http://www.webhostingtalk.com/showthread.php?p=8130717#post8130717

AHAHAHAHAH

EDIT: per una spiegazione più completa:
http://blog.grg-web.eu/2012/05/rfc-ignorate-la-fine-del-mondo-inizia-con-fastweb/

What is chargen?

From wikipedia:
<<In the UDP implementation of the protocol, the server sends a UDP datagram containing a random number (between 0 and 512) of characters every time it receives a datagram from the connecting host.>>

Apparently there’s absolutely no handshake at all with chargen… only the TCP version (obviously) requires handshake…

How are hosts running chargen (UDP) used as botnets?

To execute the attack people are sending spoofed UDP packets with a forged source IP address to hundreds of hosts running chargen (and there are many of them!).
These hosts just reply to the apparent source of such packet as they are intendend to do… the problem is that they are replying to the forged IP address… that host has never requested something to them!

Is my machine vulnerable?

To test if your machine could be exploited just run:
echo t | nc -u X.X.X.X 19

replace X.X.X.X with an IP running chargen… If you got a reply you just found a host that can be used as part of a ddos botnet…

How can I make my machine secure?

details on how to disable chargen service:
http://shalb.com/kb/entry/10043/
(on that link they refer to another weak point of chargen: looks like it can also be used to let machines running chargen attack each-other…)

if you are running chargen on one of your hosts: CLOSE THAT FUCKING PORT (IN UDP 19)!
if you are a carrier/ISP that allows spoofed traffic to leave your network: HOPE YOU GET BANKRUPT AND CLOSE YOUR FUCKING DOORS FOR GOOD!

ktnxbye

in order to add it back again this is the calendar address:

it.italian#holiday@group.v.calendar.google.com

just add it as it was a new calendar you want to link

another special calendar you might want to add is:

#contacts@group.v.calendar.google.com

ls -al /etc/munin/plugins/

easy fix:

munin-node-configure --suggest --shell | sh ; service munin-node restart

to verify what was detected just run:

ls -al /etc/munin/plugins/

yum install ntp
ntpdate -s it.pool.ntp.org
hwclock -w

on a side not to change the timezone on RHEL 6.x adjust the clock settings config file:

nano -w /etc/sysconfig/clock

set it as you wish:

ZONE="Europe/Rome"

then set the localtime

cp /usr/share/zoneinfo/Europe/Rome /etc/localtime

currently it does support certain daemons out of the box… but vspftd is not one of those
This a *very basic* (it does not pass the offending username to bfd) script to add VSFTPD support to BFD.

You just need to create a file named “vsftpd” into the BFD ./rules/ directory and paste this content into it:

REQ="/usr/sbin/vsftpd"
 
if [ -f "$REQ" ]; then
 LP="/var/log/vsftpd.log"
 TLOG_TF="vsftpd"
 
 #Mon Mar 28 23:57:38 2011 [pid 9897] [asdasd] FAIL LOGIN: Client "127.0.0.1"
 
 ## VSFTPD
 ARG_VAL=`$TLOG_PATH $LP $TLOG_TF | grep -w 'FAIL LOGIN' | sed -r 's/^.{0,}Client .//' | sed 's/"/:vsftpd/g'`
fi

This script refers to the standard vsftpd rhel/centos installation…
If the logfile is placed elsewhere (vsftpd_log_file) or if the option “syslog_enable” in vsftpd.conf has been enabled it needs to be adjusted

PS: this was a NON-WORKING test (usernames with a space in it where making it fail):

ARG_VAL=`$TLOG_PATH $LP $TLOG_TF | grep -w 'FAIL LOGIN' | awk '{print $12":"$8}' | tr '[]"'`

but you can still get it working…

Why do I care about this very old printer?: I really like this printer, I would never exchange it with another one.
I printed a shitload of paper using this piece of plastic… never had a problem… and not only that: printing with this printer is so fucking cheap!
(This printer support black & white printing using ONLY the black cartridge… it even works without the color cartridge in place! )

Windows Vista fully supported it and the vista drivers works perfectly on windows 7 too…

This trick works with many other peripherals that were supported by Vista but dropped on Seven…

What you’ll need:

• Windows vista dvd ISO (I used it_windows_vista_x64_dvd_X12-61200.iso)
• 7-zip ( http://www.7-zip.org/ )
• 1gb disk space

Ho to do it:

• open the ISO with 7-zip
• browse into the directory \sources\
• double click on the file install.wim
• browse into the \1\Windows\System32\ directory
• extract drivers and DriverStore directories somewhere
• connect the printer, when windows asks about drivers: point it to the directory where you have previously extracted the vista drivers
• done ^^

At this point you will have your PSC 2110 working on windows 7 (both printing and scanning are perfectly working)

If you cannot find the drivers into the cd this is the windows 7 64bit pack:
http://www.evcz.tk/archivio.files/psc.2110/hp.psc2110.drivers.win7.x64.7z

PS: for even more cheap printing check out Cartucce HP PSC 2110

phpipblocker (last version 0.99j)
phpipblocker archive

php2dns (last version 0.91beta)
php2dns archive

nothing more, nothing less…

Valid alternatives: http://free-av.com/

I get in touch with many people related to centos reinstall… I’m aware in certain conditions it’s a pain to have it rolling properly…
I do this for work, just contact me if you want it done for a small fee

There are some ISPs in the dedicated servers market that are offering crappy CentOS installs…

