilities found):
Running recursively on all my SSH keys and known_hosts:

$> roca-detect ~/.ssh
2017-10-16 13:39:21 [51272] INFO ### SUMMARY ####################
2017-10-16 13:39:21 [51272] INFO Records tested: 92
2017-10-16 13:39:21 [51272] INFO .. PEM certs: . . . 0
2017-10-16 13:39:21 [51272] INFO .. DER certs: . . . 0
2017-10-16 13:39:21 [51272] INFO .. RSA key files: . 16
2017-10-16 13:39:21 [51272] INFO .. PGP master keys: 0
2017-10-16 13:39:21 [51272] INFO .. PGP total keys:  0
2017-10-16 13:39:21 [51272] INFO .. SSH keys:  . . . 76
2017-10-16 13:39:21 [51272] INFO .. APK keys:  . . . 0
2017-10-16 13:39:21 [51272] INFO .. JSON keys: . . . 0
2017-10-16 13:39:21 [51272] INFO .. LDIFF certs: . . 0
2017-10-16 13:39:21 [51272] INFO .. JKS certs: . . . 0
2017-10-16 13:39:21 [51272] INFO .. PKCS7: . . . . . 0
2017-10-16 13:39:21 [51272] INFO No fingerprinted keys found (OK)
2017-10-16 13:39:21 [51272] INFO ################################

Example (vulnerabilities found):
Running recursively on all my SSH keys and known_hosts:

$> roca-detect ~/.ssh
2017-10-16 13:39:21 [51272] WARNING Fingerprint found in the Certificate
...
2017-10-16 13:39:21 [51272] INFO ### SUMMARY ####################
2017-10-16 13:39:21 [51272] INFO Records tested: 92
2017-10-16 13:39:21 [51272] INFO .. PEM certs: . . . 0
2017-10-16 13:39:21 [51272] INFO .. DER certs: . . . 0
2017-10-16 13:39:21 [51272] INFO .. RSA key files: . 16
2017-10-16 13:39:21 [51272] INFO .. PGP master keys: 0
2017-10-16 13:39:21 [51272] INFO .. PGP total keys:  0
2017-10-16 13:39:21 [51272] INFO .. SSH keys:  . . . 76
2017-10-16 13:39:21 [51272] INFO .. APK keys:  . . . 0
2017-10-16 13:39:21 [51272] INFO .. JSON keys: . . . 0
2017-10-16 13:39:21 [51272] INFO .. LDIFF certs: . . 0
2017-10-16 13:39:21 [51272] INFO .. JKS certs: . . . 0
2017-10-16 13:39:21 [51272] INFO .. PKCS7: . . . . . 0
2017-10-16 13:39:21 [51272] INFO Fingerprinted keys found: 1
2017-10-16 13:39:21 [51272] INFO WARNING: Potential vulnerability
2017-10-16 13:39:21 [51272] INFO ################################

PGP key
In order to test your PGP key you can export it from your email client or download it from the PGP key server such as https://pgp.mit.edu/
You can also use gpg command line utility to export your public key:

gpg --armor --export [email protected] > mykey.asc

Advanced use case
Detection tool extracts information about the key which can be displayed:

roca-detect.py --dump --flatten --indent  ~/.ssh/

Advanced installation methods

Virtual environment
It is usually recommended to create a new python virtual environment for the project:

virtualenv ~/pyenv
source ~/pyenv/bin/activate
pip install --upgrade pip
pip install --upgrade --find-links=. .

Separate Python 2.7.13
We tested tool with Python 2.7.13 and it works (see Travis for more info). We have reports saying lower versions (<=2.6) do not work properly so we highly recommend using up to date Python 2.7
Use pyenv to install a new Python version locally if you cannot / don't want to update system Python.
It internally downloads Python sources and installs it to ~/.pyenv.

git clone https://github.com/pyenv/pyenv.git ~/.pyenv
echo 'export PYENV_ROOT="$HOME/.pyenv"' >> ~/.bashrc
echo 'export PATH="$PYENV_ROOT/bin:$PATH"' >> ~/.bashrc
echo 'eval "$(pyenv init -)"' >> ~/.bashrc
exec $SHELL
pyenv install 2.7.13
pyenv local 2.7.13

Python 3
Basic testing routine is quite simple and works with Py3 but the rest of the code that processes the different key formats and extracts the modulus for inspection is not yet fully py3 ready.
We are working on Py3 compatible version.

