Happy Holidays

If you have a moment (and are looking for a laugh) please take a look at my personal online holiday greeting to everyone in the IT business.

As the year draws to a close I have a lot to be thankful for. I find it's a good time to think about those who are less fortunate. If you can spare some money (it doesn't have to be much) these folks could sure use all of our help.

Happy holidays!

Common Vulnerabilities and Exposures - CVE

The list of Common Vulnerabilities and Exposures or CVE creates a list of standardized names for vulnerabilities and other information security exposures. The goal of CVE is to make it easier to share data across separate vulnerability databases and security tools. In the past if a vulnerability was discovered on one platform, say Windows and then also found in Linux it might have a different name or title while essentially being the same issue. This highlights a problem in the use of the word "vulnerability" in the security world today.

To many It professionals a "vulnerability" refers to any fact about a computer system that is a security concern in their network environment. The CVE web site cites the TCP/IP finger protocol as an example. Since the finger service reveals user information, many network operators put in place security policies that disallow finger from being run on some systems. That makes sense at the edge where finger service might be exploited, but there might be real uses for finger in other parts of the network. But because of the issue at the edge finger would be considered a "vulnerability" and described as such in that networks security policy.

Rather than referring to this as a vulnerability even though given different use cases different use cases this may not be considered to be vulnerabilities by everyone. So CVE introduces the term "exposure" to allow a service to be identified as potentially creating a security issue without necessarily being a problem.

CVE defines vulnerabilities and exposures like this:

A universal vulnerability is a state in a computing system (or set of systems) which either:

• allows an attacker to execute commands as another user
• allows an attacker to access data that is contrary to the specified access restrictions for that data
• allows an attacker to pose as another entity
• allows an attacker to conduct a denial of service

The following guidelines provide the basis for a definition of an "exposure." An exposure is a state in a computing system (or set of systems) which is not a universal vulnerability, but either:

• allows an attacker to conduct information gathering activities
• allows an attacker to hide activities
• includes a capability that behaves as expected, but can be easily compromised
• is a primary point of entry that an attacker may attempt to use to gain access to the system or data
• is considered a problem according to some reasonable security policy

Inexpensive Cisco Network Log Analysis

I saw a reference to an article titled Inexpensive Cisco Network Log Analysis by Mark Lachniet over at LinuxSecurity.com this morning. The log analysis article is well written and describes setting up Kiwi Syslog, configuring a PIX Firewall for syslog; and then configuring Sawmill log analyzer to provide reports based on the logged data.

Reading through the article the PIX configuration had one issue: the author omitted the "logging on" command that enables the logging process on the PIX.

If you are thinking of running Kiwi and the Sawmill analyzer I'd suggest starting out with a PIX Firewall that is at the same location as the syslog server. The PIX can generate quite a lot of log data and I'd suggest learning what your PIX will log given your network, users, and applications before trying to setup logging from a remote location.

How to configure your PIX Firewall for SSH

This (or click on the title above) is a paper I wrote on how to configure the PIX for SSH. It's really very easy to do.

What Model & Version of Linksys Hardware?

If you are trying to upgrade the firmware on your Linksys router and you are not sure which version of the hardware you have make sure to look at the label on the bottom of the router. The version number of the router is right next to the model number.

Good Disclosure...

I think that Konstantin Gavrilenko from Arhont Ltd.- Information Security did an outstanding job of documenting a Cisco PIX TCP Connection Prevention vulnerability. Cisco's response to this vulnerability announcement is here. He has documented what could be termed a resource attack on the PIX; forcing the Firewall to expend unnecessary resources reacting to a scripted packet. This attack could potentially slow user connections through the Firewall and in the extreme worst case possibly cause the Firewall to reload but does not expose the protected network. Gavrilenko has done an excellent job of communicating this issue that his work uncovered. I think even novice PIX Admins will be able to understand his findings.

I'd strongly suggest that all PIX Admins read the report and also go over the Cisco response. This is the first response that I've seen since PIX OS v7 came out. Cisco PSIRT present work arounds for both the v6.x and v7.x PIX operating systems. The vulnerability can best be exploited by an attacker on a inside interface.

One caution after reading the Cisco response; the first work around suggests that issuing a "clear xlate" or "clear local-host " will allow the PIX to pass connections again. I hope that most PIX Admins will appreciate that "clear xlate" will affect all connections going through the PIX were "clear local-host ..." only clears a single connection. Admins should use the "clear xlate" with caution on production networks.

Updated SANS top Twenty Vulnerabilities

The folks over at SANS.org released version 6 of their Top Twenty List of Critical Security Vulnerabilities today. When SANS started publishing their lists I always advised security analysts and in particular Firewall admins to strongly consider these vulnerabilities when creating and maintaining Firewall rules. Some time back the folks that compile the list started breaking out Windows vulnerabilities from others. Something that is new to the list this year is that the SANS team has further structured the list so as to look at Windows, networking, and cross platform ( or web application) vulnerabilities.

Black Hat no more?

I don't know if anyone saw this coming; Black Hat was acquired by CMP Media for about $10 million dollars. I know that when you look at the web site Black Hat lists consulting services available but I had never actually read anything about work they might have done. The Black Hat conference is the premiere annual security event. I think everyone is asking the question will Black Hat be able to maintain it's edge as part of a much larger (and seemingly much more conservative) media company? What's next, Ozzie Osbourne's music library being acquired by the Osmonds?