[c-nsp] Cisco Security Advisory: IronPort Encryption Appliance / PostX and PXE Encryption Vulnerabilities

Wed Jan 14 12:15:00 EST 2009

IronPort PXE Encryption is an e-mail encryption solution that is
designed to secure e-mail communications without the need for a
Public Key Infrastructure (PKI) or special agents on receiving
systems. When an e-mail message is targeted for encryption, the PXE
encryption engine on an IronPort e-mail gateway encrypts the original
e-mail message as an HTML file and attaches it to a notification
e-mail message that is sent to the recipient. The per-message key
used to decrypt the HTML file attachment is stored on a local
IronPort Encryption Appliance, PostX software installation or the
Cisco Registered Envelope Service, which is a Cisco-managed software
service.

PXE Encryption Privacy Vulnerabilities
+-------------------------------------

The IronPort PXE Encryption solution is affected by two
vulnerabilities that could allow unauthorized individuals to view the
contents of secure e-mail messages. To exploit the vulnerabilities,
attackers must first intercept secure e-mail messages on the network
or via a compromised e-mail account.

IronPort Encryption Appliance Administration Interface Vulnerabilities
+---------------------------------------------------------------------

IronPort Encryption Appliance devices contain two vulnerabilities
that could allow unauthorized users to gain access to the IronPort
Encryption Appliance administration interface and modify other users'
settings. These vulnerabilities do not affect Cisco Registered
Envelope Service users.

Cisco has released free software updates that address these
vulnerabilities. There are no workarounds for the vulnerabilities
that are described in this advisory.

This advisory is posted at:

http://www.cisco.com/warp/public/707/cisco-sa-20090114-ironport.shtml

Affected Products
=================

Vulnerable Products
+------------------

The following IronPort Encryption Appliance/PostX versions are
affected by these vulnerabilities:

  * All PostX 6.2.1 versions prior to 6.2.1.1
  * All PostX 6.2.2 versions prior to 6.2.2.3
  * All IronPort Encryption Appliance/PostX 6.2.4 versions prior to 6.2.4.1.1
  * All IronPort Encryption Appliance/PostX 6.2.5 versions
  * All IronPort Encryption Appliance/PostX 6.2.6 versions
  * All IronPort Encryption Appliance/PostX 6.2.7 versions prior to 6.2.7.7
  * All IronPort Encryption Appliance 6.3 versions prior to 6.3.0.4
  * All IronPort Encryption Appliance 6.5 versions prior to 6.5.0.2

The version of software that is running on an IronPort Encryption
Appliance is located on the About page of the IronPort Encryption
Appliance administration interface.

Note: Customers should contact IronPort support to determine which
software fixes are applicable for their environment. Please consult
the Obtaining Fixed Software section of this advisory for more
information.

Products Confirmed Not Vulnerable
+--------------------------------

IronPort C, M and S-Series appliances are not affected by these
vulnerabilities. Although C-Series appliances can be configured to
use a local IronPort Encryption Appliance for per-message key
retention, the C-Series appliances are not vulnerable. The Cisco
Registered Envelope Service is not vulnerable.

No other Cisco products are currently known to be affected by these
vulnerabilities.

Details
=======

Note: IronPort tracks bugs using an internal system that is not
available to customers. The IronPort bug tracking identifiers are
provided for reference only.

PXE Encryption Privacy Vulnerabilities
+-------------------------------------

Individual PXE Encryption users are vulnerable to two message privacy
vulnerabilities that could allow an attacker to gain access to
sensitive information. All the vulnerabilities require an attacker to
first intercept a secure e-mail message as a condition for successful
exploitation. Attackers can obtain secure e-mail messages by
monitoring a network or a compromised user e-mail account.

The IronPort Encryption Appliance contains a logic error that could
allow an attacker to obtain the unique, per-message decryption key
that is used to protect the content of an intercepted secure e-mail
message without user interaction. Using the decryption key, an
attacker could decrypt the contents of the secure e-mail message.
This vulnerability is documented in IronPort bug 8062 and has been
assigned Common Vulnerabilities and Exposures (CVE) identifier
CVE-2009-0053.

