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Find brute force attempts on SSHd

Terminal - Find brute force attempts on SSHd
cat /var/log/secure | grep sshd | grep Failed | sed 's/invalid//' | sed 's/user//' | awk '{print $11}' | sort | uniq -c | sort -n
2009-03-30 15:48:24
User: empulse
Functions: awk cat grep sed sort sshd uniq
6
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Find brute force attempts on SSHd

Searches the /var/log/secure log file for Failed and/or invalid user log in attempts.

Show sample output | Add to favourites | Report as malicious

Know a better way?

If you can do better, submit your command here.

What others think

On Ubuntu, it's /var/log/auth.log

Comment by goodevilgenius 74 weeks and 2 days ago

cat overload! :-)

< /var.log/secure grep sshd | grep Failed | sed 's/invalid//' | sed 's/user//' | awk '{print $11}' | sort | uniq -c | sort -n

Comment by mpb 74 weeks and 2 days ago

I was wondering why have the sed commands? Wouldn't just making awk '{print $13}' make more sense? I'm a bash newbie and would love the explanation.

Comment by frailotis 74 weeks and 2 days ago

After messing around, here's what I've got and I think it's a bit cleaner. Let me know if that's true or not.

awk '/sshd/&& /Failed/ {print $13}' /var/log/secure | uniq -c | sort -nr

Comment by frailotis 74 weeks and 2 days ago

@frailotis you need to sort first before piping to uniq, Also, you're missing some IP addreses and getting random data by not searching and replacing for "invalid user". However, yes, people need to learn awk rather that pipe cat to grep to grep to sed to sed then to awk, with sort used twice!

awk '/sshd/ && /Failed/ {sub(/invalid user/,""); print $11}' /var/log/auth.log | sort -n | uniq
Comment by atoponce 74 weeks and 2 days ago

BTW- /var/log/secure on Fedora-based systems, /var/log/auth.log in Debian-based systems.

Comment by atoponce 74 weeks and 2 days ago

You can make the original command a little cleaner by combining sed expressions like this:

cat /var/log/messages | grep sshd | grep Failed | sed -e 's/invalid// ; s/user//' | awk '{print $11}' | sort | uniq -c | sort -n
Comment by unixmonkey6951 42 weeks and 1 day ago

Your point of view

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