Re: [ GLSA 200512-04 ] Openswan, IPsec-Tools: Vulnerabilities in ISAK MP Protocol implementation
On Mon, 12 Dec 2005, Thierry Carrez wrote:
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Gentoo Linux Security Advisory GLSA 200512-04
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http://security.gentoo.org/
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Severity: Normal
Title: Openswan, IPsec-Tools: Vulnerabilities in ISAKMP Protocol
implementation
Date: December 12, 2005
Bugs: #112568, #113201
ID: 200512-04
Openswan and IPsec-Tools suffer from an implementation flaw which may
allow a Denial of Service attack.
That is correct (for openswan)
Impact
======
A remote attacker can create a specially crafted packet using 3DES with
an invalid key length, resulting in a Denial of Service attack, format
string vulnerabilities or buffer overflows.
That's a copy and paste from the IPsec proto testsuite.
1) It conflicts with the above comment that this is only a DOS
2) It's incorrect (for openswan)
Workaround
==========
Avoid using "aggressive mode" in ISAKMP Phase 1, which exchanges
information between the sides before there is a secure channel.
In fact, you would to both have aggressive mode enabled AND know the PSK.
If you have those two enabled, you are vulnerable to a MITM anyway, since
any client knowing the PSK can pretend to be the IPsec security gateway.
Paul