Hmm even that is no good.
I would also suggest chown root.root ${TMP_FILE} in there too after chmod. In
case a user
is attempting to insert a change during the tiny window in which the file is
about to be clobbered.
Sorry for wasting bandwidth but for the sake of correctness, I think it's the
right thing to do.
Cheers, Mike.
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Michael L
Benjamin
Sent: Friday, September 02, 2005 04:31 PM
To: [email protected]
Subject: RE: [Full-disclosure] SSH Bruteforce blocking script
Ok, well spotted. Something for me to fix there.
Here you go, add these lines to the script just after the touch:
chmod 700 ${TMP_FILE}
> ${TMP_FILE}
My apologies, that is a no-no and something I should have spotted.
I originally thought about doing this with arrays in memory. I might go back to
that later.
Thanks for your input.
Cheers, Mike.
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Alejandro Barrera
Sent: Friday, September 02, 2005 04:04 PM
To: [email protected]
Subject: Re: [Full-disclosure] SSH Bruteforce blocking script
Well, we apreciate your script although I would preffer to stay with my nice
bruteforcing attempts than to create an insecure temporary file bug:
[EMAIL PROTECTED]:~$ cat test.sh
#!/bin/sh
SCRIPT_NAME=$(basename $0)
TMP_FILE="/tmp/${SCRIPT_NAME}.$$"
touch ${TMP_FILE}
echo "pwn3d" > ${TMP_FILE}
exit
[EMAIL PROTECTED]:~$ cat data
pr0n g0ld collection: ....
[EMAIL PROTECTED]:~$ ln -s /home/ergosum/data /tmp/test.sh.18359 [EMAIL
PROTECTED]:~$ ln -s /home/ergosum/data /tmp/test.sh.18361 [EMAIL PROTECTED]:~$
ln -s /home/ergosum/data /tmp/test.sh.18362 [EMAIL PROTECTED]:~$ ./test.sh
[EMAIL PROTECTED]:~$ cat data pwn3d
> #!/bin/ksh
> #
> # ssh_brute_blocker
> #
> # 05/07/2004 15:05 - Michael L. Benjamin #
> SCRIPT_NAME=$(basename $0)
> LOG_FILE="/var/log/secure"
> DENY_FILE="/etc/hosts.deny"
> TMP_FILE="/tmp/${SCRIPT_NAME}.$$"
> INBOUND_IP=""
> INLINE=""
> GUESS_COUNT=0
> PERMIT_GUESS=4
> touch ${TMP_FILE}
> while :
> do
> tail -10000 ${LOG_FILE} | grep "Failed password for illegal user" |
> awk -F"from" {'print $2'} | awk {'print $1'} | uniq > ${TMP_FILE}
--
Alejandro Barrera García-Orea
R&D Engineer
c/ Alcala 268 28027 Madrid
Office: +34 91 326 66 11
Fax: +34 91 326 66 11
e-mail: [EMAIL PROTECTED]
_______________________________________________
Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
Hosted and sponsored by Secunia - http://secunia.com/
_______________________________________________
Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
Hosted and sponsored by Secunia - http://secunia.com/
_______________________________________________
Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
Hosted and sponsored by Secunia - http://secunia.com/
