full-disclosure - file_exists() bypassing , critical problem ?

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From: lostnoobs at security-challenge.com (Nourredine Himeur)
Subject: file_exists() bypassing , critical problem ?



> Nourredine Himeur wrote:
>
> >>There are various methods for securing file_exists() ...
> >
> > If you want to secure ... so that's unsecure , is'nt it ?
> >
> >
> >>I don't think that is critical problem.
> >
> > If it's not a problem Why you show us a methode to secure ?
> >
> > I think many programmers don't know this problem exists !
> > But there is too much hypocresy in php community to admit this
> > vulnerability.
> >
> > The article : http://www.zend.com/zend/art/art-oertli.php
> > don't talk about this sorry...
> >
> > Nourredine Himeur
> >
> > www.security-challenge.com
> >
> >
> >
> >
> > _______________________________________________
> > Full-Disclosure - We believe in it.
> > Charter: http://lists.netsys.com/full-disclosure-charter.html
>
> I do not believe this is a security vulnerability. I would rather file
> it under "undefined behaviour"; it's odd, but not an immediate threat.
> One wonders if is_file()/is_dir() aren't more useful in this case.
>
> Having files that will be include()d in your GET/POST request is bad
> programming anyway.
>
>
> Jorrit Kronjee
>


Ok , so we can put the function file_exists() in dustbin...

because everybody says :
" One wonders if is_file()/is_dir() aren't more useful in this case. "
" is bad programming anyway."
" There are various methods for securing file_exists()  "

It's a bug , you can say "This is a script" PHP is a scripting language .

CAN WE USE FILE_EXISTS() WITHOUT SECURE IT ?

I'm sorry but for me it's really a Bug

if file_exists("[anything]/../file.txt") is different as
file_exists(./file.txt)

and include("./[anything]/../file.txt") is same as include("./file.txt")

or file("./[anything]/../file.txt") is same as file("./file.txt")

or fpassthru("./[anything]/../file.txt") is same as fpassthru("./file.txt")

JOKE :
Dialogue between Me,file_exist(),include(),file() and fpassthru()
-----------------------------------------------------

Nourredine Himeur : - Hi file_exists()

file_exists() : - Hi Nourredine Himeur

Nourredine Himeur: - how are you ?

file_exists() : - Fine and you ?

Nourredine Himeur : - Just one question
        - Is the file toto.txt exist ?

file_exists() : - Yes

Nourredine Himeur : - Ok ... but...
        - Is the file ./prout/../toto.txt exist ?

file_exists() : - No

Nourredine Himeur : - but include("./prout/../toto.txt") include the file
toto.txt so it's exists ,isn't it ?

file_exists() : - Sorry but we programming me for reqest No , I'm so stupid
!!!!

include() : - Yes you're so stupid ./lol/../toto.txt exist really
file() : - Same thinks , I see ./foo/../toto.txt too.
fpassthru() : - Same !
-----------------------------------------------------

;-)

Nourredine Himeur

www.security-challenge.com