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MaraDNS: CNAME Denial of Service


1.  Gentoo Linux Security Advisory

Version Information

Advisory Reference GLSA 200801-16 / maradns
Release Date January 29, 2008
Latest Revision January 29, 2008: 01
Impact normal
Exploitable remote
Package Vulnerable versions Unaffected versions Architecture(s)
net-dns/maradns < >= All supported architectures

Related bugreports: #204351


MaraDNS is prone to a Denial of Service vulnerability impacting CNAME resolution.

2.  Impact Information


MaraDNS is a package that implements the Domain Name Service (DNS) with resolver and caching ability.


Michael Krieger reported that a specially crafted DNS could prevent an authoritative canonical name (CNAME) record from being resolved because of an "improper rotation of resource records".


A remote attacker could send specially crafted DNS packets to a vulnerable server, making it unable to resolve CNAME records.

3.  Resolution Information


Add "max_ar_chain = 2" to the "marac" configuration file.


All MaraDNS users should upgrade to the latest version:

Code Listing 3.1: Resolution

# emerge --sync
# emerge --ask --oneshot --verbose ">=net-dns/maradns-"

4.  References


Page updated January 29, 2008

Summary: This is a Gentoo Linux Security Advisory

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