Re: SSH brute force blocking tool

["J. Oquendo" <sil () infiltrated net>]

gabriel rosenkoetter wrote:
> You are dealing with output you can't trust there. $13 could be
> anything, including "\n`rm -rf /`". Later on, you pass $13,
> unstripped of newlines, backticks, or any number of other special
> character to a shell running as uid 0. That shell will proceed to
> execute whatever we would like it to, where "we" are "the remote
> attacker who doesn't even have an account".
>
>   
No it can't. Even if it was rm -rf someone placed in, did you not notice 
my grep statement? Only print items with a decimal. At no given point 
anywhere on the 13th column whether its Solaris, NetBSD, FreeBSD, would 
there be an option for someone to craft anything...

FreeBSD
-bash2-2.05b$ uname -a
FreeBSD ethos.disgraced.org 5.4-RELEASE-p14 FreeBSD 5.4-RELEASE-p14 #1: 
Thu May 11 01:34:54 CDT 2006     
sil () disgraced org:/usr/obj/usr/src/sys/ETHOS  i386
-bash2-2.05b$ sudo awk '{print $13}' /var/log/auth.log|sort -ru
57354
57340
57335
56253
55125
49211
40334
37188
3508
33875
33635
33454
32798
3137
2895
2638
2408
2301
2114
-

OpenBSD
# uname -a
OpenBSD hades.disgraced.org 4.0 GENERIC#1 i386
# awk '{print $13}' /var/log/authlog|grep "\."|sort -ru
63.243.158.221
61.129.85.230
220.132.113.163
219.149.211.49
213.195.75.41
206.210.96.56

> I don't believe the suggestion was ever that you had malicious
> intent, but rather that you have very horrible coding security
> habits.
>
>   
This should have been stated to the list as opposed to "You're 
backdooring people"

> I'm disinclined to sort out which of your machines I can get root on
> right now because you are running this script, but I would expect
> that someone reading this mailing list is already on the way and
> would strongly advise that you disable those cron jobs.
>   
I'll give you addresses if you'd like to take a shot at it.


--
====================================================
J. Oquendo
http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x1383A743
sil . infiltrated @ net http://www.infiltrated.net 

The happiness of society is the end of government.
John Adams

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