4:42 a.m.
hi list, whilst trying to run this bash command
for w in {A..Z}{A..Z}{A..Z}{A..Z}{A..Z}{A..Z}{A..Z}{A..Z} ;do echo
$w;done > wl1
on my aspire one (which is running rawhide) it kept crashing my system
down with no reasons shown in any of the logs, so i tried it on my
desktop machine which is an athlonx2 6000 with 2GB of ram and a raid0
array, with 2GB of swap and it too crashed the terminal but it did give
me an error and it turned out to be an oom error so i tried upping the
swap partition to 10GB and i'm still getting an oom crash, can anyone
suggest a way of getting the command to dump the output to disk each
time it gets close to running out of memory? or is this command always
doomed to fail?
tia
phil
3:34 p.m.
On Sun, 2009-10-04 at 13:21 -0700, jack craig wrote:
you might consider piping your echo $w | xargs...
[Please don't top-post. See the Guidelines].
How would that help? The problem isn't that an argument stack is
overflowing but that the Shell itself is running out of memory.
poc
5:09 p.m.
On Tue, 2009-10-06 at 19:17 +0100, psmith wrote:
i'm doing some pen testing of my brother's companies network
he wants
me
to see if it's possible to get in so I'd be using the output as a
word
list, and yes unfortunately i'll need all of it for comparison i'm
not
sure if the program (aircrack) takes data from a pipe as a word list,
but i'll look into it
If by "getting in" you mean "guessing a password" and if the password
system accepts only 8 upper-case letters, then the answer is "it depends
how long the system takes to accept or reject an attempt". There are
26^8 possible combinations i.e. 208,827,064,576 and on average you need
to check half of them, assuming they are really random. If each attempt
takes 1 second, you get on average 6621 years for a hit on a specific
password. OTOH if an attempt takes 1 microsecond, it's just under 60
hours.
Things to bear in mind:
* If these are user-generated passwords, they are not random.
* If the intruder can check against multiple users at once (i.e. he
doesn't care which one it is) the numbers drop dramatically.
* If the system is at all well-designed it will block attempts after
some number of failures from the same origin, e.g. 3. In any case, it
should report bursts of failed attempts to the administrator.
* Social engineering beats brute force a large percentage of the time.
IOW, and in the absence of more concrete information, I'd say you're not
learning anything special by doing a brute-force check like this.
poc
2:20 p.m.
Mikkel wrote:
psmith wrote:
> for a in {A..Z}; \
> do for b in {A..Z}; \
> do for c in {A..Z}; \
> do for d in {A..Z}; \
> do for e in {A..Z}; \
> do for f in {A..Z}; \
> do for g in {A..Z}; \
> do for h in {A..Z}; \
> do echo $a$b$c$d$e$f$g$h; \
> done;done;done;done;done;done;done;done; > wl1
>
> now i've just got to wait for the new hard drives to arrive and also
> work out how to get it to start outputting a different file every 2GB or
> so :-)
>
> thanks again
> phil
>
Well, if you are willing to setting for a specific count, instead of
size, you could change the last line to:
done;done;done;done;done;done;done;done; > wl1.$a$b$c$d
or
done;done;done;done;done;done;done;done; > $a$b$c$d.w11
Mikkel
Oops - I was not thinking - change the last line to:
done;done;done;done;done;done;done;done;
and change the echo line to:
do echo $a$b$c$d$e$f$g$h; >> $a$b$c$d.w11 \
Mikkel
--
Do not meddle in the affairs of dragons,
for thou art crunchy and taste good with Ketchup!
2:03 p.m.
Around 07:17pm on Tuesday, October 06, 2009 (UK time), psmith scrawled:
i'm doing some pen testing of my brother's companies network
he wants me
to see if it's possible to get in so I'd be using the output as a word
list, and yes unfortunately i'll need all of it for comparison i'm not
sure if the program (aircrack) takes data from a pipe as a word list,
but i'll look into it
Have you considered how long it will take to try 208 billion attempts at
cracking the system! Or have I misunderstood what you are doing?
