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Cisco Security Advisory

IronPort Encryption Appliance / PostX and PXE Encryption Vulnerabilities

Advisory ID: cisco-sa-20090114-ironport

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20090114-ironport

Revision 1.0

For Public Release 2009 January 14 16:00  UTC (GMT)

Related Resources:


Summary

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://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20090114-ironport.

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

Calculate the environmental score of 8062

CVSS Base Score - 7.1

Access Vector

Access Complexity

Authentication

Confidentiality Impact

Integrity Impact

Availability Impact

Network

Medium

None

Complete

None

None

CVSS Temporal Score - 5.9

Exploitability

Remediation Level

Report Confidence

Functional

Official-Fix

Confirmed

PXE Encryption Phishing Vulnerabilities - IronPort Bug 8149

Calculate the environmental score of 8149

CVSS Base Score - 6.1

Access Vector

Access Complexity

Authentication

Confidentiality Impact

Integrity Impact

Availability Impact

Network

High

None

Complete

Partial

None

CVSS Temporal Score - 5

Exploitability

Remediation Level

Report Confidence

Functional

Official-Fix

Confirmed

IronPort Encryption Appliance CSRF Vulnerability - IronPort Bug 5806

Calculate the environmental score of 5806

CVSS Base Score - 5.8

Access Vector

Access Complexity

Authentication

Confidentiality Impact

Integrity Impact

Availability Impact

Network

Medium

None

Partial

Partial

None

CVSS Temporal Score - 4.8

Exploitability

Remediation Level

Report Confidence

Functional

Official-Fix

Confirmed

IronPort Encryption Appliance Logout Action CSRF Vulnerability - IronPort Bug 6403

Calculate the environmental score of 6403

CVSS Base Score - 5.8

Access Vector

Access Complexity

Authentication

Confidentiality Impact

Integrity Impact

Availability Impact

Network

Medium

None

Partial

Partial

None

CVSS Temporal Score - 4.8

Exploitability

Remediation Level

Report Confidence

Functional

Official-Fix

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@cisco.com or security-alert@cisco.com for software upgrades.

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

Customers with Service Contracts

Customers with contracts should obtain upgraded software through their regular update channels. For most customers, this means that upgrades should be obtained through the Software Center on Cisco's worldwide website at http://www.cisco.com.

Customers Using Third-Party Support Organizations

Customers whose Cisco products are provided or maintained through prior or existing agreements with third-party support organizations, such as Cisco Partners, authorized resellers, or service providers should contact that support organization for guidance and assistance with the appropriate course of action in regards to this advisory.

The effectiveness of any workaround or fix is dependent on specific customer situations, such as product mix, network topology, traffic behavior, and organizational mission. Due to the variety of affected products and releases, customers should consult with their service provider or support organization to ensure any applied workaround or fix is the most appropriate for use in the intended network before it is deployed.

Customers Without Service Contracts

Customers who purchase direct from Cisco but do not hold a Cisco service contract, and customers who purchase through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should acquire upgrades by contacting the Cisco Technical Assistance Center (TAC). TAC contacts are as follows.

  • +1 800 553 2447 (toll free from within North America)
  • +1 408 526 7209 (toll call from anywhere in the world)
  • e-mail: tac@cisco.com

Customers should have their product serial number available and be prepared to give the URL of this notice as evidence of entitlement to a free upgrade. Free upgrades for non-contract customers must be requested through the TAC.

Refer to http://www.cisco.com/en/US/support/tsd_cisco_worldwide_contacts.html for additional TAC contact information, including localized telephone numbers, and instructions and e-mail addresses for use in various languages.

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://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20090114-ironport

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@cisco.com
  • first-bulletins@lists.first.org
  • bugtraq@securityfocus.com
  • vulnwatch@vulnwatch.org
  • cisco@spot.colorado.edu
  • cisco-nsp@puck.nether.net
  • full-disclosure@lists.grok.org.uk
  • comp.dcom.sys.cisco@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 1.0

2009-January-14

Initial 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/web/about/security/psirt/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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