Windows 7 And Vista Crash Via SMB Exploit

vista_dx10_bsod

[Laurent Gaffié] has discovered an exploit that affects Windows Vista, Windows 7, and possibly Windows Server 2008 (unconfirmed). This method attacks via the NEGOTIATE PROTOCOL REQUEST which is the first SMB query sent. The vulnerability is present only on Windows versions that include Server Message Block 2.0 and have the protocol enabled. A successful attack requires no local access to the machine and results in a Blue Screen of Death.

[Laurent] has a proof of concept available with his writeup in the form of a python script (please, white hat use only). There is no patch for this vulnerability but disabling the SMB protocol will protect your system until one is available.

Update: According to the Microsoft advisory this vulnerability could lead to code execution, making it a bit worse than we thought. On the bright side, they claim that the final version of Windows 7 is not open to this attack, only Windows Vista and Windows Server 2008.

[via Full Disclosure]

[picture: Inquirer]

The GIFAR Image Vulnerability


Researchers at NGS Software have come up with a method to embed malicious code into a picture. When viewed, the picture could send the attacker the credentials of the viewer. Social sites like Facebook and Myspace are particularly at risk, but the researchers say that any site which includes log ins and user uploaded pictures could be vulnerable. This even includes some bank sites.

The attack is simply a mashup of a GIF picture and a JAR (Java applet). The malicious JAR is compiled and then combined with information from a GIF. The GIF part fools the browser into opening it as a picture and trusting the content. The reality is, the Java VM recognizes the JAR part and automatically runs it.

The researchers claim that there are multiple ways to deal with this vulnerability. Sun could restrict their Virtual Machine or web applications could continually check and filter these hybrid files, but they say it really needs to be addressed as an issue of browser security. They think that it is not only pictures at risk, but nearly all browser content.
More details on how to create these GIFARs will be presented at this week’s Black Hat conference in Las Vegas.

Securing DNS On OSX


It’s been a few weeks since [Dan Kaminsky] announced the nature of the DNS vulnerability and allowed 30 days of non-disclosure for patches to be applied before details of the exploit went public. Unfortunately, the details were leaked early and it didn’t take long for a functional exploit to be released into the wild. Since then, many ISPs have taken steps to prevent their users from falling victim to the attack, and BIND, the widely-used DNS protocol implementation, was updated to minimize the threat. Even then, there were reports of a version of the attack being actively used on AT&T’s DNS servers.

Mac OSX uses a BIND implementation but as of yet, Apple has not released a patch updating the system (Microsoft, on the other hand, patched this up on July 8). As a result, machines running OSX are at risk of being exploited. Individual users are less likely to be targeted, since the attacks are directed towards servers, but it’s not a smart idea to leave this vulnerability open. [Glenn Fleishman] has published a way to update BIND on OSX manually, rather than waiting on Apple to patch it themselves. It requires Xcode and a bit of terminal work, but it’s a relatively painless update. When we tried it, the “make test” step skipped a few tests and told us to run “bin/tests/system/ifconfig.sh up”. That allowed us to re-run the tests and continue the update without further interruption. [Fleischman] warns that people who manually update BIND may break the official update, but he will update his instructions when it happens with any possible workarounds. Unfortunately, this fix only works for 10.5 but alternative, yet less effective methods may work for 10.4 and earlier.

If you’d like to know if your preferred DNS servers are vulnerable or not, you can use the DNS checker tool from Doxpara. As an alternative to your ISP’s DNS servers, you can use OpenDNS, which many prefer for its security features and configuration options.

Major DNS Issue Causes Multivendor Patch Day


Earlier this year, our friend [Dan Kaminsky] discovered a major DNS issue that could allow hackers to compromise name servers and clients easily. The vulnerability involves cache poisoning, and [Kaminsky] plans to publish the full details of the vulnerability on August 6th. However, he has already begun his work to control it, alerting major authorities early on of the vulnerability.

As a result, engineers from many major technology vendors quickly began working on coordinated patches for DNS servers. The patches were all released today; vendors and a CERT advisory urge organizations to apply them today, before the vulnerability becomes common knowledge. More details on the DNS issue can be found in the executive overview (PDF file). [Rich Mogull] interviewed [Dan] for the Network Security Podcast. It doesn’t detail the attack but points out that services that use port randomization like OpenDNS are unaffected and that Bind8 is being deprecated.

UPDATE: Here’s the audio from this morning’s press conference.

[image: Flickr / d70focus ]