--
(o< www.stevesearle.com
//\ Powered by Fedora
V_/_ No MS products were used in the creation of this message
20:01:27 up 20 days, 9:02, 1 user, load average: 0.11, 0.03, 0.02
1:41 p.m.
psmith wrote:
for a in {A..Z}; \
do for b in {A..Z}; \
do for c in {A..Z}; \
do for d in {A..Z}; \
do for e in {A..Z}; \
do for f in {A..Z}; \
do for g in {A..Z}; \
do for h in {A..Z}; \
do echo $a$b$c$d$e$f$g$h; \
done;done;done;done;done;done;done;done; > wl1
now i've just got to wait for the new hard drives to arrive and also
work out how to get it to start outputting a different file every 2GB or
so :-)
thanks again
phil
Well, if you are willing to setting for a specific count, instead of
size, you could change the last line to:
done;done;done;done;done;done;done;done; > wl1.$a$b$c$d
or
done;done;done;done;done;done;done;done; > $a$b$c$d.w11
Mikkel
--
Do not meddle in the affairs of dragons,
for thou art crunchy and taste good with Ketchup!
1:24 p.m.
On 04/10/09 15:28, Mikkel wrote:
Patrick O'Callaghan wrote:
> On Sun, 2009-10-04 at 13:54 +0100, psmith wrote:
>
>> do you have any suggestions what/where i should be looking to get my
>> required output?
>>
> As Sam says, your initial attempt is trying to produce all 1.5TB at
> once, which is why it blows up, but that's going to happen anyway even
> if you program the same thing in C. IOW it's not an issue with the Shell
> per se, but with the approach to the problem.
>
> Assuming you actually want all 1.5TB of data (really?) you'd be better
> consuming it as it's produced, perhaps via a pipe. Of course that
> depends on what you're doing with it, which you haven't said.
>
> poc
>
>
One way to do it would be to break it down into nested loops. I am
not sure you could do it in bash - I am not sure how bash handles
loops. You can try something like: (Not tested)
for a in {A..Z}; \
do for b in {A..Z}; \
do for c in {A..Z}; \
do for d in {A..Z}; \
do for e in {A..Z}; \
do for f in {A..Z}; \
echo $a$b$c$d$e$f ; \
done ; done ; done ; done ; done ; done ; done ; done
Mikkel
thanks mikkel :-) this got it to output the data to the file as it was
working though the command needed to be
for a in {A..Z}; \
do for b in {A..Z}; \
do for c in {A..Z}; \
do for d in {A..Z}; \
do for e in {A..Z}; \
do for f in {A..Z}; \
do for g in {A..Z}; \
do for h in {A..Z}; \
do echo $a$b$c$d$e$f$g$h; \
done;done;done;done;done;done;done;done; > wl1
now i've just got to wait for the new hard drives to arrive and also
work out how to get it to start outputting a different file every 2GB or
so :-)
thanks again
phil
1:17 p.m.
On 04/10/09 14:03, Patrick O'Callaghan wrote:
On Sun, 2009-10-04 at 13:54 +0100, psmith wrote:
> On 04/10/09 11:17, Sharpe, Sam J wrote:
>
>> 2009/10/4 psmith<psmith(a)fedoraproject.org>:
>>
>>
>>> hi list, whilst trying to run this bash command
>>>
>>> for w in {A..Z}{A..Z}{A..Z}{A..Z}{A..Z}{A..Z}{A..Z}{A..Z} ;do echo
$w;done>
>>> wl1
>>>
>>>
>> Consider that for a second...
>>
>> You are trying to generate a list of all possible combinations of an 8
>> character word composed of only uppercase letters - that's 26^8
>> combinations (208 Billion). Each word is 8 bytes long, which I make to
>> be 1670616516608 bytes... or to put it another way, 1.5 TB
>>
>> So, you've got 4 GB of virtual memory and you are trying to fit an
>> 1555GB array into it. Simple mathematics says no. Dumping the
>> arguments before it dies is pointless, because it hasn't even got as
>> far as expanding arguments yet.
>>
>> You need to think of another was to do this and I humbly suggest that
>> Bash should not be high on your list.
>>
>>
>>
> thanks for the reality check sam :o
>
> do you have any suggestions what/where i should be looking to get my
> required output?
>
As Sam says, your initial attempt is trying to produce all 1.5TB at
once, which is why it blows up, but that's going to happen anyway even
if you program the same thing in C. IOW it's not an issue with the Shell
per se, but with the approach to the problem.
