Creating Shellcodes with Venom: A Comprehensive Guide
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Chapter 1: Introduction to Venom
Venom serves as a powerful script that utilizes msfvenom to generate shellcode in multiple formats, including C, Python, Ruby, DLL, MSI, and HTA-PSH. This script is designed to inject the generated shellcode into a specified template, such as a Python framework. The Python function executes the shellcode in RAM, leveraging compilers like GCC (GNU Cross Compiler), MinGW32, or PyInstaller to create the executable file. Additionally, Venom initiates a multi-handler to accept remote connections.
To illustrate the capabilities of Venom, you can check out this video that explains its functionalities in detail.
Section 1.1: Setting Up Venom
Venom is specifically engineered to work with the Apache2 web server, allowing the distribution of payloads over a local area network (LAN) through a deceptive HTML webpage. This page utilizes elements like <iframe> and <form> tags to facilitate the downloading of payloads. The target simply needs to click the provided link.
Subsection 1.1.1: Generating Shellcode
By default, Venom offers seven different methods for generating shellcode. For this demonstration, we will choose the option "3 — Multi-OS payloads," which allows the creation of shellcode compatible with various operating systems. Following this, a list of available agents will appear, and we will select option "2" to generate Java-based shellcode.
After confirming your selection, you will be prompted to enter the LHOST (the attacker's IP address) and the desired port number in the LPORT field. You can name your shellcode as you prefer and click "OK."
The subsequent screen will present a list of available payloads. The default selection will typically align with the chosen agent, but you have the option to select any other payload as well. Once your backdoor is created, it will be saved in the "opt/venom/output/" directory.
Section 1.2: Delivery Methods
Venom offers two primary methods for delivering your backdoor. The first method creates a multi-handler listener to await incoming connections, requiring manual delivery of the backdoor. The second method initiates the Apache2 server and generates a malicious URL, which you can send to your victim to entice them into clicking the link. Given the simplicity of the first method, which we have previously covered, we will focus on the second option.
Next, choose any available post-exploitation module and click "OK." Venom will generate a malicious link, such as "http://10.10.10.4," and automatically start the multi-handler for you. You might want to use online services to modify the URL to appear more trustworthy.
Once the malicious URL is sent to the target and executed on their computer, the shellcode will run, and a reverse shell connection will be established with the attacker's machine, as depicted in the screenshots below.
Chapter 2: Conclusion and Applications
Venom stands out as an effective payload generator and exploiter, allowing users to leverage advanced tools such as Metasploit. Many payloads created with Venom have the capability to bypass even the most sophisticated antivirus programs.
To see practical applications of Venom in action, check out this informative video.