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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 =========================================================================== AUSCERT Security Bulletin ASB-2013.0016 A vulnerability has been identified in GnuTLS 8 February 2013 =========================================================================== AusCERT Security Bulletin Summary --------------------------------- Product: GnuTLS Operating System: Windows UNIX variants (UNIX, Linux, OSX) Impact/Access: Access Privileged Data -- Remote with User Interaction Resolution: Patch/Upgrade CVE Names: CVE-2013-1619 Member content until: Sunday, March 10 2013 OVERVIEW A vulnerability has been identified in GnuTLS prior to versions 3.1.7, 3.0.28 and 2.12.23. [1] IMPACT The vendor has provided the following description regarding this vulnerability: "Nadhem Alfardan and Kenny Paterson devised an attack that recovers some bits of the plaintext of a GnuTLS session that utilizes that CBC ciphersuites, by using timing information. In order for the attack to work the client must operate as follows. It connects to a server, it sends some (encrypted) data that will be intercepted by the attacker, who will terminate the client's connection abnormally (i.e. the client will receive a premature termination error). The client should repeat that, multiple times." [1] MITIGATION The vendor has provided the following mitigations which includes the application of a patch: "Do not enable the CBC ciphersuites, prefer ARCFOUR or GCM modes. Upgrade to the latest GnuTLS version (3.1.7, 3.0.28, or 2.12.23)." [1] REFERENCES [1] TLS CBC padding timing attack http://www.gnutls.org/security.html#GNUTLS-SA-2013-1 AusCERT has made every effort to ensure that the information contained in this document is accurate. However, the decision to use the information described is the responsibility of each user or organisation. The decision to follow or act on information or advice contained in this security bulletin is the responsibility of each user or organisation, and should be considered in accordance with your organisation's site policies and procedures. AusCERT takes no responsibility for consequences which may arise from following or acting on information or advice contained in this security bulletin. =========================================================================== Australian Computer Emergency Response Team The University of Queensland Brisbane Qld 4072 Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). On call after hours for member emergencies only. =========================================================================== -----BEGIN PGP SIGNATURE----- Comment: http://www.auscert.org.au/render.html?it=1967 iQIVAwUBURSDEu4yVqjM2NGpAQKfBBAAiydDedY2z17Esh+2tRJGkShty/K5pIT+ AOwvsdz/pZwLvwLbOxnJpwpPQzZJkwewa1Hot6TzeKoosHNnvdBEknvSRm1yGLzA s2it5tiXQtjXw7iI8BRFzzE/jyehdwy6TZJ92fnkpyH3vj0IqZ9iUKj54tzcomFV KrBExCFVUAMi6sMvpvMUl6Hjn5KYpz8f07/kJne83tLkixONvBOdNHvdZX6dHbcr Fs5epW2b3OWyoF7LKCg5NOm1KllkQ7Yr5dvs0kB2Das4CsZWXbgCQlCDjFhXu22Y jHSRYc1fcT3qFxZ4gMsnMB+CHz+eSvLgY1r/+qto5U+ShXCm9pZagR8EOvH7Lw+G du/RQRJpd2AZWEHoyVtD6z/E+/eCU6Jx/Qm/21Rix8J/6t7h+a4cLvF0BSngOk8H O9esq3Yg5yovrq/n4kfVGTDibQb3A8xeP5FX7/SJdXeOuJCZ5dpt2/HA0GiNqGnZ Ofwz0czrQZnrn6pUH0EGMVqU0ZIwIDsIm5piPyU69VmTFf7uvsECe1lx1k0lYlES BG/bVclTGyWbmTyYtZjO8idFXLDTe+OA8ymtAOS82n6ttbq6wpKL0aeP5gsnU01O 3VXMJ1ENVPtnm6Ricel2Tol3xVPPitUJzMmAe54n/6G5X6GoLU6mH7xNznn0ltCG zkQivyWgUDk= =ka4D -----END PGP SIGNATURE-----