Docker container
Run via Docker container to avoid environment inconsistency. Dockerfile source can be audited at https://hub.docker.com/r/unnawut/roca-detect/.

docker run --rm -v /path/to/your/keys:/keys --network none unnawut/roca-detect

Make sure to use --rm and --network none flags to disable container's network connection and delete the container after running.

Download ROCA

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The Cyber Swiss Army Knife [A Web App For Encryption, Encoding, Compression And Data Analysis] - CyberChef

The Cyber Swiss Army Knife

CyberChef is a simple, intuitive web app for carrying out all manner of "cyber" operations within a web browser. These operations include simple encoding like XOR or Base64, more complex encryption like AES, DES and Blowfish, creating binary and hexdumps, compression and decompression of data, calculating hashes and checksums, IPv6 and X.509 parsing, changing character encodings, and much more.

The tool is designed to enable both technical and non-technical analysts to manipulate data in complex ways without having to deal with complex tools or algorithms. It was conceived, designed, built and incrementally improved by an analyst in their 10% innovation time over several years. Every effort has been made to structure the code in a readable and extendable format, however it should be noted that the analyst is not a professional developer.

Live demo

CyberChef is still under active development. As a result, it shouldn't be considered a finished product. There is still testing and bug fixing to do, new features to be added and additional documentation to write. Please contribute!

Cryptographic operations in CyberChef should not be relied upon to provide security in any situation. No guarantee is offered for their correctness.

A live demo can be found here - have fun!

How it works

There are four main areas in CyberChef:

1. The input box in the top right, where you can paste, type or drag the data you want to operate on.
2. The output box in the bottom right, where the outcome of your processing will be displayed.
3. The operations list on the far left, where you can find all the operations that CyberChef is capable of in categorised lists, or by searching.
4. The recipe area in the middle, where you can drag the operations that you want to use and specify arguments and options.

You can use as many operations as you like in simple or complex ways. Some examples are as follows:

• Decode a Base64-encoded string
• Convert a date and time to a different time zone
• Parse a Teredo IPv6 address
• Convert data from a hexdump, then decompress
• Display multiple timestamps as full dates
• Carry out different operations on data of different types

Features

• Drag and drop
  • Operations can be dragged in and out of the recipe list, or reorganised.
  • Files can be dragged over the input box to load them directly.
• Auto Bake
  • Whenever you modify the input or the recipe, CyberChef will automatically “bake” for you and produce the output immediately.
  • This can be turned off and operated manually if it is affecting performance (if the input is very large, for instance).
  • If any bake takes longer than 200 milliseconds, auto bake will be switched off automatically to prevent further performance issues.
• Breakpoints
  • You can set breakpoints on any operation in your recipe to pause execution before running it.
  • You can also step through the recipe one operation at a time to see what the data looks like at each stage.
• Save and load recipes
  • If you come up with an awesome recipe that you know you’ll want to use again, just click save and add it to your local storage. It'll be waiting for you next time you visit CyberChef.
  • You can also copy a URL which includes your recipe and input which can be shared with others.
• Search
  • If you know the name of the operation you want or a word associated with it, start typing it into the search field and any matching operations will immediately be shown.
• Highlighting
  • When you highlight text in the input or output, the offset and length values will be displayed and, if possible, the corresponding data will be highlighted in the output or input respectively (example: highlight the word 'question' in the input to see where it appears in the output).
• Save to file and load from file
  • You can save the output to a file at any time or load a file by dragging and dropping it into the input field (note that files larger than about 500kb may cause your browser to hang or even crash due to the way that browsers handle large amounts of textual data).
• CyberChef is entirely client-side
  • It should be noted that none of your input or recipe configuration is ever sent to the CyberChef web server - all processing is carried out within your browser, on your own computer.
  • Due to this feature, CyberChef can be compiled into a single HTML file. You can download this file and drop it into a virtual machine, share it with other people, or use it independently on your desktop.

Browser support

CyberChef is built to support

• Google Chrome 40+
• Mozilla Firefox 35+
• Microsoft Edge 14+

Download CyberChef

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Petya Ransomware Spreading Rapidly Worldwide, Just Like WannaCry - News

Watch out, readers! It is ransomware, another WannaCry, another wide-spread attack.

The WannaCry ransomware is not dead yet and another large scale ransomware attack is making chaos worldwide, shutting down computers at corporates, power supplies, and banks across Russia, Ukraine, Spain, France, UK, India, and Europe and demanding $300 in bitcoins.