By modifying the contents of intercepted secure e-mail messages or by
forging a close copy of the e-mail message, it may be possible for an
attacker to convince a user to view a modified secure e-mail message
and then cause the exposure of the user's credentials and message
content. Please see the Workarounds section for more information on
mitigations available to reduce exposure to these phishing-style
attacks. This vulnerability is documented in IronPort bug 8149 and
has been assigned Common Vulnerabilities and Exposures (CVE)
identifier CVE-2009-0054.

IronPort Encryption Appliance Administration Interface Vulnerabilities
+---------------------------------------------------------------------

The administration interface of IronPort Encryption Appliance devices
contains a cross-site request forgery (CSRF) vulnerability that could
allow an attacker to modify a user's IronPort Encryption Appliance
preferences, including their user name and personal security pass
phrase, if the user is logged into the IronPort Encryption Appliance
administration interface. Exploitation of the vulnerability will not
allow an attacker to change a user's password. This vulnerability is
documented in IronPort bug 5806 and has been assigned Common
Vulnerabilities and Exposures (CVE) identifier CVE-2009-0055.

The administration interface of IronPort Encryption Appliance devices
also contains a cross-site request forgery (CSRF) vulnerability that
could allow an attacker to execute a command and modify a user's
IronPort Encryption Appliance preferences, including their user name
and personal security pass phrase, under certain circumstances when a
user logs out of the IronPort Encryption Appliance administration
interface. Exploitation of the vulnerability will not allow an
attacker to change a user's password. This vulnerability is
documented in IronPort bug 6403 and has been assigned Common
Vulnerabilities and Exposures (CVE) identifier CVE-2009-0056.

Vulnerability Scoring Details
=============================

Cisco has provided scores for the vulnerabilities in this advisory
based on the Common Vulnerability Scoring System (CVSS). The CVSS
scoring in this Security Advisory is done in accordance with CVSS
version 2.0.

CVSS is a standards-based scoring method that conveys vulnerability
severity and helps determine urgency and priority of response.

Cisco has provided a base and temporal score. Customers can then
compute environmental scores to assist in determining the impact of
the vulnerability in individual networks.

Cisco has provided an FAQ to answer additional questions regarding
CVSS at:

http://www.cisco.com/web/about/security/intelligence/cvss-qandas.html

Cisco has also provided a CVSS calculator to help compute the
environmental impact for individual networks at:

http://intellishield.cisco.com/security/alertmanager/cvss

PXE Encryption Message Decryption Vulnerability - IronPort Bug 8062

CVSS Base Score - 7.1
    Access Vector - Network
    Access Complexity - Medium
    Authentication - None
    Confidentiality Impact - Complete
    Integrity Impact - None
    Availability Impact - None

CVSS Temporal Score - 5.9
    Exploitability - Functional
    Remediation Level - Official Fix
    Report Confidence - Confirmed

PXE Encryption Phishing Vulnerabilities - IronPort Bug 8149

CVSS Base Score - 6.1
    Access Vector - Network
    Access Complexity - High
    Authentication - None
    Confidentiality Impact - Complete
    Integrity Impact - Partial
    Availability Impact - None

CVSS Temporal Score - 5
    Exploitability - Functional
    Remediation Level - Official Fix
    Report Confidence - Confirmed

IronPort Encryption Appliance CSRF Vulnerability - IronPort Bug 5806

CVSS Base Score - 5.8
    Access Vector - Network
    Access Complexity - Medium
    Authentication - None
    Confidentiality Impact - Partial
    Integrity Impact - Partial
    Availability Impact - None

CVSS Temporal Score - 4.8
    Exploitability - Functional
    Remediation Level - Official Fix
    Report Confidence - Confirmed

IronPort Encryption Appliance Logout Action CSRF Vulnerability - IronPort Bug 6403

