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Cisco Security Response: Multiple Vulnerabilities in OpenSSL
library
http://www.cisco.com/warp/public/707/cisco-s
r-20061108-openssl.shtml
Revision 1.0
For Public Release 2006 November 08 1600 UTC (GMT)
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Cisco Response
==============
This is the Cisco PSIRT response to the multiple security
advisories
published by The OpenSSL Project. The vulnerabilities are as
follows:
* RSA Signature Forgery (CVE-2006-4339), described in
http:
//www.openssl.org/news/secadv_20060905.txt
* ASN.1 Denial of Service Attacks (CVE-2006-2937,
CVE-2006-2940),
described in http:
//www.openssl.org/news/secadv_20060928.txt
* SSL_get_shared_ciphers() buffer overflow
(CVE-2006-3738), also in
http:
//www.openssl.org/news/secadv_20060928.txt
leavingcisco.com
* SSLv2 Client Crash (CVE-2006-4343), also in
http:
//www.openssl.org/news/secadv_20060928.txt
As of this publication, there are no workarounds available
for any of
these vulnerabilities, but it may be possible to mitigate
some of the
exposure. This Security Response lists the status of each
product or
application when considered individually. However, in cases
where
multiple applications are running on the same computer, a
vulnerability in one application or component can compromise
the
entire system. This compromise can then be leveraged against
applications that would otherwise be unaffected. Therefore,
users
must consider all applications when determining their
exposure to
these vulnerabilities. Cisco strongly recommends that
customers
update all vulnerable applications and components to provide
the
greatest protection from the listed vulnerabilities. Cisco
will
update this document in the event of any changes.
Additional Information
======================
RSA Signature Forgery
+--------------------
During the CRYPTO 2006 conference, which was held August
20-24, 2006,
Daniel Bleichenbacher presented a method for forging RSA
signatures.
The attack requires two conditions to be successful:
* The keys use 3 (three) as one of the RSA exponents.
* The signature verification algorithm has vulnerable
implementation.
Notes describing this attack are at
http://www.imc.org/ietf-openpgp/mail-archive/msg14307.
html
The signature verification implementation vulnerability
consists of
improper verification of PKCS-1 padded data. Any software
with this
vulnerability might accept a forged signature, but only if
the key
that is being forged has 3 (three) as one of the exponents.
ASN.1 Denial of Service Attacks
+------------------------------
Two vulnerabilities have been uncovered by an ASN.1 test
suite
developed by Dr. S. N. Henson. Both of these
vulnerabilities, if
exploited, can cause denial of service. The vulnerabilities
are as
follows:
* Parsing of certain invalid ASN.1 structures can result
in an
infinite loop that can consume system memory. This issue
does not
affect OpenSSL versions prior to 0.9.7. This is assigned
CVE
number CVE-2006-2937.
* Specially crafted public keys can take a
disproportionate amount
of time to be processed. This is assigned CVE number
CVE-2006-2940.
SSL_get_shared_ciphers() buffer overflow
+---------------------------------------
A specially crafted list of ciphers can be used to overrun a
buffer.
This vulnerability has been assigned CVE ID of CVE-2006-3738
and was
discovered by Tavis Ormandy and Will Drewry from Google
Security
Team.
SSLv2 Client Crash
+-----------------
SSL server can send malformed packet during SSLv2 connection
negotiation that can crash an SSL client. This vulnerability
is
assigned CVE ID CVE-2006-4343.
Products Affected by OpenSSL Vulnerabilites
+------------------------------------------
Note: This is not a definitive list. Cisco continues to
verify other
products and the list will be updated accordingly. The
following
products are affected by the OpenSSL issues listed in this
Security
Response:
* Cisco Global Site Selector (GSS 4480, 4490, 4491, 4492)
- Cisco
bug ID is CSCsg22734. The fix is
expected in the 2.0(1) release that is targeted for
February
2007.
* Cisco MDS 9500 Multilayer Director - Cisco bug ID is
CSCsg01963. Availability of fixed software has not been
determined
yet.
* Cisco IDS - Cisco bug ID is CSCsg09619. Availability of
fixed
software has not been determined yet.
* Cisco ONS 15454 - Cisco bug ID is CSCsg16571. The fix is
contained
in version 8.0 and later.
* Cisco Access Registrar - Cisco bug ID is CSCsg17943.
Availability
of fixed software has not been determined yet.
* Cisco Secure ACS - Cisco bug ID is CSCsg24311.
Availability of
fixed software has not been determined yet.
* Cisco Security Agent - Cisco bug ID is CSCsg46092. Fixed
libraries
are provided by the hotfix 5.1.0.79. Other supported
software
releases will be updated in an upcoming releases.
* Cisco Call Manager - Cisco bug IDs are CSCsg04397 and
CSCsg04386.
Only software releases 4.x and higher are affected. None
of the
previous releases are vulnerable. The fixes will be
available in
software release 5.1(1) currently targeted for
2006-Dec-11.
