Archive for June, 2008

backtrack 3 released

Friday, June 20th, 2008

Any half decent sysadmin will routinely test the security of his or her own systems. A good, and sensible, sysadmin will follow up those tests with an independent security audit by a professional company – preferably one which is a member of a recognised industry body (such as CREST). Finding the holes in your security mechanisms (and there will be some – probably more than you will be happy about) before the bad guys do is essential if you want to sleep at night (and keep your job).

There are a huge number of security testing tools available for free if you know where to look. Most sysadmins keep a toolbox of their favourites (nmap, nessus, ettercap, dsniff et al.) to hand ready for testing any new build. But it can sometimes be difficult to know just which tool to use, and where to get it. Enter backtack. I first came across this collection of tools as recently as february 2006 and found it an excellent resource. Essentially backtrack is a collection of all the security testing tools you are likely to need packaged into one linux distribution. Think of it as a knoppix for security testing. A complete list of all the tools in the collection can be seen here.

Bactktrack Version 3 has just hit the streets. Get it here.

(Oh, and don’t think that using a toolset like this makes you a pen-tester. It doesn’t. What it might do is make you more security aware, and a better sysadmin.)

dental dos

Thursday, June 19th, 2008

On Tuesday 17 June, Craig Wriight, supposedly “Manager of Risk Advisory Services” in an Australian Company called “BDO Kendalls”, posted a rather odd note to Bugtraq and a few other security related lists titled “Hacking Coffee Makers”. In that posting he said that the Jura F90 Coffee maker (which can apparently be networked) was vulnerable to remote attack. His post said that the vulnerabilities allowed the attacker to:

“- Change the preset coffee settings (make weak or strong coffee);
- Change the amount of water per cup (say 300ml for a short black) and make a puddle;
- Break it by engineering settings that are not compatible (and making it require a service);”

but worse

“the software allows a remote attacker to gain access to the Windows XP system it is running on at the level of the user”.

Now I’ve been a subscriber to bugtraq for longer than I care to remember and I’ve seen some odd posts in the past – particularly around the beginning of April, but in June? I initially dismissed this as just one more nut trying to raise his profile in the security community, but since tuesday the story has been picked up by a range of commentators. Some have found the story simply amusing (slashdot – “All Your Coffee Are Belong To Us”), others such as CNET seem to have taken it only slightly more seriously. OK, the bits about attacking the coffee maker itself may be amusing, but there is a serious point here if Wright is correct in his statement that attacking the coffe jug gets you access to the windows system its management software runs on. Certainly Thor of Hammerofgod has taken the post seriously enough to question Wright’s professional judgement in posting details of a vulnerability before alerting the manufacturer.

The point to note is that as more and more consumer devices become networkable (and networked) then the attack surface gets larger and larger. And it is a fairly good bet that the manufacturer of (say) a networked microwave oven is not going to take network security as seriously as would the manufacturer of a router, NAS, or mainframe.

Oh and Wright has done it again today. His latest post to bugtraq is titled “Oral B SmartMonitor Information Disclosure Vulnerability and DoS”. It’s about a “remote exploitation of an information disclosure vulnerability in Oral B’s SmartGuide management system [that] allows attackers to obtain sensitive information.”

That’s right, he’s talking about a toothbrush.

Some people have way too much time on their hands.

xkcd on the openssl fiasco

Thursday, June 5th, 2008

I’ve had my attention drawn to Randall Munroe’s take on the openssl coding change problem.

openssl

Beautiful.

debian and the openssl flaw

Monday, June 2nd, 2008

Ben Laurie wrote about the Debian SSL problem a couple of weeks ago. That particular post has attracted a huge response which is well worth reading if you care about free open source software and/or privacy/security issues (or even if you don’t). The key point to take from the discussion is that about two years ago the Debian development team “fixed” a perceived problem in openssl and in so doing actually introduced a fairly serious vulnerability. The net result of this change was that anyone using Debian or a related distribution such as Ubuntu to generate a cryptographic key based on the “fixed” opensssl libraries actually left themselves open to compromise. To quote from the Debian advisory “the random number generator in Debian’s openssl package is predictable. This is caused by an incorrect Debian-specific change to the openssl package (CVE-2008-0166). As a result, cryptographic key material may be guessable…….. affected keys include SSH keys, OpenVPN keys, DNSSEC keys, and key material for use in X.509 certificates and session keys used in SSL/TLS connections.”

Fortunately, it seems that GPG keys are not affected (and in any case, my own key was generated some time ago and not on a Debian based system) but this is pretty serious nonetheless and means that a great many people (myself included) have been relying on keys which it turns out are vulnerable to attack. I have now regenerated all the keys I suspect were vulnerable, but that does not leave me feeling very comfortable about past usage.

I don’t want to denigrate the Debian team in any way, but I can’t help but agree with Ben Laurie’s view that the proper place to fix any perceived flaw in an open source product, particularly one as important as a security critical component, is in the upstream package – not in the distribution.

recursion: see recursion

Monday, June 2nd, 2008

I have written about how I use one of my slugs to backup my internal files via rsync over ssh. Well it turns out I made a pretty silly mistake in my rsync options. I thought I’d been careful in specifying the files I specifically wanted excluded from the backup (ephemeral stuff, thumbnail images, some caches such as my browser cache etc.) but I missed one crucial directory and it bit me – and sent the slug’s load average through the roof.

GNOME 2.22 introduced GVFS, a new network-transparent virtual filesystem layer. GVFS is a userspace virtual file system with backends for protocols like SFTP and FTP. GVFS creates a (hidden) directory called .gvfs in your home directory and uses this as a mount point when you open a connection via SSH, FTP, SMB, WebDAV etc from the “Places -> Connect to Server” menu option. So if you open an SFTP connection to a server called “slug”, it will mount that connection in .gvfs. Try it yourself.

Now guess what I had mounted on my desktop at the time my rsync cron job ran. The slug spent some frantic time copying itself to itself until I noticed that it seemed to be inordinately busy, diagnosed the problem and managed to kill the rsync and clear up the mess.