Obfuscated commands used by threat actors are a challenge for anyone in a defender role. Wietze Beukema created ArgFuscator – https://argfuscator.net/ – an open-source, stand-alone web application that helps generate obfuscated command lines for common system-native executables. The main objective of this project is to document established command-line obfuscation techniques used in cyber attacks and to enable users to create obfuscated command lines. This is a valuable tool for cybersecurity defenders to evaluate their defense systems. Detecting or managing command-line obfuscation doesn’t need to be challenging, and this resource ensures practical, real-world validation of defense strategies within one’s environment.
More about it here:
- https://lnkd.in/gpvVsgbw
- GitHub repo: https://lnkd.in/ghC4_u5Y
Practice Verified Codes and Commands:
1. Basic Command Obfuscation Example:
<h1>Original command:</h1> ipconfig /all <h1>Obfuscated command using ArgFuscator:</h1> cmd.exe /c "set x=ipconf&& call %x%ig /all"
2. PowerShell Obfuscation:
<h1>Original command:</h1> Get-Process <h1>Obfuscated command:</h1> $a = "Get-Process"; Invoke-Expression $a
3. Linux Bash Obfuscation:
<h1>Original command:</h1> ls -la <h1>Obfuscated command:</h1> $(echo "bHM=" | base64 --decode) -la
4. Windows Command Prompt Obfuscation:
[cmd]
:: Original command:
dir C:\
:: Obfuscated command:
for /f “tokens=*” %i in (‘echo dir C:\’) do %i
[/cmd]
5. Detecting Obfuscated Commands with YARA:
[yara]
rule obfuscated_cmd {
strings:
$a = /cmd.exe\s+\/c\s+”.*”/
$b = /powershell\s+-encod/
condition:
$a or $b
}
[/yara]
What Undercode Say:
Command-line obfuscation is a critical technique used by threat actors to evade detection by security systems. Tools like ArgFuscator provide defenders with the ability to simulate these techniques, enabling them to test and improve their defenses. By understanding how obfuscation works, cybersecurity professionals can better detect and mitigate these threats. For instance, using YARA rules or regex patterns to identify suspicious command structures can be highly effective. Additionally, leveraging tools like Sysmon or PowerShell logging can help in monitoring and analyzing command-line activities. Always ensure your systems are updated with the latest security patches and employ robust endpoint detection and response (EDR) solutions. For further reading, explore the ArgFuscator GitHub repository and its documentation to dive deeper into obfuscation techniques and countermeasures. Remember, the key to effective cybersecurity lies in continuous learning and adaptation.
References:
Hackers Feeds, Undercode AI
