Show HN: TheProtector – Linux Bash script for the paranoid admin on a budget(github.com)
github.com
Show HN: TheProtector – Linux Bash script for the paranoid admin on a budget
https://github.com/IHATEGIVINGAUSERNAME/theProtector
39 comments
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
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
> bash is everywhere
...except on systems like Alpine Linux and other such minimal distributions.
...except on systems like Alpine Linux and other such minimal distributions.
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:
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.
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 [email protected]
user [email protected]
password your-app-password
account default : gmail
EOF
sudo chmod 600 /root/.msmtprc
# 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
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.
> However, process names from ps output are already sanitized by the kernel (limited to 15 chars, no shell metacharacters executed).
I'm not sure what this is referring to. You can easily create a binary named ' (single quote, a shell meta character) and it will show up in ps (and /proc/pid/cmdline and /proc/pid/status) as a single quote. If you name a binary with a control character, it will show up in ps as ? (a shell metacharacter), and in /proc/$pid/cmdline and /proc/$pid/status as the control character itself (I named a binary as the single ASCII character 7, bell, and catting /proc/$pid/{cmdline,status} plays the as interpreted by the terminal program).
Recent versions of ls display these directory entries quoted for select-and-paste ease as:
Formatted by ls, the ^G file can be given to xargs, and the terminal plays a bell, but the single quote filename can not:
Anyway, you can't trust the content of what ps shows as the commandline pointing to an actual existing binary. The command line isn't always absolute. The best way to find the binary is probably by examining where the symlink /proc/$pid/exe points to, and getting the basename off of that, but that is not guaranteed to be shell-safe either, so YMMV.
I'm not sure what this is referring to. You can easily create a binary named ' (single quote, a shell meta character) and it will show up in ps (and /proc/pid/cmdline and /proc/pid/status) as a single quote. If you name a binary with a control character, it will show up in ps as ? (a shell metacharacter), and in /proc/$pid/cmdline and /proc/$pid/status as the control character itself (I named a binary as the single ASCII character 7, bell, and catting /proc/$pid/{cmdline,status} plays the as interpreted by the terminal program).
Recent versions of ls display these directory entries quoted for select-and-paste ease as:
$ ls -l ? # used ? here to match both files that are a single character
-rwxr-xr-x 2 thwarted thwarted 1769980 Jul 23 19:53 ''$'\a'
-rwxr-xr-x 2 thwarted thwarted 1769980 Jul 23 19:53 "'"
Formatted by ls, the ^G file can be given to xargs, and the terminal plays a bell, but the single quote filename can not:
$ ls -1 /tmp/? | xargs -t -n 1 basename
basename '/tmp/'$'\a'
xargs: unmatched single quote; by default quotes are special to xargs unless you use the -0 option
Anyway, you can't trust the content of what ps shows as the commandline pointing to an actual existing binary. The command line isn't always absolute. The best way to find the binary is probably by examining where the symlink /proc/$pid/exe points to, and getting the basename off of that, but that is not guaranteed to be shell-safe either, so YMMV.
This is why I released it - I am one person and know I need this community to make it something more
Thanks from the community for your insights
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...
https://github.com/IHATEGIVINGAUSERNAME/theProtector/blob/ma...
Wouldn't be a faithful replacement for enterprise tools if it didn't introduce a new "trust us" backdoor into your systems. :P
ha and good catch
"I spent the past year building this in my spare time because I got tired of enterprise security tools that cost $50K/year and don't understand Linux."
You should have written it as a learning opportunity. To think you can replace such tools seems rather arrogant -- Experienced professionals with decades of experience worked on them. You're just 1 person, and it seems like you may be new.
"TheProtector is a comprehensive security monitoring tool that actually runs on the systems we use (Linux) instead of being a Windows-first afterthought. Built it entirely on a $500 laptop because I believe good security shouldn't require unlimited budgets." After reviewing the code it doesn't seem very comprehensive. As some others have pointed out it appears to be mostly AI-generated. Again, as a learning opportunity this isn't a bad exercise, but I also probably wouldn't brag about it being comparable to tools that were made by teams of people who are likely far more knowledgeable when it comes to designing such tools.
"Been running it on my own systems for months. Catches the stuff that matters and doesn't flood you with false positives. If you hate expensive security theater as much as I do, might be worth a look." I should also probably address the elephant in the room: Your github account is only 2 days old (as of this writing). Additionally the initial commit to the repository was made on July 23rd, 2025. Based on the commit history (and based on the files that were committed) it looks like this was created with AI in the span of a couple days.
I'm sure a 'security-minded' individual such as yourself sees the problem here: a monolithic script from some random person on the internet purporting to have developed something to help secure my system... I wouldn't touch it with a 10-foot pole.
Something about this post stinks to me. Smells like somone trying to phish for installs. Seems like something an intelligence agency would do: post something like this in several places hoping somone runs it.