Assuming you actually want all 1.5TB of data (really?) you'd be better
consuming it as it's produced, perhaps via a pipe. Of course that
depends on what you're doing with it, which you haven't said.
poc
i'm doing some pen testing of my brother's companies network he wants
me
to see if it's possible to get in so I'd be using the output as a word
list, and yes unfortunately i'll need all of it for comparison i'm not
sure if the program (aircrack) takes data from a pipe as a word list,
but i'll look into it
phil
phil
10:58 p.m.
On 09-10-04 06:17:20, Sharpe, Sam J wrote:
2009/10/4 psmith <psmith(a)fedoraproject.org>:
> hi list, whilst trying to run this bash command
>
> for w in {A..Z}{A..Z}{A..Z}{A..Z}{A..Z}{A..Z}{A..Z}{A..Z} ;do echo
$w;done >
> wl1
Consider that for a second...
You are trying to generate a list of all possible combinations of an
8 character word composed of only uppercase letters - that's 26^8
combinations (208 Billion). Each word is 8 bytes long, which I make
to be 1670616516608 bytes... or to put it another way, 1.5 TB
So, you've got 4 GB of virtual memory and you are trying to fit an
1555GB array into it. Simple mathematics says no. Dumping the
arguments before it dies is pointless, because it hasn't even got as
far as expanding arguments yet.
You need to think of another was to do this and I humbly suggest that
Bash should not be high on your list.
Bash should be OK if Pathname Expansion is used instead of the more
general Brace Expansion:
$ for w in [[:upper:]][[:upper:]][[:upper:]][[:upper:]][[:upper:]]
[[:upper:]][[:upper:]][[:upper:]] ; do echo $w ; done
However, if there are no matches, the match string will be tried unless
the shell options failglob is unset and nullglob is set:
$ ( shopt -s nullglob ; shopt -u failglob ; for w in [[:upper:]]
[[:upper:]][[:upper:]][[:upper:]][[:upper:]][[:upper:]][[:upper:]]
[[:upper:]] ; do echo $w ; done )
(Sorry for the wrapping.)
--
____________________________________________________________________
TonyN.:' <mailto:tonynelson@georgeanelson.com>
' <http://www.georgeanelson.com/>
3:47 p.m.
jack craig wrote:
you might consider piping your echo $w | xargs...
When writing to a file, or just printing to the terminal, piping to
xargs does not help anything.
Mikkel
--
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting a bad thing?
3:21 p.m.
you might consider piping your echo $w | xargs...
On 10/04/2009 02:42 AM, psmith wrote:
hi list, whilst trying to run this bash command
for w in {A..Z}{A..Z}{A..Z}{A..Z}{A..Z}{A..Z}{A..Z}{A..Z} ;do echo
$w;done > wl1
on my aspire one (which is running rawhide) it kept crashing my system
down with no reasons shown in any of the logs, so i tried it on my
desktop machine which is an athlonx2 6000 with 2GB of ram and a raid0
array, with 2GB of swap and it too crashed the terminal but it did
give me an error and it turned out to be an oom error so i tried
upping the swap partition to 10GB and i'm still getting an oom crash,
can anyone suggest a way of getting the command to dump the output to
disk each time it gets close to running out of memory? or is this
command always doomed to fail?
tia
phil
--
jack craig
jackc(a)LinuxLightHouse.com
831-684-1375 (Office)
831-596-6924 (cell)
IM: jackcraigaptos (AIM)
_________________________________
This email has been ClamScanned !
www.LinuxLightHouse.com
9:28 a.m.
Patrick O'Callaghan wrote:
On Sun, 2009-10-04 at 13:54 +0100, psmith wrote:
> do you have any suggestions what/where i should be looking to get my
> required output?
As Sam says, your initial attempt is trying to produce all 1.5TB at
once, which is why it blows up, but that's going to happen anyway even
if you program the same thing in C. IOW it's not an issue with the Shell
per se, but with the approach to the problem.
