Remote exploitation of an input validation vulnerability in the OSPF
protocol dissectors within Ethereal, as included in various vendors
operating system distributions, could allow attackers to crash the
vulnerable process or potentially execute arbitrary code.
The affected Ethereal component is used to analyse Open Shortest Path
First (OSPF) Interior Gateway Protocol (IGP), as specified in RFC-2178.
The vulnerability specifically exists due to no bounds checking being
performed in the dissect_ospf_v3_address_prefix() function. This
function takes user-supplied binary data and attempts to convert it into
a human readable string. This function uses a fixed length buffer on
the stack to store the constructed string but performs no checks on the
length of the input. If the generated output length from the input
exceeds the size of the buffer, a stack-based overflow occurs.
III. ANALYSIS
Successful exploitation allows remote attackers to perform a DoS against
a running instance of Ethereal and may, under certain conditions,
potentially allow the execution of arbitrary code. As the overflow
string is generated from a format string converting binary values into
their hexadecimal (base 16) equivalent characters, it can contain only a
limited subset of all possible characters, and the length of an
overflow is only able to be controlled to within the three characters.
This may prevent exploit ability on some platforms; however, it may be
possible that these constraints will not prevent exploitation on
others.
IV. DETECTION
iDefense has confirmed the existence of this vulnerability in the
ethereal-0.10.12 RPM from Red Hat Fedora Core 3. It is suspected that
previous versions containing the OSPF dissector code are also
vulnerable.
V. WORKAROUND
Disable the OSPF packet dissector in Ethereal by performing the
following actions as the user invoking Ethereal, typically root.
The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2005-3651 to this issue. This is a candidate for inclusion in
the CVE list (http://cve.mitre.org), which standardizes names for
security problems.
Permission is granted for the redistribution of this alert
electronically. It may not be edited in any way without the express
written consent of iDefense. If you wish to reprint the whole or any
part of this alert in any other medium other than electronically, please
email customerservice@xxxxxxxxxxxx for permission.
Disclaimer: The information in the advisory is believed to be accurate
at the time of publishing based on currently available information. Use
of the information constitutes acceptance for use in an AS IS condition.
There are no warranties with regard to this information. Neither the
author nor the publisher accepts any liability for any direct, indirect,
or consequential loss or damage arising from use of, or reliance on,
this information.
[NEWS] Cisco IOS Malformed OSPF Packet Causes Reload ... Get your security news from a reliable source. ... Service attack from a malformed OSPF packet.... The vulnerability is only present in Cisco IOS release trains based on ... Cisco has made free software available to address this vulnerability.... (Securiteam)
[NEWS] OpenSSH Challenge-Response Buffer Overflow (Update) ... The following security advisory is sent to the securiteam mailing list, and can be found at the SecuriTeam web site: http://www.securiteam.com ... the platforms on which this vulnerability may be exploited. ... their platforms invulnerable to exploitation....Mandrake Secure Linux:... (Securiteam)
