If you're able to set arbitrary environment variables, then you could also emulate the prefix and suffix. e.g. this works even on patched F20: $ env 'BASH

If you're able to set arbitrary environment variables, then you could also emulate the prefix and suffix. e.g. this works even on patched F20: $ env 'BASH_FUNC_ls()=() { echo myls; }' bash -c ls myls But as others mention, this is not really a bash issue anymore, rather a general problem of sanitizing environments.