pdnsd: Denial of Service and cache poisoning
Gentoo Linux Security Advisory
||GLSA 200901-03 / pdnsd
||January 11, 2009
||January 11, 2009: 01
All supported architectures
Two errors in pdnsd allow for Denial of Service and cache poisoning.
pdnsd is a proxy DNS server with permanent caching that is designed to
cope with unreachable DNS servers.
Two issues have been reported in pdnsd:
The p_exec_query() function in src/dns_query.c does not properly handle
many entries in the answer section of a DNS reply, related to a
"dangling pointer bug" (CVE-2008-4194).
The default value for query_port_start was set to 0, disabling UDP
source port randomization for outgoing queries (CVE-2008-1447).
An attacker could exploit the second weakness to poison the cache of
pdnsd and thus spoof DNS traffic, which could e.g. lead to the
redirection of web or mail traffic to malicious sites. The first issue
can be exploited by enticing pdnsd to send a query to a malicious DNS
server, or using the port randomization weakness, and might lead to a
Denial of Service.
Port randomization can be enabled by setting the "query_port_start"
option to 1024 which would resolve the CVE-2008-1447 issue.
All pdnsd users should upgrade to the latest version:
Code Listing 3.1: Resolution
# emerge --sync
# emerge --ask --oneshot --verbose ">=net-dns/pdnsd-1.2.7"