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The September 2012 Cisco Security Advisory Bundle is Coming Soon!

As previously discussed here on the Cisco Security blog, the Cisco Product Security Incident Response Team (PSIRT) follows a twice-per-year schedule for disclosing high-severity security vulnerabilities in Cisco IOS Software. The next Cisco IOS Software Security Advisory Bundle will be released on the 26th of September at 16:00 GMT. Our Security Vulnerability Policy describes the schedule best:

In direct response to customer feedback, Cisco releases bundles of Cisco IOS Software Security Advisories on the fourth Wednesday 16:00 GMT of the month in March and September of each calendar year. This schedule applies to the disclosure of Cisco IOS Software vulnerabilities and does not apply to the disclosure of vulnerabilities in other Cisco products.

We offer several convenient and timely ways to learn of new
Cisco Security Advisories and Cisco Security Advisory Bundles.

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Product Security Incident Managers…A Closer Look

Product security covers quite a broad spectrum of knowledge areas within the realm of technologies applied to enable communications in this highly connected world. However, there is a natural tendency to first focus on the basic capabilities of the product itself. But later, questions arise such as “Is the product in operation vulnerable and if yes, what are the next steps to protecting against the vulnerability?” or “What can I do if I suspect a security issue with a product?” As much as one would like to sustain 100% immunity against any vulnerability or issue, events happen, inherent product weaknesses are discovered or new attack vectors and methods arise to expose ways to compromise a product’s operation or behavior. At Cisco, the people that rapidly converge on such occurrences or the potential for such occurrences are the Incident Managers (IM) who reside at the core of the Product Security Incident Response Team (PSIRT) within Security Intelligence Operations (SIO). I think it is fascinating how well this team seamlessly executes with the precision, efficacy, and timeliness on a day-in-day-out basis covering a large array of complex hardware, software, and technologies. The IM focuses on driving the underlying processes around the discovery of security disclosures and issues related to Cisco products and networks. I hope you will find that this article provides you with an informative and personal perspective on the IM role that is integral to the ongoing efforts essential to protecting the Cisco customer.

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Cisco IOS Security Advisory Bundle – It’s That Time Again

September 28, 2011 at 9:15 am PST

Once again it’s time for Cisco’s semi-annual Cisco IOS Software Security Advisory Bundled Publication. Today’s edition of the bundle contains a total of nine IOS-related advisories and one non-IOS advisory for the Cisco Unified Communications Manager (CUCM) family of products. Included in the 10 Security Advisories are a total of 19 Cisco Bug IDs, each one representing an individual vulnerability.

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Introducing the Cisco IOS Software Checker

A new tool called the Cisco IOS Software Checker is now available on the Cisco Security Intelligence Operations (SIO) portal.  This tool introduces a feature that has been long-requested from our customers and will make Cisco product security information much easier to consume and digest.

Security Advisories that are published by the Cisco Product Security Incident Response Team (PSIRT) provide detailed information about security vulnerabilities in Cisco products, including mitigations, affected products and vulnerable and fixed versions of software. Security Advisories affecting Cisco IOS include a table that provides a list of affected Cisco IOS release trains and fixed versions for those trains. Our customers have long asked us for ways to simplify identification of affected software in this table, and so we have developed the Cisco IOS Software Checker for this very purpose. This tool leverages our internal databases to easily provide affected software information without requiring you to manually process the fixed software table.

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Cisco Investigation for TCP Split-Handshake Issue Reported by NSS

Updated May 9th: After a thorough investigation of the TCP Split Handshake issue raised by NSS Labs, Cisco has confirmed that the Cisco ASA firewall is not susceptible to this issue. In all test cases examined, the ASA operates as expected, providing protection in its default configuration against the Split-Handshake as defined in the original TCP Split Handshake paper. As a result, the Cisco PSIRT closed this investigation on May 4th.

Cisco appreciates the extended engagement and data provided by NSS Labs as we’ve worked through these scenarios. During two recent visits to NSS Labs, Cisco was presented with a number of scenarios, including new test cases that deviated from the original Split-Handshake scenario. The Cisco PSIRT collected traces and provided feedback to NSS Labs on all scenarios. In each case, Cisco demonstrated successful network protection through the default ASA configuration or the implementation of firewall policies that are fully supported, documented and used pervasively in enterprise deployments.

As always vulnerability reports should continue to be reported to the PSIRT organization (psirt@cisco.com). Cisco customers are encouraged to contact their account manager with any questions.


Recently there’s been some activity in the press regarding an NSS Labs report on potential vulnerabilities in Next-Generation Firewalls (NGFW). The Cisco Adaptive Security Appliance (ASA) was one of the products mentioned as vulnerable to these attacks. Based on the investigation of this issue to date, the data indicates that Cisco customers are not exposed to this issue. As always, should the vulnerability be confirmed the Cisco Product Security Incident Response Team (PSIRT) will investigate, drive remediation and disclose per our normal communication channels. (PSIRT Vulnerability Policy)

On April 12th, NSS Labs published a report regarding vulnerabilities on a number of firewalls, including Cisco’s ASA product line. The full report has a hefty $3500 price tag, but NSS does provide a free (with registration) “Remediation Guide,” for users of these firewalls.

The NSS Labs Remediation Guide incorrectly lists the Cisco ASA as vulnerable to the TCP Split Handshake attack, and also mentions that there are no steps available to customers to mitigate or remediate this attack.

Following an investigation over the course of several months, involving well over a dozen Cisco engineers from various teams and working in conjunction with NSS Labs, no vulnerability of this nature has been observed on Cisco products. The following products have been investigated:

  • Cisco ASA
  • Cisco IOS Firewall
  • Cisco Intrusion Protection (IPS) Appliances

It’s important to note that the NSS Labs report focuses only on one attack called the TCP Split Handshake, which is a third means to initiate TCP sessions that combines features of both the three-way handshake and the simultaneous-open connection.

However, the goal of this post isn’t to discuss the technical details of TCP handshakes, but rather to present what Cisco has done and is doing to investigate the impact to our products and protect our customers.

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