According to multiple sources, a new variant of Petya ransomware, also known as Petwrap, is spreading rapidly with the help of same Windows SMBv1 vulnerability that the WannaCry ransomware abused to infect 300,000 systems and servers worldwide in just 72 hours last month.

Apart from this, many victims have also informed that Petya ransomware has also infected their patch systems.

"Petya uses the NSA Eternalblue exploit but also spreads in internal networks with WMIC and PSEXEC. That's why patched systems can get hit." Mikko Hypponen confirms, Chief Research Officer at F-Secure.

Petya is a nasty piece of ransomware and works very differently from any other ransomware malware. Unlike other traditional ransomware, Petya does not encrypt files on a targeted system one by one.

Instead, Petya reboots victims computers and encrypts the hard drive's master file table (MFT) and renders the master boot record (MBR) inoperable, restricting access to the full system by seizing information about file names, sizes, and location on the physical disk.

Petya ransomware replaces the computer's MBR with its own malicious code that displays the ransom note and leaves computers unable to boot.

Don't Pay Ransom, You Wouldn’t Get Your Files Back 

Infected users are advised not to pay the ransom because hackers behind Petya ransomware can’t get your emails anymore.

Posteo, the German email provider, has suspended the email address i.e. wowsmith123456@posteo.net, which was behind used by the criminals to communicate with victims after getting the ransom to send the decryption keys.

At the time of writing, 23 victims have paid in Bitcoin to '1Mz7153HMuxXTuR2R1t78mGSdzaAtNbBWX' address for decrypting their files infected by Petya, which total roughly $6775.

Petya! Petya! Another Worldwide Ransomware Attack

Screenshots of the latest Petya infection, shared on Twitter, shows that the ransomware displays a text, demanding $300 worth of Bitcoins. Here's what the text read:

"If you see this text, then your files are no longer accessible, because they are encrypted. Perhaps you are busy looking for a way to recover your files, but don't waste your time. Nobody can recover your files without our decryption service."

According to a recent VirusTotal scan, currently, only 16 out of 61 anti-virus services are successfully detecting the Petya ransomware malware.

Petya Ransomware Hits Banks, Telecom, Businesses & Power Companies

Supermarket in Kharkiv, East Ukraine

Petya ransomware has already infected — Russian state-owned oil giant Rosneft, Ukrainian state electricity suppliers, "Kyivenergo" and "Ukrenergo," in past few hours.

"We were attacked. Two hours ago, we had to turn off all our computers. We are waiting for permission from Ukraine's Security Service (SBU) to switch them back on," Kyivenergo's press service said.

There are reports from several banks, including National Bank of Ukraine (NBU) and Oschadbank, as well as other companies confirming they have been hit by the Petya ransomware attacks.

Maersk, an international logistics company, has also confirmed on Twitter that the latest Petya ransomware attacks have shut down its IT systems at multiple locations and business units.

"We can confirm that Maersk IT systems are down across multiple sites and business units. We are currently asserting the situation. The safety of our employees, our operations and customers' business is our top priority. We will update when we have more information," the company said.

The ransomware also impacts multiple workstations at Ukrainian branch's mining company Evraz.

The most severe damages reported by Ukrainian businesses also include compromised systems at Ukraine's local metro and Kiev's Boryspil Airport.

Three Ukrainian telecommunication operators, Kyivstar, LifeCell, Ukrtelecom, are also affected in the latest Petya attack.

How Petya Ransomware Spreading So Fast?

Symantec, the cyber security company, has also confirmed that Petya ransomware is exploiting SMBv1 EternalBlue exploit, just like WannaCry, and taking advantage of unpatched Windows machines.

"Petya ransomware successful in spreading because it combines both a client-side attack (CVE-2017-0199) and a network based threat (MS17-010)," security researcher using Twitter handle ‏HackerFantastic tweeted.

EternalBlue is a Windows SMB exploit leaked by the infamous hacking group Shadow Brokers in its April data dump, who claimed to have stolen it from the US intelligence agency NSA, along with other Windows exploits.

Microsoft has since patched the vulnerability for all versions of Windows operating systems, but many users remain vulnerable, and a string of malware variants are exploiting the flaw to deliver ransomware and mine cryptocurrency.

Just three days ago, we reported about the latest WannaCry attack that hit Honda Motor Company and around 55 speed and traffic light cameras in Japan and Australia, respectively.

Well, it is quite surprising that even after knowing about the WannaCry issue for quite a decent amount of time, big corporates and companies have not yet implemented proper security measures to defend against such threat.