CVSS Base Score - 5.8
    Access Vector - Network
    Access Complexity - Medium
    Authentication - None
    Confidentiality Impact - Partial
    Integrity Impact - Partial
    Availability Impact - None

CVSS Temporal Score - 4.8
    Exploitability - Functional
    Remediation Level - Official Fix
    Report Confidence - Confirmed

Impact
======

PXE Encryption Privacy Vulnerabilities
+-------------------------------------

Successful exploitation of these vulnerabilities could allow an
attacker to obtain user credentials and view the contents of
intercepted secure e-mail messages, which could result in the
disclosure of sensitive information.

IronPort Encryption Appliance Administration Interface Vulnerabilities
+---------------------------------------------------------------------

Successful exploitation of these vulnerabilities could allow an
attacker to access user accounts on an IronPort Encryption Appliance
device, which could result in the modification of user preferences.

Software Versions and Fixes
===========================

When considering software upgrades, also consult
http://www.cisco.com/go/psirt and any subsequent advisories to determine
exposure and a complete upgrade solution.

Workarounds
===========

There are no workarounds for the vulnerabilities that are described
in this advisory.

There are mitigations available to help prevent exploitation of the
PXE Encryption phishing-style vulnerability. Phishing attacks can be
greatly reduced if DomainKeys Identified Mail (DKIM) and Sender
Policy Framework (SPF) are implemented on IronPort e-mail gateways to
help ensure message integrity and source origin. Additionally, the
PXE Encryption solution contains an anti-phishing Secure Pass Phrase
feature to ensure that secure notification e-mail messages are valid.
This feature is enabled by recipients when configuring their PXE user
profile. Cisco has released a best practices document that describes
several techniques to mitigate against the phishing-style attacks
that is available at the following link:

http://www.cisco.com/web/about/security/intelligence/bpiron.html

Obtaining Fixed Software
========================

Cisco has released free software updates that address these
vulnerabilities. The affected products in this advisory are directly
supported by IronPort, and not via the Cisco TAC organization.
Customers should contact IronPort technical support at the link below
to obtain software fixes. IronPort technical support will assist
customers in determining the correct fixes and installation
procedures. Customers should direct all warranty questions to
IronPort technical support.

Do not contact psirt at cisco.com or security-alert at cisco.com for
software upgrades.

http://www.ironport.com/support/contact_support.html

Exploitation and Public Announcements
=====================================

The Cisco PSIRT is not aware of any public announcements or malicious
use of the vulnerabilities that are described in this advisory.

J.B. Snyder of Brintech reported a method for obtaining PXE
Encryption user credentials via a phishing-style attack to Cisco.

All other vulnerabilities were discovered by Cisco or reported by
customers.

Status of this Notice: FINAL
============================

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.

A stand-alone copy or Paraphrase of the text of this document that
omits the distribution URL in the following section is an
uncontrolled copy, and may lack important information or contain
factual errors.

Distribution
============

This advisory is posted on Cisco's worldwide website at:

http://www.cisco.com/warp/public/707/cisco-sa-20090114-ironport.shtml

In addition to worldwide web posting, a text version of this notice
is clear-signed with the Cisco PSIRT PGP key and is posted to the
following e-mail and Usenet news recipients.

  * cust-security-announce at cisco.com
  * first-bulletins at lists.first.org
  * bugtraq at securityfocus.com
  * vulnwatch at vulnwatch.org
  * cisco at spot.colorado.edu
  * cisco-nsp at puck.nether.net
  * full-disclosure at lists.grok.org.uk
  * comp.dcom.sys.cisco at newsgate.cisco.com

Future updates of this advisory, if any, will be placed on Cisco's
worldwide website, but may or may not be actively announced on
mailing lists or newsgroups. Users concerned about this problem are
encouraged to check the above URL for any updates.

Revision History
================

+---------------------------------------+
| Revision |                 | Initial  |
| 1.0      | 2009-January-14 | 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/products/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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