Thomas Delrue via plug on 8 Apr 2021 16:33:52 -0700


[Date Prev] [Date Next] [Thread Prev] [Thread Next] [Date Index] [Thread Index]

Re: [PLUG] that's nice


I'm with Walt on this one.

As for Fred's suggestion: I see where you're going, but Linux isn't
"that much different" either for this type of attack.

As long as I have physical access to the box, and I can boot from any
medium I want, I can run a Live version of my favorite distro and
replace any binary that I want with my favorite malware to ensure it
runs on next boot.
Heck, from that live-cd (let's call it that, because I'm old enough to
remember knoppix), I can edit anything in /etc, /root, or wherever... I
can even create cron-jobs that run the malware-of-my-choice as root
every 5 minutes next time you boot up.

How's that not similar to what you describe doing with windows registry
files?

Be careful shouting "Windows is not secure, and it's all just security
through obscurity". That's a knife that can cut both ways.

But yeah, what Walt said; there's a reason those policies are in place
(typically because some 'other dumb user' did something 'unwise' and now
we gotta protect ourselves against /that/ too). Circumventing those
should be considered a Career Limiting Move and are not advised!
Better to work the system and see if you can get an exemption or
elevated privileges from those who can bestow those. If not, then I'm
sure there's a reason for that too (see 'some other dumb user' reference
before).

