The following security advisory is sent to the securiteam mailing list, and can
be found at the SecuriTeam web site: http://www.securiteam.com
- - promotion
The SecuriTeam alerts list - Free, Accurate, Independent.
Get your security news from a reliable source.
http://www.securiteam.com/mailinglist.html
- - - - - - - - -
Ethereal srvloc Buffer Overflow
------------------------------------------------------------------------
SUMMARY
<http://www.ethereal.com/> Ethereal is "a full featured open source
network protocol analyzer".
Remote exploitation of a buffer overflow vulnerability in the Service
Location Protocol (srvloc) dissectors within Ethereal allows attackers to
crash the vulnerable process or execute arbitrary code.
DETAILS
Vulnerable Systems:
* Ethereal version 0.10.12 and earlier
Immune Systems:
* Ethereal version 0.10.13 (download
<http://www.ethereal.com/download.html> here)
Vulnerable code:
--------------------------------- Begin Code
---------------------------------
/epan/dissectors/packet-srvloc.c:429
static guint8*
unicode_to_bytes(tvbuff_t *tvb, int offset, int length, gboolean
endianness)
{
const char *ascii_text = tvb_get_ptr(tvb, offset, length);
int i, j=0;
guint8 c_char, c_char1;
static guint8 byte_array[255];
if (endianness) {
...
}
}
else
{
for (i = 0; i < length; i++) {
c_char = ascii_text[i];
if (c_char != 0) {
byte_array[j] = c_char;
j++;
}
}
}
byte_array[j]=0;
return byte_array;
}
---------------------------------- End Code
----------------------------------
This function is called with a user-controlled length value on line 581 in
the same file. This allows an attacker to cause an overflow of the
byte_array array, as values greater than 255 may be specified. In lab
analysis, it has been demonstrated that there are several interesting
values beyond this array that make arbitrary code execution possible.
To cause Ethereal to dissect an arbitrary packet with the srvloc
dissector, the source or destination port must be set to TCP port 427, and
the destination port must not be a port with any registered dissector. As
Ethereal does not keep state, a single spoofed TCP data packet can be used
to exploit this vulnerability, regardless of whether there are any ports
listening on either end.
Exploitation could result in remote root access, as Ethereal must have
root privileges to open a raw socket.Ethereal is often used by network
administrators to debug network problems and compromise of a network
administrators machine can lead to further compromise of the network.
Workaround:
When using Ethereal, use the following filter to disable port 427, and
therefore, automatic srvloc dissection:
not port 427
Vendor Status:
The vendor has addressed this issue in ethereal 0.10.13, available
fordownload at:
<http://www.ethereal.com/download.html>
http://www.ethereal.com/download.html
CVE Information:
<http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2005-3184>
CAN-2005-3184
Disclosure Timeline:
12.10.05 - Initial vendor notification
12.10.05 - Initial vendor response
20.10.05 - Coordinated public disclosure
ADDITIONAL INFORMATION
The information has been provided by iDEFENSE.
The original article can be found at:
<http://www.idefense.com/application/poi/display?id=323>
http://www.idefense.com/application/poi/display?id=323
========================================
This bulletin is sent to members of the SecuriTeam mailing list.
To unsubscribe from the list, send mail with an empty subject line and body to:
list-unsubscribe@securiteam.com
In order to subscribe to the mailing list, simply forward this email to:
list-subscribe@securiteam.com
====================
====================
DISCLAIMER:
The information in this bulletin is provided "AS IS" without warranty of any
kind.
In no event shall we be liable for any damages whatsoever including direct,
indirect, incidental, consequential, loss of business profits or special
damages.
