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Re: NSFOCUS SA2001-07 : ActivePerl PerlIS.dll Remote Buffer Overflow Vulnerability
From: Indigo <indig0 () talk21 com>
Date: 27 Nov 2001 05:23:18 -0000
In-Reply-To: <20011123042207.11342.qmail () mail securityfocus com>
Having reinstalled Activestate PERL 220.127.116.119 and IIS
from scratch I agree that the default setings do not
allow you to exploit the overflow. You must
uncheck 'check file exists'. I have not checked any
earlier versions though.
In the instructions for installing the PerlIIS ISAPI
extension it suggests replacing the mappings for
both .pl and .plx with PerlIIS.dll.
If anyone wants to test 'jack.c' with .plx instead of .pl
all they need to do is change the last line of the
From: Jim <raxor () dexlink com>
Has anyone been able to duplicate this bug ?
A *default* install of IIS5 (tested in w2k pro) with
ActivePerl 18.104.22.1689 is *not* vulnerable to this bug.
order to become vulnerable, you must disable
the "Check that file exists" option for PerlIS.dll. (In
order to do this, open up the IIS MMC, right click on
(virtual) directory in your web server,
choose "Properties", click on the "Configuration..."
button, highlight the ".plx" item, click "Edit", and then
uncheck "Check that file exists".)
Am I wrong or does the ISAPI version of ActivePerl
execute .plx files and not .pl as mentioned in the
On my test machine (win2k pro), by default perl.exe
handles .pl and perlIS.dll handles .plx
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