With “crappy” I mean: broken/modifed images…

The worst example I had the opportunity to try was OVH.
OVH is in general a very good dedicated hosting provider offering very nice services at an impressive low price… but they have the bad attitude to install custom operating systems that many times cannot be reverted back to the original kernels

One of them is their CentOS 5 install… Lucky for us it’s not a big problem as, most times, it’s possible to do a clean CentOS install

This is a simple procedure to do an official, clean install from the genuine CentOS disks

1. Install CentOS from the OVH manager with the default partitioning proposed by OVH
   (this procedure will work with whatever operating system you want… i suggested centos so it will report “centos” also in the ovh manger make sure you are able to get grub working on the os you want to use )
2. once everything is done log into the box via ssh as root
3. issue these commands:

   yum update -y
   mkdir /centos_install
   cd /centos_install
   wget http://it.centos.contactlab.it/6/os/x86_64/images/pxeboot/initrd.img
   wget http://it.centos.contactlab.it/6/os/x86_64/images/pxeboot/vmlinuz
   cp vmlinuz /boot/vmlinuz.cent.pxe
   cp initrd.img /boot/initrd.img.cent.pxe

4. Add to/Edit the grub menu.lst entry to load the pxe kernel (note: if you were already using grub you do not need to type again the first 2 lines )

   nano -w /boot/grub/menu.lst

   in that file paste:

   title Centos Install (PXE)
   root (hd0,0)
   kernel /boot/vmlinuz.cent.pxe vnc vncpassword=YOURPSW headless ip=YOURIP netmask=255.255.255.0 gateway=GATEWAYIP dns=8.8.8.8 ksdevice=eth0 method=http://it.centos.contactlab.it/6/os/x86_64/ lang=en_US keymap=us
   initrd /boot/initrd.img.cent.pxe

replace

• YOURPSW with the VNC password you want setup (at least 6 chars long on centos5!)
• YOURIP with the ip of the box…
• GATEWAYIP with the gateway assigned to your boxHint: you can see the gateway ip by issuing

  route -n | grep UG

once you have done this you need to count the number of times “title” appears in the file, press ctrl +x, and save the file

• type:

  grub

  write in there:

  savedefault --default=2 --once

  replace 2 with the number of times “title” appeared in manu.lst minus one (if you counted 6 “title” entries… write 5 in here)

• reboot

After issuing the reboot ping the box (should take max 2minutes to take up the network)… 30seconds (or more… depending how fast your box is) after it starts replying to the ping open a vnc client (on windows i suggest ultravnc) and connect to

YOURIP:1

put as password the one you placed as YOURPSW …

install CentOS

Tested on:

Success

• OVH kimsufi reloaded (Intel Celeron 220)
• OVH kimsufi reloaded xl (Intel e2180, Asus P5VD2-VM)
• OVH kimsufi reloaded xxl (Intel e7200, Intel DG31PR)
• OVH SP BestOF (Intel e6750)
• Keyweb KM 4400 DC (Intel e4500, Ati chipset IIRC)
• Intel i5 / p55 / e1000e eth
• OVH kimsufi Q-1T
• OVH kimsufi i7-2T (pxe kernel modification required: instructions, needs the eth attansic module)
• Dell R200
• Dell R410
• a lot others….

Known problems

• If you didn’t follow exactly the how-to and did a custom partioning with /boot/ partition on it’s own you will have to take away the /boot/ path from the menu.lst …
• OVH netboot kernels might no more be able to boot into your box (even without LVM… dunno… maybe I did a too “base” install…)
• keep a vnc password short… most clients cannot auth with long passwords
• some ISPs may block incoming vnc traffic in that case consider to use the vncconnect=host:port (instead of vnc) trigger to have the server connecting to your PC (documentation: vncconnect )
• I had big trouble with certain servers not being able to run the CentOS 5.5 pxe install… on those I had to fall-back using the 5.4 install.. in case you want to use them you can find everything in here: http://vault.centos.org/5.4/: make sure to adjust also the mirror in the grub config file!

If not working

• On certain images reference grub config file is /boot/grub/grub.cfg instead of menu.lst
• If the box do not come up (ping) after the reboot… do a reimage and try over… double check the settings… expecially network settings.
• If the box does not works (not ping reply) and you are sure networking is set correctly try to boot vkvm to see if the PXE kernel is loaded properly to exclude any problem with the bootloader.

Random things

• http://dcantrel.fedorapeople.org/doc/vnc/VNC_Whitepaper-vnc-modes-in-anaconda.html
• http://fedoraproject.org/wiki/Anaconda/Options
• in this example I used the 32bit image… 64bit is exactly the same, just change the image you fetch at the beginning from the CentOS mirror and the mirror path into the grub config
• if you are running grub2 (like ubuntu 9.10) this is an example on how to set it up:

  sudo chmod +x /etc/grub.d/40_custom
  sudo nano /etc/grub.d/40_custom

  place in there something like:

  menuentry "centos.pxe" {
  set root=(md0)
  kernel /boot/vmlinuz.cent.pxe vnc vncpassword=YOURPSW headless ip=YOURIP netmask=255.255.255.0 gateway=GATEWAYIP dns=8.8.8.8 ksdevice=eth0 method=http://ftp.hosteurope.de/mirror/centos.org/5/os/i386/ lang=en_US keymap=us
  initrd /boot/initrd.img.cent.pxe
  }

  save and issue:

  sudo update-grub2