Vigil@nce: strongSwan, denial of service via IKE_SA_INIT
September 2008 by Vigil@nce
SYNTHESIS
An attacker can send a malicious IKE message in order to stop
strongSwan.
Gravity: 2/4
Consequences: denial of service of service
Provenance: internet client
Means of attack: no proof of concept, no attack
Ability of attacker: expert (4/4)
Confidence: confirmed by the editor (5/5)
Diffusion of the vulnerable configuration: high (3/3)
Creation date: 22/09/2008
IMPACTED PRODUCTS
– Unix - plateform
DESCRIPTION
The strongSwan program implements IPSec for Linux. It uses the GMP
(GNU Multiprecision Library) library for arithmetic operations on
large numbers. The mpz_export() and mpz_import() functions of GMP
convert large numbers.
The IKEv2 Charon daemon of strongSwan uses mpz_export() several times, but never checks if the return value is not NULL.
An attacker can send a IKE_SA_INIT message with a zero Key
Exchange payload, in order to force mpz_export() to return NULL.
When this pointer is dereferenced, the daemon stops.
A remote attacker can therefore create a denial of service.
CHARACTERISTICS
Identifiers: MU-200809-01, VIGILANCE-VUL-8122