Vigil@nce - glibc: infinite loop of getnetbyname
December 2014 by Vigil@nce
This bulletin was written by Vigil@nce : http://vigilance.fr/offer
SYNTHESIS OF THE VULNERABILITY
An attacker can generate an infinite loop in applications using
the getnetbyname() function of the glibc, in order to trigger a
denial of service.
Impacted products: Unix (platform)
Severity: 1/4
Creation date: 15/12/2014
DESCRIPTION OF THE VULNERABILITY
The getnetbyname() function of the glibc converts a network name
to a netent structure. For example "2.1.in-addr.arpa" is converted
to the network 1.2/16.
The /etc/nsswitch.conf file indicates the list of methods to use
to perform the resolution. For example, to resolve networks with
the DNS service: "networks: dns".
However, if a DNS server returns an empty reply, an infinite loop
occurs in the getanswer_r() function of the
resolv/nss_dns/dns-network.c file.
An attacker can therefore generate an infinite loop in
applications using the getnetbyname() function of the glibc, in
order to trigger a denial of service.
ACCESS TO THE COMPLETE VIGIL@NCE BULLETIN
http://vigilance.fr/vulnerability/glibc-infinite-loop-of-getnetbyname-15790