Failed login attempts

Top source IPs of failed SSH logins in last 24h

journalctl -u ssh --since '24h ago' | grep 'Failed password' | awk '{print $(NF-3)}' | sort | uniq -c | sort -rn | head -10
tool
linux133 commands
tags
linuxsecurity

More linux commands

  • Check sudo access
    sudo -l -U <username>

    List sudo rules for a specific user

  • Add user to group
    usermod -aG docker,sudo alice

    Append user to multiple groups without removing existing ones

  • Show /proc memory maps
    cat /proc/<pid>/smaps | awk '/^Size/{sum+=$2} END{print sum/1024" MB"}'

    Total virtual memory size of a process from smaps

  • Anonymous huge pages status
    grep -E 'HugePages|AnonHugePages|Transparent' /proc/meminfo

    Check if THP / hugepages are used and configured

  • Disable Transparent Huge Pages
    echo never > /sys/kernel/mm/transparent_hugepage/enabled

    Disable THP at runtime (fix for Redis, MongoDB latency spikes)

all 133 linux commands