On 4/8/21 19:11, Walt Mankowski via plug wrote:
> Changing obscure registry settings to override your organization's
> security and virus-checking settings on company-owned hardware and/or
> while on the company's VPN sounds like what we used to call a
> "career-limiting move". If they find out they may very well decide to
> fire you for ignoring company policy. Do this at your own risk.
> 
> On Thu, Apr 08, 2021 at 06:58:41PM -0400, Fred Stluka via plug wrote:
>> Jeff (and other PLUG folks),
>>
>> Even if your not a member of the Administrators group, you
>> can probably just casually walk around any restrictions and
>> do whatever you want.  Windows has no security, only
>> obscurity, and it's really not even very obscure.
>>
>> I haven't had time to write it up formally as a tip yet, but I've
>> mapped out an entire tip series on my ongoing battle with
>> "Captain Underpants" (as I call the collective groups of folks
>> at Microsoft who make the high level architectural decisions).
>> This is an excerpt I've roughed out that applies to your
>> situation.
>>
>> ---------------------
>>
>> *Windows obscurity over security*
>>
>> To this day, on Windows, there's no real security.  Just
>> obscurity.  So if you know what value to change and where,
>> you can easily break into anything.  Most everything is still
>> stored in the registry, which is still an unprotected binary
>> file with a proprietary format.
>>
>> So everything is supposedly obscure and secret, but nothing
>> is really secure.  And it turns out, it's not that obscure either
>> because it's the same on every Windows PC in the entire world.
>>
>> Imagine you want to do something on a Windows PC, but don't
>> have permission because a Windows "policy" set by a sys admin
>> disallows it.  just go to another PC where you have admin rights,
>> dump the registry file to an ASCII text REG file, set the policy to
>> allow it, then dump the registry again, and diff the 2 REG files.
>> Copy the part that enforces the "policy" (now allowing it).
>> Paste into into a new REG file.  Apply that REG file to the target
>> PC with the REGEDIT or REGEDT32 command.  You're in!
>>
>> If there's a policy that says you can't apply a REG file to change
>> that part of the registry, no worries.  That policy is also stored
>> in the registry.  See where I'm going with this?  Go to the other
>> PC, dump the registry, change that policy to say you ARE
>> allowed to edit the desired part of the registry, re-dump, diff,
>> copy, paste, and apply to the target PC.  Easy-peasy!
>>
>> I used this technique at a large international corp once.  I was
>> a consultant writing a web app for them.  My web app needed
>> to be allowed to do something when run by one of their users.
>> But their was a Windows policy in place that said the users
>> couldn't do it.  So I created a REG file and pushed it to the web
>> site.  Told the users that if they got an error, just click on the
>> REG file.
>>
>> Windows used its "file associations" to automatically run
>> REGEDIT when the REG file was clicked.  It updated the registry
>> and they were now allowed to do what they needed to do.
>>
>> The sys admins didn't like that at all.  So, they added a new
>> policy that said users couldn't make changes to that part of
>> the registry.  So I updated the REG file to first say that, yes,
>> they COULD make such changes, and then to proceed to
>> make the changes.  I even had it change the policy back
>> afterwards so the new policy was still in effect, to prevent
>> the users from accidentally being allowed to make other
>> changes that the sys admins wanted to disallow.  The sys
>> admins never even noticed that I had casually strolled
>> around their best efforts at "security".
>>
>> As with most (all?) Windows "security, it was like putting a lock
>> on the front door and the key under a specific rock in the
>> garden.  But all Windows systems have the same lock, with the
>> same key under the same rock.  So I was easily able to find the
>> rock (diff the 2 dumped reg files), copy the key (copy/paste
>> into new file), open the door (run the REG file) and then put the
>> key back under the rock (also done by running the REG file).
>>
>> Once I automated it like that, any user could break in with a
>> simple click of a REG file, without having to know any of the
>> security details.  And it left the door locked behind them
>> when they were done so no one would know they'd been
>> there.  Doh!
>>
>> ---------------------
>>
>> Once I write up the series of tips, I'll mail it to my "Windows
>> Users" mailing list, my "Computer Security" mailing list, and
>> perhaps a few others.  And of course, post it to the Tips
>> pages that archive mailings to those lists.  Many of you are
>> already on those mailing lists.  The rest of you should feel
>> free to subscribe at:
>> - http://bristle.com/invite
>>
>> Enjoy!
>> --Fred
>> ------------------------------------------------------------------------
>> Fred Stluka -- http://bristle.com -- Glad to be of service!
>> Open Source: Without walls and fences, we need no Windows or Gates.
>> ------------------------------------------------------------------------
>>
>> On 4/5/21 9:26 AM, Thomas Delrue via plug wrote:
>>> Then your only avenue is to actually talk to those who locked you out
>>> and convince them to change how that task is configured... That'll
>>> likely be a bit of an undertaking.
>>> Just like on linux, you need permissions to modify the process you want
>>> to modify.
>>>
>>> There's even a chance that they themselves don't even have the ability
>>> to change the priority of that task because it could be that it is
>>> configured by the AV installer which obviously configures it as "Highest
>>> Priority" because it's the only thing that matters in the world
>>> according to itself.
>>>
>>> You could always ask for local root as well: a no is what you have, a
>>> yes is what you could get.
>>>
>>> On 4/5/21 09:19, jeffv via plug wrote:
>>>> Thanks for the info, but I don't have admin.
>>>> Normally that would piss me off, but I think they did a good job of
>>>> locking things down to keep us safe from ourselves (and maybe even others).
>>>>
>>>> The program eats everything, making opening browser tabs an event.
>>>>
>>>>
>>>> On 4/5/21 8:53 AM, Thomas Delrue wrote:
>>>>> If you're a member of the administrators group, the command you're
>>>>> looking for is
>>>>>      taskkill /im application.exe /f
>>>>>
>>>>> :P
>>>>>
>>>>> Otherwise, if you want to stay 'nice', you can hop into the task
>>>>> manager, right click on the process that eating up all your CPU and
>>>>> select "Change Priority".
>>>>> It will try to scare you out of doing that but just proceed, everything
>>>>> is fine.
>>>>>
>>>>> All of this will only work if you're on an account that has privileges
>>>>> over that process.
>>>>>
>>>>> More systemically, good luck on convincing those folks that that process
>>>>> should be run in a more 'nice way'. Let me know which arguments worked...
>>>>>
>>>>> On 4/5/21 08:45, jeffv via plug wrote:
>>>>>> I'm fuming because w@rk runs virus scans which eat up every last
>>>>>> resource. I'm all for scans, but it runs at 100% cpu for hours. I want
>>>>>> to contact the correct people and discuss it with them...I don't know if
>>>>>> there's a Windows command to do this...
>>>>>>
>>>>>>
>>>>>> "Linux has a nice command, which can reduce the amount of resources a
>>>>>> program is eating."
>>>>>>
>>>>>> What's it called?
>>>>>>
>>>>>> Nice.
>>>>>>
>>>>>> Yes, what is the nice program called.
>>>>>>
>>>>>> It's nice.
>>>>>>
>>>>>> I'm sure it is, but what's it called?
>>>>>>
>>>>>> Nice.
>>>>>>
>>>>>> Look, I understand it's nice to have this program, but what program?
>>>>>>
>>>>>> Nice.
>>>>>>
>>>>>> Ok, you fire up the program to help you. What do you run?
>>>>>>
>>>>>> Nice.
>>>>>>
>>>>>> and so on....
>>>
>>> ___________________________________________________________________________
>>> Philadelphia Linux Users Group         --        http://www.phillylinux.org
>>> Announcements - http://lists.phillylinux.org/mailman/listinfo/plug-announce
>>> General Discussion  --   http://lists.phillylinux.org/mailman/listinfo/plug
>>
>> ___________________________________________________________________________
>> Philadelphia Linux Users Group         --        http://www.phillylinux.org
>> Announcements - http://lists.phillylinux.org/mailman/listinfo/plug-announce
>> General Discussion  --   http://lists.phillylinux.org/mailman/listinfo/plug
>>
>> ___________________________________________________________________________
>> Philadelphia Linux Users Group         --        http://www.phillylinux.org
>> Announcements - http://lists.phillylinux.org/mailman/listinfo/plug-announce
>> General Discussion  --   http://lists.phillylinux.org/mailman/listinfo/plug

Attachment: OpenPGP_signature
Description: OpenPGP digital signature

___________________________________________________________________________
Philadelphia Linux Users Group         --        http://www.phillylinux.org
Announcements - http://lists.phillylinux.org/mailman/listinfo/plug-announce
General Discussion  --   http://lists.phillylinux.org/mailman/listinfo/plug