Bind DOS vulnerability (CVE-2011-0414)

Published: 2011-02-23
Last Updated: 2011-02-23 18:39:52 UTC
by Manuel Humberto Santander Pelaez (Version: 1)
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Internet Software Consortium published today an advisory for the BIND software. For versions 9.7.1-9.7.2-P3, when a server that is authoritative for a domain (i.e. owns the SOA record) process a successful domain transfer operation (IXFR) or a dynamic update, there is a small window of time where this processing combined with a high amount of queries can cause a deadlock, which makes the DNS server stop processing further requests.

Bind is one of the preferred targets for attackers on the Internet. If you have bind installed in your company, please remember the following basic security measures:

  • Only allow IXFR transfers from known secondary servers of your domain. You don't want to let people know all the list of public ip address associated with your domain
  • Keep separated your internal DNS information from your external DNS information. Some DNS provides information about private addresses used inside the corporate network.
  • Allow recursive requests only from your internal DNS. If you allow recursive requests from the Internet, you are exposed to a distributed denial of service.

To solve the problem, upgrade to BIND 9.7.3. More information at 

-- Manuel Humberto Santander Peláez | | | msantand at isc dot sans dot org

Keywords: Bind CVE20110414
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Windows 7 Service Pack 1 out

Published: 2011-02-23
Last Updated: 2011-02-23 16:17:41 UTC
by Johannes Ullrich (Version: 1)
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Microsoft made the first service pack for Windows 7 and 2008 R2 available for public download. This service pack is essentially a "roll up patch" including most security patches and hot fixes released so far.

Aside from patches, service packs typically include some improvements and new features. From a security point of view, RemoteFX may be of interest. RemoteFX extends RDP to allow a more "complete" remote desktop access including access to USB drives from example, more in line with virtual machine desktop clients that can use a local drive to load data on a remote virtual machine.

DirectAccess has been improved as well. DirectAccess requires the use of IPv6, and with SP 1, 6to4 as well as ISATAP are supported.

The RemoteFX and DirectAccess enhancements only affect Windows 2008 R2, not Windows 7.

Some twitter reports suggest that the service pack install may fail if bitlocker is used. If you experience any issues: Please let us know.

Johannes B. Ullrich, Ph.D.
SANS Technology Institute

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