Show HN: TheProtector – Linux Bash script for the paranoid admin on a budget

I love this implementation approach.

At first glance I questioned your choice of bash over something like Python, but you're right - bash is everywhere and every competent Linux admin knows how to use it. There's a zillion unprotected Linux servers out there where this would be very handy.

In terms of next steps, it might be worth documenting more about the notification framework and some simple examples of how we might use it. I can see you've mentioned integrations with email, Slack and webhooks in the tech paper, but I can't spot anything about how to use them

Congratulations on a really worthy project

This cannot conscientiously be called a security tool, as it lacks:

- author attribution (in fact, a mockery is made of it)

- qualified independent security review and endorsement

- designs justifying irrational decisions such as unilateral superuser execution

- any sort of testing, validation or significant documentation of code functionality

- steps to undo whatever this does (since anything is possible, as all liability is explicitely disavowed)

This is not meant to discourage development, but such software should have a clear an EXPERIMENTAL disclaimer and not purport to secure anything; primum non nocere.

As someone who runs production services but isn't a full-time sysadmin, I evaluated this script before thinking about deploying it.

Here's what you should know:

The Good: It's a comprehensive monitoring solution that actually catches real threats. The YARA integration, eBPF monitoring, and honeypot features are impressive for a bash script.

Security Issues:

1. Command injection in process monitoring - Initially looked like a vulnerability because the code uses xargs basename on process names, which seemed dangerous. However, process names from ps output are already sanitized by the kernel (limited to 15 chars, no shell metacharacters executed).

2. Executing Python scripts from /tmp as root - Real privilege escalation vulnerability. Ghost Sentinel writes to world-writable /tmp then executes as root. Any local user can overwrite the file between write and execute to gain root. Trivial to exploit with inotify or loop, 100% reliable. Turns any compromised service account into root access. Fix: use root-owned directory instead of /tmp.

Email Configuration - Gmail will block direct server emails. Install msmtp and configure it with your Gmail app password (not regular password) to get theProtector to use msmtp's mail command:

  # Install
  sudo apt-get install msmtp msmtp-mta
  
  # Configure ~/.msmtprc (for root since script runs as root)
  sudo tee /root/.msmtprc << 'EOF'
  defaults
  auth           on
  tls            on
  tls_trust_file /etc/ssl/certs/ca-certificates.crt
  account        gmail
  host           smtp.gmail.com
  port           587
  from           your-email@gmail.com
  user           your-email@gmail.com
  password       your-app-password
  account default : gmail
  EOF
  
  sudo chmod 600 /root/.msmtprc

Uninstall TheProtector:

  # Remove cron job
  crontab -l | grep -v ghost_sentinel | crontab -
  
  # Remove systemd timer (if installed)
  sudo systemctl disable ghost-sentinel.timer 2>/dev/null
  
  # Remove logs and data
  sudo rm -rf /var/log/ghost-sentinel

Auto-update concerns: The script does NOT auto-update. self_update() only runs when you explicitly execute ./the_protector.sh update

Performance note: On resource-constrained VPS instances, set ENABLE_EBPF=false and MAX_FIND_DEPTH=1

I'm deploying a patched version this week. The creator spent a year on this and it shows - the eBPF/YARA integration is impressive. They should set up GitHub Sponsors or a donation link. It's better than many commercial solutions I've seen.

I would probably delete the self_update function[0] if I were to use this, otherwise this is cool!

https://github.com/IHATEGIVINGAUSERNAME/theProtector/blob/ma...

Neat, but isn't packing all this stuff into a bash script overkill? You can pretty easily install and configure some good tools (i.e. crowdsec, rkhunter, ssh tarpit or whatever) to cover each of the categories rather than have a bunch of half-measures.

Also, you're calling this TheProtector, but internally it seems to be called ghost sentinel?

> local update_url="https://raw[dot]githubusercontent[dot]com/your-repo/ghost-se..."

Would love to see the prompts used. I can tell from the formatting etc this is AI built, nothing wrong with that.

This is great. I'm currently trying to use Linux more due to Recall but in terms of security I'm just not sure what I'm doing most of the time. I suppose I should go read a book about it. Any suggestions on that front? Anyway, a tool like this (if trustworthy) would go a long way to helping me in this area. Also I do like that its in bash and not compiled.

Congratulations on your release! That packs a lot of functionality in a surprisingly small and readable (and thus auditable) shell script. Great work!

One thing though: I can imagine you being rather anonymous (no real name, new HN account, new GitHub account) might make people a bit nervous around a security tool. You probably have good reasons for that, but if not.. you might want to reconsider and take credit?

Thanks for all the comments and feedback - the one I run is plugged - has a brain - and can hook - Ill update in a few days with some of the features - if curious and I run a handle name because it would not take much to be more

Really cool and interesting, good work.

I really like the simplicity. I have added it to a test server and will see how it goes. Congrats on releasing your project.

"Built by thelotus over a year of free time. Maintained by thelotus. Given away free because expensive security theater is stupid." Who / what is the lotus?

Was this made with LLMs?

I will check this out, I love the idea.