Date: Wed, 30 Jan 2013 11:33:53 -0700 From: Kurt Seifried <kseifried@...hat.com> To: oss-security@...ts.openwall.com CC: Florian Weimer <fweimer@...hat.com>, Salvatore Bonaccorso <carnil@...ian.org> Subject: Re: CVE request: hs-tls: Basic constraints vulnerability -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 01/30/2013 03:59 AM, Florian Weimer wrote: > On 01/20/2013 01:32 PM, Salvatore Bonaccorso wrote: > >> For hs-tls (TLS/SSL implementation in haskell) it was announced >> the following advisory: >> >> ----cut---------cut---------cut---------cut---------cut---------cut----- >> >> Hi cafe, >> >> this is a security advisory for tls-extra < 0.6.1 which are all >> vulnerable to bad certificate validation. >> >> Some part of the certificate validation procedure were missing >> (relying on the work-in-progress x509 v3 extensions), and because >> of this anyone with a correct end-entity certificate can issue >> certificate for any arbitrary domain, i.e. acting as a CA. >> >> This problem has been fixed in tls-extra 0.6.1, and I advise >> everyone to upgrade as soon as possible. >> >> Despite a very serious flaw in the certificate validation, I'm >> happy that the code is seeing some audits, and would want to >> thanks Ertugrul Sylemez for the findings . >> >>  https://github.com/vincenthz/hs-tls/issues/29 >> ----cut---------cut---------cut---------cut---------cut---------cut----- > >> > I believe an alternative description of the impact is: > hs-tls-extras does not check the Basic Constraints attribute of a > certificate in certificate chain procession, and any certificate is > treated as a CA certificate, which means that anyone who has a > valid certificate can use it to sign another one (with an arbitrary > subject DN/domain name embedded into it) and have it accepted by > hs-tls. This eventually allows MITM attacks on TLS connections. > > Kurt, is this more to your liking? 8-) Yup! Please use CVE-2013-0243 for this issue. - -- Kurt Seifried Red Hat Security Response Team (SRT) PGP: 0x5E267993 A90B F995 7350 148F 66BF 7554 160D 4553 5E26 7993 -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.13 (GNU/Linux) iQIcBAEBAgAGBQJRCWeRAAoJEBYNRVNeJnmTYuwQANBYOXHg6tppHjpRDrhYrR6i yv1MZahWRYRT1cYFiX6dG+6MwAqCtHtLOTaaN5bAGP2BviczTK/WuLdo6axAvR1P 83XCYk4ewxT+HHLwZXUAJHMmFQrEuplhe0FzpL2wuBquPQ4B9jBWz1+qfm4oR14H 2DGsI5rHiA88AKzDSf1QwaE/0SwEWplff8f4fvd3kU0wi044HzyuM9VKrkhkroWz cHwX4rdJTEV1mTEr8O1myVpXF2tuMmzuzXFMYd42NuqzC1cv72upXJMnbWxq85QG qEM2GozkTHeG5kBzqN1R9lAPEXcXhe8dXg6lTYp8XanTjyf5wHCrcV1T6jJhzDLA nWM37ehcZ0vZwrTUhkoM9JSLHf/FSLObR9N1qQA8lbNcUn1VNXOelToIcdM84Mcr RqBROOa8UX9fg8rMeE9akUxgTmEGHUhDKcWq5Tkf6J8l/EZEYON4JjRVf+n3Cw17 nrUJ93HnHO2S5AcUXohK12Uq3YfrWxR041fLkwUNH1aOQy2Xomc4T/86WTRw3BNc aEEuwKiDu9O9tu5Fy8H/LfuX9geYjpg3i3OXwYzBy8LT87S2H5FvtmMFfCfKrVCR +YCh8eJ4T6NimQQfZO5sez9SINyNLaccPnSCFYeMmnidIIjDgySVlDLQuY2kfpxL dFY6FOh/+/fXtDnkaAmp =DpBg -----END PGP SIGNATURE-----
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