* Cisco Unified Presence Server - Cisco bug ID CSCsg51110.
Fixed
software will be available in CUPS 1.0(3), currently
targeted for
2006-Nov-16.
* Cisco Security MARS - Cisco bug ID is CSCsg51304. The
fixes will
be available in software release 4.2.3, which is
expected in
2006-December.
* Cisco CSS 11500 Series Content Services Switches - Cisco
bug ID is
CSCek57074. Fixed software is available as releases
7.50.3.4S and
8.10.2.6S.
* Cisco Wireless LAN Controller - Cisco bug ID is
CSCsg59589. The
fixes will be available in upcoming software releases
4.0.x,
targeted for 2006-Dec-18, and 3.2.x, targeted for
2007-January-31.
* Cisco Application and Content Networking System (ACNS) -
Cisco bug
ID is CSCsf97055 and CSCsg55732. Availability of fixed
software
has not been determined yet.
* Cisco Application Control Engine Module - Cisco bug ID
is
CSCsg36592. Availability of fixed software has not been
determined
yet.
* Cisco Wide Area File Services Software (WAFS) - Cisco
bug ID is
CSCsg55738. Availability of fixed software has not been
determined
yet.
* Cisco Wide Area Application Services (WAAS) Software -
Cisco bug
ID is CSCsg55742. Availability of fixed software has not
been
determined yet.
* Cisco SIP Proxy Server - Cisco bug ID is CSCsg56292.
Availability
of fixed software has not been determined yet.
* CiscoWorks Common Services - Cisco bug IDs are
CSCsg58599 and
CSCsg58607. Some Cisco management products integrate
CiscoWorks
Common Services into their general installation and
runtime
environments. To verify, navigate the path Server
Configuration >
About the Server > Applications and Versions in the
CiscoWorks
Server. Availability of fixed software has not been
determined
yet.
* CiscoWorks Common Management Foundation (CMF was
referred to as
Common Services before the release of CiscoWorks 3.0) -
Cisco bug
ID is CSCsg58592. Some Cisco management products
integrate
CiscoWorks Common Services into their general
installation and
runtime environments. To verify, navigate the path
Server
Configuration > About the Server > Applications
and Versions in
the CiscoWorks Server. Availability of fixed software
has not been
determined yet.
Products Not Affected by OpenSSL Vulnerabilites
+----------------------------------------------
Note: This list is not a definitive list. Cisco continues
to verify
other products and the list will be updated accordingly. The
following products are confirmed not vulnerable.
* Cisco IOS
* Cisco IOS XR
* Cisco IP Interoperability and Collaboration System
(IPICS)
* Cisco ASA/PIX/FWSM - While these products contain the
OpenSSL
libraries, they do not make use of the vulnerable code.
Nonetheless, the software library has been updated to
avoid any
potential issues in the future.
+ For Cisco PIX/ASA, this is tracked by Cisco bug IDs
CSCsg21727, CSCsg52606, CSCsg07425, and CSCsg07405.
Software
releases with updated libraries will be 6.3.6,
7.0.7,
7.1.2.26, and 7.2.1.21 and later.
+ For Cisco FWSM, this is tracked by Cisco bug ID
CSCsg52485,
and the fixed libraries are expected in one of
upcoming 3.1
interim releases.
Workaround
==========
SSL is predominately used for securing HTTP traffic, but is
also used
to secure other TCP traffic, such as SMTP, POP3, IMAP, and
FTP.
Generally speaking, there is no workaround for these issues,
but
mitigation is possible. By blocking affected protocols at
the edge of
your network and by allowing only legitimate IP addresses to
connect
to your devices, it is possible to lower your exposure to
these
vulnerabilities.
Another option, which could reduce the security of your
system, is to
revert to non-secure variants of the protocols. In that
case, you
will not be affected by the vulnerabilities described here,
but your
traffic will be sent in clear text and, if intercepted, an
adversary
will be able to read it or even modify it while in transit.
THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS AND
DOES NOT IMPLY ANY
KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF
THE
INFORMATION ON THE DOCUMENT OR MATERIALS LINKED FROM THE
DOCUMENT IS
AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR
UPDATE THIS
DOCUMENT AT ANY TIME.
Revision History
================
+----------------------------------------+
| Revision | | Initial |
| 1.0 | 2006-November-08 | public |
| | | release. |
+----------------------------------------+
Cisco Security Procedures
=========================
Complete information on reporting security vulnerabilities
in Cisco
products, obtaining assistance with security incidents, and
registering to receive security information from Cisco, is
available
on Cisco's worldwide website at
http://www.cisco.com/en/US/produc
ts/products_security_vulnerability_policy.html
This includes instructions for press inquiries regarding
Cisco
security notices. All Cisco security advisories are
available at
http://www.cisco.com/go
/psirt
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