Linux on fahmi's website

What's inside this .xhtml file

Thu, 21 Oct 2021 00:00:00 +0000

Recently, I got a spam email from Afinei Kosminski. I’m curious what’s inside the .xhtml in the attachment.

So, if I click the attachment, it will change the current tab on my browser to the url that’s base64-encoded.

😲

Notes...

Sun, 26 Sep 2021 00:00:00 +0000

Python 3 http.server

Quickly sharing files via web browser

$ python -m http.server
$ python -m http.server 1234
$ python -m http.server 1234 --bind 127.0.0.1

Knocking Ports, to open SSH session (Port Knocking was setup with iptables)

#!/bin/bash
HOST=$1
shift
for ARG in "$@"
do
nmap -Pn --host_timeout 15 --max-retries 0 -p $ARG $HOST
done

Usage:

$ sh knock.sh 172.16.0.81 8881 7777 9991

Warrior of The Net

https://www.youtube.com/watch?v=PBWhzz_Gn10

Upgrading Linux Kernel on Gentoo

$ ssh -l fahmi 172.16.0.66
$ tmux new -s upgrade
# eselect kernel list
# eselect kernel set 3 (set to the newest kernel, in my case linux-4.1.4-hardened is on the 3rd list)
# cp /boot/config-3.18.9-hardened /usr/src/linux/.config
# cd /usr/src/linux
# make olddefconfig
# uname -a
Linux gentoo 3.18.9-hardened #1 SMP Tue Aug 18 13:01:38 WIB 2015 x86_64 Intel(R) Core(TM)2 Duo CPU T8100 @ 2.10GHz GenuineIntel GNU/Linux
# make -j3
# make modules_install
# make install
# genkernel --install initramfs
# cd /boot
# mkdir ~/oldkernel
# mv config-3.18.9-hardened initramfs-genkernel-x86_64-3.18.9-hardened vmlinuz-3.18.9-hardened kernel-genkernel-x86_64-3.18.9-hardened ~/oldkernel/
# grub2-mkconfig -o /boot/grub/grub.cfg
# reboot

$ ssh -l fahmi 172.16.0.66
$ su -
# cd /usr/src/linux
# rm -r linux-3.18.9-hardened/ linux-4.0.8-hardened/
# rm /boot/System.map-3.18.9-hardened /boot/System.map-genkernel-x86_64-3.18.9-hardened
# rm -r /lib/modules/3.18.9-hardened/

https://wiki.gentoo.org/wiki/Kernel/Removal

Linux From Scratch 7.7 Systemd

Tue, 15 Sep 2015 00:00:00 +0000

Downloading the book (HTML version or PDF)

$ wget http://www.linuxfromscratch.org/lfs/downloads/stable-systemd/LFS-BOOK-7.7-systemd.pdf

Host System
Thinkpad X61, 2GB of RAM, Core2 Duo T8100 2.10GHz
Hardened-Gentoo x86_64
GPT Partition
172.16.0.66
Separate partition /dev/sda4, for LFS

Host Partition:
Device          Start          End              Sectors        Size    Type
/dev/sda1      2048          6143            4096            2M      BIOS boot
/dev/sda2      6144          268287        262144        128M Linux filesystem
/dev/sda3      268288      8656895      8388608      4G       Linux filesystem
/dev/sda4      8656896    29628415    20971520    10G     Linux filesystem
/dev/sda5      29628416 234439599 204811184 97.7G Linux filesystem

Grsecurity + PaX on laptop

Wed, 13 May 2015 00:00:00 +0000

About 2 weeks ago I decided to install linux-grsec on my laptop, followed the archwiki and boot the kernel. These are several things I experienced:

can’t open palemoon
successfully opened gns3, but Cisco IOS won’t boot.
you need to install virtualbox-host-dkms and starting guest OS makes computer hang.
QEMU got no issue so far.

here’s the output of dmesg that i got:
grsec: denied RWX mmap of <anonymous mapping> by /usr/bin/dynamips[dynamips:2864] uid/euid:1000/1000 gid/egid:100/100, parent /usr/bin/gns3server[gns3server:28267] uid/euid:1000/1000 gid/egid:100/100

Configuring TFTP Server on CentOS 6.6 & Archlinux ARM

Fri, 23 Jan 2015 00:00:00 +0000

In this tutorial, I’m using a Raspberry Pi and old dead-battery ThinkPad X61+docking. I installed ArchLinux ARM on Raspberry Pi and Centos 6.6 on X61. They’re gonna be used to remotely back up Cisco’s flash, startup-configuration and perform upgrade if needed. Cisco devices I’m using are Cisco Switch 2950 and Cisco Router 2621xm.

X61’s IP address = 172.16.0.66/26

Raspberry PI’s IP address = 172.16.0.67/26

Raspberry PI configuration

Install tftp-hpa

[veroke@T430 ~]$ ssh fahmi@172.16.0.67
fahmi@172.16.0.67's password:
[fahmi@alarmpi ~]$ sudo pacman -S tftp-hpa

tftpd.service

Refer to Archwiki https://wiki.archlinux.org/index.php/Tftpd_server, we should create a copy of the tftpd.service and modify ExecStart with the appropriate directory to use as the tftp root.

snort, psad, fwsnort, and fwknop on Arch Linux ARM (Raspberry Pi)

Fri, 23 Jan 2015 00:00:00 +0000

ssh to your raspberry pi server

ssh fahmi@172.16.0.27

screen session

make new screen session, named snort. compiling snort, fwknop, and fwknop using Raspberry Pi is gonna take long. So, you can just leave it over night and reattach to screen session in the morning with “screen -r”. Another advantage of using screen is when you lost connection to the server, you can just reattach to the session and continue working from where you left off. Or you can just use tmux as an alternative to screen.