Assuming you actually want all 1.5TB of data (really?) you'd be better
consuming it as it's produced, perhaps via a pipe. Of course that
depends on what you're doing with it, which you haven't said.
poc
One way to do it would be to break it down into nested loops. I am
not sure you could do it in bash - I am not sure how bash handles
loops. You can try something like: (Not tested)
for a in {A..Z}; \
do for b in {A..Z}; \
do for c in {A..Z}; \
do for d in {A..Z}; \
do for e in {A..Z}; \
do for f in {A..Z}; \
echo $a$b$c$d$e$f ; \
done ; done ; done ; done ; done ; done ; done ; done
Mikkel
--
Do not meddle in the affairs of dragons,
for thou art crunchy and taste good with Ketchup!
8:03 a.m.
On Sun, 2009-10-04 at 13:54 +0100, psmith wrote:
On 04/10/09 11:17, Sharpe, Sam J wrote:
> 2009/10/4 psmith<psmith(a)fedoraproject.org>:
>
>> hi list, whilst trying to run this bash command
>>
>> for w in {A..Z}{A..Z}{A..Z}{A..Z}{A..Z}{A..Z}{A..Z}{A..Z} ;do echo $w;done>
>> wl1
>>
> Consider that for a second...
>
> You are trying to generate a list of all possible combinations of an 8
> character word composed of only uppercase letters - that's 26^8
> combinations (208 Billion). Each word is 8 bytes long, which I make to
> be 1670616516608 bytes... or to put it another way, 1.5 TB
>
> So, you've got 4 GB of virtual memory and you are trying to fit an
> 1555GB array into it. Simple mathematics says no. Dumping the
> arguments before it dies is pointless, because it hasn't even got as
> far as expanding arguments yet.
>
> You need to think of another was to do this and I humbly suggest that
> Bash should not be high on your list.
>
>
thanks for the reality check sam :o
do you have any suggestions what/where i should be looking to get my
required output?
As Sam says, your initial attempt is trying to produce all 1.5TB at
once, which is why it blows up, but that's going to happen anyway even
if you program the same thing in C. IOW it's not an issue with the Shell
per se, but with the approach to the problem.
Assuming you actually want all 1.5TB of data (really?) you'd be better
consuming it as it's produced, perhaps via a pipe. Of course that
depends on what you're doing with it, which you haven't said.
poc
7:54 a.m.
On 04/10/09 11:17, Sharpe, Sam J wrote:
2009/10/4 psmith<psmith(a)fedoraproject.org>:
> hi list, whilst trying to run this bash command
>
> for w in {A..Z}{A..Z}{A..Z}{A..Z}{A..Z}{A..Z}{A..Z}{A..Z} ;do echo $w;done>
> wl1
>
Consider that for a second...
You are trying to generate a list of all possible combinations of an 8
character word composed of only uppercase letters - that's 26^8
combinations (208 Billion). Each word is 8 bytes long, which I make to
be 1670616516608 bytes... or to put it another way, 1.5 TB
So, you've got 4 GB of virtual memory and you are trying to fit an
1555GB array into it. Simple mathematics says no. Dumping the
arguments before it dies is pointless, because it hasn't even got as
far as expanding arguments yet.
You need to think of another was to do this and I humbly suggest that
Bash should not be high on your list.
thanks for the reality check sam :o
do you have any suggestions what/where i should be looking to get my
required output?
phil
5:17 a.m.
2009/10/4 psmith <psmith(a)fedoraproject.org>:
hi list, whilst trying to run this bash command
for w in {A..Z}{A..Z}{A..Z}{A..Z}{A..Z}{A..Z}{A..Z}{A..Z} ;do echo $w;done >
wl1
Consider that for a second...
You are trying to generate a list of all possible combinations of an 8
character word composed of only uppercase letters - that's 26^8
combinations (208 Billion). Each word is 8 bytes long, which I make to
be 1670616516608 bytes... or to put it another way, 1.5 TB
So, you've got 4 GB of virtual memory and you are trying to fit an
1555GB array into it. Simple mathematics says no. Dumping the
arguments before it dies is pointless, because it hasn't even got as
far as expanding arguments yet.
You need to think of another was to do this and I humbly suggest that
Bash should not be high on your list.
--
Sam
5377
days inactive
5379
days old
14 comments
7 participants
participants (7)
-
jack craig -
Mikkel -
Patrick O'Callaghan -
psmith -
Sam Sharpe -
Steve Searle -
Tony Nelson