Patch Tuesday sees serious DNS flaws fixed

Nothing marked critical, but some very important patches issued.

Microsoft

‘s latest ‘Patch Tuesday’ round of security updates for once contains no bulletins marked as ‘critical’, but some of the four updates labelled ‘important’ address major issues posing serious threats to web users worldwide.

Two of the patches fix problems with

Exchange Server

and

Windows Explorer

, while a third covers four separate vulnerabilities in

SQL Server

, which could help reduce the large numbers of sites being compromised via SQL-related flaws.

The most significant of the updates fixes a systemic security hole in the implementation of the DNS system, the name resolution method at the heart of networking and the internet. The problem was uncovered several months ago by researcher Dan Kaminsky of

IOActive

, who found that some issues with randomisation and the way DNS selects ports to attach to could be exploited to spoof DNS responses and redirect traffic to malicious sites. After some high-level cooperation with many of the major providers of DNS software, the flaws are now being disclosed prior to a presentation on the topic at next month’s

Black Hat

conference in Las Vegas.

Details of the problem are at

US-Cert


here

or at the

SANS Internet Storm Center


here

. Admins running DNS server implementations are advised to check with their providers for updates, as a wide range of products including

BIND

are thought to be affected by the issue and many have now provided fixes. No known exploit attempts have yet been reported. More coverage of the issue is at the

BBC


here

, while a report in

The Register


here

claims the problem was spotted several years ago but ignored.

A patch issued by

Microsoft

may also have affected users of the highly popular

Zone Alarm

range of anti-malware and security products, which could be prevented from connecting to the web after the patch is applied. Details and workaround methods are

here

.

The full rundown of the latest patches from

Microsoft

is in the company’s monthly bulletin

here

.

Posted on 10 July 2008 by

Virus Bulletin