"TheProtector is a comprehensive security monitoring tool that actually runs on the systems we use (Linux) instead of being a Windows-first afterthought. Built it entirely on a $500 laptop because I believe good security shouldn't require unlimited budgets." After reviewing the code it doesn't seem very comprehensive. As some others have pointed out it appears to be mostly AI-generated. Again, as a learning opportunity this isn't a bad exercise, but I also probably wouldn't brag about it being comparable to tools that were made by teams of people who are likely far more knowledgeable when it comes to designing such tools.
"Been running it on my own systems for months. Catches the stuff that matters and doesn't flood you with false positives. If you hate expensive security theater as much as I do, might be worth a look." I should also probably address the elephant in the room: Your github account is only 2 days old (as of this writing). Additionally the initial commit to the repository was made on July 23rd, 2025. Based on the commit history (and based on the files that were committed) it looks like this was created with AI in the span of a couple days.
I'm sure a 'security-minded' individual such as yourself sees the problem here: a monolithic script from some random person on the internet purporting to have developed something to help secure my system... I wouldn't touch it with a 10-foot pole.
Something about this post stinks to me. Smells like somone trying to phish for installs. Seems like something an intelligence agency would do: post something like this in several places hoping somone runs it.
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..."
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..."
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?
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?
This is them taking the credit under the assumed pen name.
The tech paper is LLM trash. Doesn’t bode well for the code, not just because it’s a gigantic bash script..
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Would love to see the prompts used. I can tell from the formatting etc this is AI built, nothing wrong with that.
organically?? thanks though!!
"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?
I hate the idea of hats - I like the idea of the Lotus growing in something dirty but uses the filth in ponds to make something beautiful
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.
Was this made with LLMs?
I believe so, a human programmer would feel ashamed for adding comments like these:
# Stop honeypots
stop_honeypots
# Stop eBPF monitoring
stop_ebpf_monitoring
# Stop API server
stop_api_server
no - some of what you see is the place holders when framing it - I did read a stuff from - The Practice - Blue Team Field Manual - Linux Hardening - UNIX and Linux System Admin - now the the grammar is clean up is slop by Ollama Llama 3 - I framed into a gui
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
I really like the simplicity. I have added it to a test server and will see how it goes.
Congrats on releasing your project.
same - not perfect and just a start and see how the community can add to it!
What's up with the "tech paper"? It's completely packed with nonsense claims
It's LLM slop. I have done enough of these "projects" with every major model over the last six weeks to recognize it instantly. There are non-subtle patterns I would enumerate if I weren't quite this tired.
[deleted]
Fair - the write up could def be cleaner and was corrected using Ollama I framed in. The bash is not slop and why I use a another name - I do not want to get wrapped up in formatting vs function - in the spirit of open source here - make it better and fully anticipating I would get comments - honestly - I do not have the skill set (or desire) to strip LLM of guard rails - it was fun and worked on it for sometime - I work database and front end and rebuild radios (part time) in the real world and needed something for a personal project/goal
A self-contained Bash script and short enough to evaluate thoroughly in an hour or two. Bravo, OP.
Really cool and interesting, good work.
thanks - it is still a work in progress but please add to it but needed the community to evolve it
I will check this out, I love the idea.
thanks - enjoy and take it to the next level - share it
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.
- 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.
I do not disagree and wanted to keep it true to the linux community and thought - "these guys can make it better and improve at the cost of time versus $$" add to it and improve it
[deleted]
I spent the past year building this in my spare time because I got tired of enterprise security tools that cost $50K/year and don't understand Linux.
TheProtector is a comprehensive security monitoring tool that actually runs on the systems we use (Linux) instead of being a Windows-first afterthought. Built it entirely on a $500 laptop because I believe good security shouldn't require unlimited budgets.
Features: - Real-time process, network, and file monitoring - YARA malware detection with custom rules - eBPF kernel monitoring (when available) - Behavioral baseline establishment and anomaly detection - Active threat response (blocks IPs, kills processes, quarantines files) - Anti-evasion detection for rootkits and advanced threats - Honeypots for attack detection - Web dashboard for monitoring - Single bash script, no complex installation
The tagline is "not perfect but better than most" because I'm tired of security vendors claiming their tools are flawless. This actually works, costs $0, and you can read every line of code.
I know bash isn't the sexy choice for security tools, but it runs everywhere, has zero dependencies, and most Linux admins can read/modify it. Sometimes boring technology that works is better than fancy technology that doesn't.
It's designed for the intersection of "paranoid about security" and "don't have enterprise budgets" - which describes most of us actually running Linux systems.
GitHub: https://github.com/IHATEGIVINGAUSERNAME/theProtector
Been running it on my own systems for months. Catches the stuff that matters and doesn't flood you with false positives. If you hate expensive security theater as much as I do, might be worth a look.
Open to feedback, especially from folks who know more about this stuff than I do.
Thanks, IHATEGIVINGAUSERNAME (yes, I really do hate giving usernames)