Nokia Information for VU#924812

---[Nokia Notice]---
NOKIA CUSTOMER CONFIDENTIAL, GGSN RELEASE 1 VULNERABILITY

Under exceptional circumstances Nokia GGSN release 1 is
potentially vulnerable to a "Denial Of Service" style of
attack from a malicious user equipped with a computer and a
mobile phone. When the vulnerability is exploited the GGSN
restarts. There is no damage to the configuration, but some
charging data may be lost. Changing a normal Access Point to
tunneled (GRE or IP in IP) prevents the attacks from mobile
user side.

The same applies for the Gi interface though routers and
firewalls would normally drop this kind of packets. The
problem has been detected and reported by @stake and has been
reproduced by Nokia in collaboration with @stake. Nokia and
@stake are jointly working to eliminate the problem.

This vulnerability is corrected in IPSO version 3.4 and all
subsequent versions. Thus, GGSN release 2 is not vulnerable,
GGSN release 1 is. Nokia advices all the customers still
running GGSN release level 1 to upgrade on GGSN release level 2.

As an interim measure operators can perform the following
preventative configuration changes to their networks. Ensure
that all IP packets with non standard IP options are dropped
by boarder firewalls on the Gi interface. Within the Gn
network ensure that the GTP aware firewall (if present) also
drops all encapsulated IP packets with non standard IP
options. This may introduce latency however it will mitigate
against the attack until the patch has been fully deployed
and tested.

Due to the severity of this vulnerability @stake has
confirmed that they will not be releasing this information
publicly on their research page (http://www.atstake.com/research/)
until Nokia has confirmed that all affected operators have fully
patched and tested all affected elements. However @stake would
ideally like to release this information no later than 1st June
2003.


Neither @stake nor Nokia are aware of this attack being used
in the wild as it was discovered by @stake within a lab
environment and subsequently tested on a number of operators
for whom they have worked for.
---[End Nokia Notice]---

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