PowerDNS Recursor: DNS Cache Poisoning

1. Gentoo Linux Security Advisory

Advisory Reference	GLSA 200804-22 / pdns-recursor
Release Date	April 18, 2008
Latest Revision	August 21, 2008: 03
Impact	normal
Exploitable	remote

Package	Vulnerable versions	Unaffected versions	Architecture(s)
net-dns/pdns-recursor	< 3.1.6	>= 3.1.6	All supported architectures

Related bugreports: #215567, #231335

Synopsis

Use of insufficient randomness in PowerDNS Recursor might lead to DNS cache poisoning.

2. Impact Information

Background

The PowerDNS Recursor is an advanced recursing nameserver.

Description

Amit Klein of Trusteer reported that insufficient randomness is used to calculate the TRXID values and the UDP source port numbers (CVE-2008-1637). Thomas Biege of SUSE pointed out that a prior fix to resolve this issue was incomplete, as it did not always enable the stronger random number generator for source port selection (CVE-2008-3217).

Impact

A remote attacker could send malicious answers to insert arbitrary DNS data into the cache. These attacks would in turn help an attacker to perform man-in-the-middle and site impersonation attacks.

3. Resolution Information

Workaround

There is no known workaround at this time.

Resolution

All PowerDNS Recursor users should upgrade to the latest version:

Code Listing 3.1: Resolution

# emerge --sync
# emerge --ask --oneshot --verbose ">=net-dns/pdns-recursor-3.1.6"

4. References

Updated April 18, 2008

Summary: This is a Gentoo Linux Security Advisory

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