Bug 91421 – dev-libs/libtomcrypt: ECC Signature Scheme Vulnerability

• Product: Gentoo Security
• Status: RESOLVED FIXED

[Description Jean-François Brunette (RETIRED) 2005-05-04 05:41:37 UTC]

Description:
A vulnerability with an unknown impact has been reported in LibTomCrypt.

The vulnerability is caused due to an unspecified error in the signature scheme used for ECC (Elliptic Curve Cryptography).

The vulnerability has been reported in version 1.02. Prior versions may also be affected.

Solution:
The vulnerability has been fixed in the CVS repository.

[Comment 1 Carsten Lohrke (RETIRED) 2005-05-04 06:03:53 UTC]

eh, sorry

[Comment 2 Sune Kloppenborg Jeppesen (RETIRED) 2005-05-04 08:32:38 UTC]

vapier please advise.

[Comment 3 SpanKY 2005-05-04 17:24:05 UTC]

we'll have to wait for an upstream release since tom doesnt provide a public cvs server

for now i'll just package.mask it

[Comment 4 Jean-François Brunette (RETIRED) 2005-05-29 09:25:30 UTC]

jaervosz is not available to watch the bug so I'll check regularly upstream for
the new versions.

[Comment 5 Jean-François Brunette (RETIRED) 2005-06-08 06:22:28 UTC]

The new version should be comign tommorow (June 9th)

[Comment 6 Jean-François Brunette (RETIRED) 2005-06-09 08:36:11 UTC]

1.03 has been released
http://libtomcrypt.org/download.html

vapier please bump

[Comment 7 SpanKY 2005-06-10 16:52:55 UTC]

1.03 now in portage

[Comment 8 Jean-François Brunette (RETIRED) 2005-06-10 17:10:06 UTC]

thanks Vapier

arches please mark stable

[Comment 9 SpanKY 2005-06-10 18:17:33 UTC]

i took care of that too

[Comment 10 Jean-François Brunette (RETIRED) 2005-06-10 18:28:07 UTC]

Sorry, I couldn't know because of the lag

[Comment 11 Thierry Carrez (RETIRED) 2005-06-11 01:21:20 UTC]

Without more info I vote 1/2 NO

[Comment 12 Matthias Geerdsen (RETIRED) 2005-06-11 08:44:37 UTC]

updated section from secunia:

Description:
A vulnerability has been reported in LibTomCrypt, which can be exploited by
malicious people to create valid signatures without the private key.

The vulnerability is caused due to a mathematical error in the implementation of
the El Gamal signature algorithm. This can be exploited to create valid
signatures and sign arbitrary messages without the private key via an
application using the ECC (Elliptic Curve Cryptosystem) signature scheme routines.

The vulnerability has been reported in version 1.02. Prior versions may also be
affected.


________
CAN-2005-1600
Description:
A "mathematical flaw" in the implementation of the El Gamal signature algorithm
for LibTomCrypt 1.0 to 1.0.2 allows attackers to generate valid signatures
without having the private key.


________
http://www.securityfocus.org/archive/1/397649

LibTomCrypt version <=1.02 contained weak signature scheme used
with ECC keys, allowing trivial signature forgeries.

Description:
------------
During recent cryptographic review by the author, a mathematical flaw
was found within the implementation of the El Gamal signature algorithm
used in LibTomCrypt versions <=1.02 An attacker can create a valid
random signature by selecting a random value for a, and then computing
(a^-1)C (where the inverse is modulo the order of the curve),
essentially allowing an attacker to sign arbitrary messages without the
private key.

[Comment 13 Thierry Carrez (RETIRED) 2005-06-16 09:07:47 UTC]

I tend to vote NO. libtomcrypt is not used in any portage package...

[Comment 14 Jean-François Brunette (RETIRED) 2005-06-16 14:49:17 UTC]

please vote

[Comment 15 Sune Kloppenborg Jeppesen (RETIRED) 2005-06-16 22:11:02 UTC]

I tend to vote NO too. 

[Comment 16 Thierry Carrez (RETIRED) 2005-06-17 02:52:47 UTC]

Anybody thinking yes, please reopen.