How to Protect Yourself from Ransomware Attacks

What to do immediately? Go and apply those goddamn patches against EternalBlue (MS17-010) and disable the unsecured, 30-year-old SMBv1 file-sharing protocol on your Windows systems and servers.

Since Petya Ransomware is also taking advantage of WMIC and PSEXEC tools to infect fully-patched Windows computers, you are also advised to disable WMIC (Windows Management Instrumentation Command-line).

Prevent Infection & Petya Kill-Switch

Researcher finds Petya ransomware encrypt systems after rebooting the computer. So if your system is infected with Petya ransomware and it tries to restart, just do not power it back on.

"If machine reboots and you see this message, power off immediately! This is the encryption process. If you do not power on, files are fine." ‏HackerFantastic tweeted. "Use a LiveCD or external machine to recover files"

PT Security, a UK-based cyber security company and Amit Serper from Cybereason, have discovered a Kill-Switch for Petya ransomware. According to a tweet, company has advised users to create a file i.e. "C:\Windows\perfc" to prevent ransomware infection.

To safeguard against any ransomware infection, you should always be suspicious of unwanted files and documents sent over an email and should never click on links inside them unless verifying the source.

To always have a tight grip on your valuable data, keep a good back-up routine in place that makes their copies to an external storage device that isn't always connected to your PC.

Moreover, make sure that you run a good and effective anti-virus security suite on your system, and keep it up-to-date. Most importantly, always browse the Internet safely.

Source: The Hacker News

OffensiveSec

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WannaCry Ransomware Decryption Tool - WanaKiwi

If your PC has been infected by WannaCry – the ransomware that wreaked havoc across the world last Friday – you might be lucky to get your locked files back without paying the ransom of $300 to the cyber criminals.

Adrien Guinet, a French security researcher from Quarkslab, has discovered a way to retrieve the secret encryption keys used by the WannaCry ransomware for free, which works on Windows XP, Windows 7, Windows Vista, Windows Server 2003 and 2008 operating systems.

WannaCry Ransomware Decryption Keys

The WannaCry's encryption scheme works by generating a pair of keys on the victim's computer that rely on prime numbers, a "public" key and a "private" key for encrypting and decrypting the system’s files respectively.
To prevent the victim from accessing the private key and decrypting locked files himself, WannaCry erases the key from the system, leaving no choice for the victims to retrieve the decryption key except paying the ransom to the attacker.

But here's the kicker: WannaCry "does not erase the prime numbers from memory before freeing the associated memory," says Guinet.

Based on this finding, Guinet released a WannaCry ransomware decryption tool, named WannaKey, that basically tries to retrieve the two prime numbers, used in the formula to generate encryption keys from memory, and works on Windows XP only.

Note: Below I have also mentioned another tool, dubbed WanaKiwi, that works for Windows XP to Windows 7.

"It does so by searching for them in the wcry.exe process. This is the process that generates the RSA private key. The main issue is that the CryptDestroyKey and CryptReleaseContext does not erase the prime numbers from memory before freeing the associated memory." says Guinet

So, that means, this method will work only if:

• The affected computer has not been rebooted after being infected.
• The associated memory has not been allocated and erased by some other process.

"In order to work, your computer must not have been rebooted after being infected. Please also note that you need some luck for this to work (see below), and so it might not work in every case!," Guinet says.

"This is not really a mistake from the ransomware authors, as they properly use the Windows Crypto API."
While WannaKey only pulls prime numbers from the memory of the affected computer, the tool can only be used by those who can use those prime numbers to generate the decryption key manually to decrypt their WannaCry-infected PC’s files.

WanaKiwi: WannaCry Ransomware Decryption Tool

Good news is that another security researcher, Benjamin Delpy, developed an easy-to-use tool called "WanaKiwi," based on Guinet's finding, which simplifies the whole process of the WannaCry-infected file decryption.

All victims have to do is download WanaKiwi tool from Github and run it on their affected Windows computer using the command line (cmd).

WanaKiwi works on Windows XP, Windows 7, Windows Vista, Windows Server 2003 and 2008, confirmed Matt Suiche from security firm Comae Technologies, who has also provided some demonstrations showing how to use WanaKiwi to decrypt your files.

Although the tool won't work for every user due to its dependencies, still it gives some hope to WannaCry's victims of getting their locked files back for free even from Windows XP, the aging, largely unsupported version of Microsoft's operating system.


Source:The Hacker News

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