Category Archives: Uncategorized

Here’s how to patch Ubuntu 8.04 or anything where you have to build bash from source

UPDATED: I have updated the post to include the post from gb3 as well as additional patches and some tests

Just a quick post to help those who might be running older/unsupported distributions of linux, mainly Ubuntu 8.04 who need to patch their version of bash due to the recent exploit here:

http://thehackernews.com/2014/09/bash-shell-vulnerability-shellshock.html

I found this post and can confirm it works:

https://news.ycombinator.com/item?id=8364385

Here are the steps(make a backup of /bin/bash just in case):

#assume that your sources are in /src
cd /src
wget http://ftp.gnu.org/gnu/bash/bash-4.3.tar.gz
#download all patches
for i in $(seq -f "%03g" 1 28); do wget http://ftp.gnu.org/gnu/bash/bash-4.3-patches/bash43-$i; done
tar zxvf bash-4.3.tar.gz
cd bash-4.3
#apply all patches
for i in $(seq -f "%03g" 1 28);do patch -p0 < ../bash43-$i; done
#build and install
./configure --prefix=/ && make && make install
cd ../../
rm -r src

To test for exploits CVE-2014-6271, CVE-2014-7169, CVE-2014-7186, and CVE-2014-7187 I have found the following information at this link

To check for the CVE-2014-6271 vulnerability

env x='() { :;}; echo vulnerable' bash -c "echo this is a test"

it should NOT echo back the word vulnerable.


To check for the CVE-2014-7169 vulnerability
(warning: if yours fails it will make or overwrite a file called /tmp/echo that you can delete after, and need to delete before testing again )

cd /tmp; env X='() { (a)=>\' bash -c "echo date"; cat echo

it should say the word date then complain with a message like cat: echo: No such file or directory. If instead it tells you what the current datetime is then your system is vulnerable.


To check for CVE-2014-7186

bash -c 'true < || echo "CVE-2014-7186 vulnerable, redir_stack"

it should NOT echo back the text CVE-2014-7186 vulnerable, redir_stack.


To check for CVE-2014-7187

(for x in {1..200} ; do echo "for x$x in ; do :"; done; for x in {1..200} ; do echo done ; done) | bash || echo "CVE-2014-7187 vulnerable, word_lineno"

it should NOT echo back the text CVE-2014-7187 vulnerable, word_lineno.

Not much to see here

So I thought I might try to update this blog more often. I’m not committing to any schedule or anything, just when I can. I think tonight i’ll just add some bulletpoints and see where it takes me.

– we gained a roommate
– I REALLY need to continue/finish some projects:
— Fender Amp kit for a friend
— iMacquarium
— NES kiosk emulator
— car GPS/camera
— rebuild servers

– We’ve started to clean and organize the house a bit. Still tons of work to do there
– oh, I’m allergic to the outside and a lot of the inside too. Yup, dust, molds, weeds, trees(yes, all of them), cats and dogs. I start the allergy shots in November. Hopefully we don’t have another episode like I did with my tests last week.

– And last but not least, lots of big changes at work. Not sure yet which direction they are going but I’m trying to stay optimistic.

More to come .. Maybe soon