I always wondered how useful such tools are against a competent adversary. If you are a competent engineer designing malware, wouldn't you introduce a dormancy period into your malware executable and if possible only talk to C&C while the user is doing something that talks to other endpoints? Maybe even choose the communication protocol based on what the user is doing to blend in even better.
At the very least, these tools should not parse /proc to obtain information of processes or connections. It should be the last option. Many LD_PRELOAD rootkits hide their activity from the system by manipulating the output of libc functions like readdir(), open(), stat(), etc. kernel rootkits can hide whatever they need, but the common functionality is also to hide data from /proc. That's why netstat, ps, *top or lso…
In any case, interesting to think of shared libraries (specifically shared libc) as a risk here. Makes sense, but I hadn't thought about it before.
That said, I'm having a hard time doing a threat model where you worry about an attacker only setting LD_PRELOAD but not modifying PATH. The latter is more general and can screw you with all programs (doesn't cover shell builtins, but it's not like those would just be one more step).