Could you please let me know when it is available? On Wed, Sep 9, 2020 at 3:51 PM Mark J Cox <m...@openssl.org> wrote:
> They should be releasing their paper very soon (today). > > Regards, Mark > > On Wed, Sep 9, 2020 at 1:45 PM Dmitry Belyavsky <beld...@gmail.com> wrote: > > > > Is the description of the attack publicly available? > > > > On Wed, Sep 9, 2020 at 3:39 PM OpenSSL <open...@openssl.org> wrote: > >> > >> -----BEGIN PGP SIGNED MESSAGE----- > >> Hash: SHA512 > >> > >> OpenSSL Security Advisory [09 September 2020] > >> ============================================= > >> > >> Raccoon Attack (CVE-2020-1968) > >> ============================== > >> > >> Severity: Low > >> > >> The Raccoon attack exploits a flaw in the TLS specification which can > lead to > >> an attacker being able to compute the pre-master secret in connections > which > >> have used a Diffie-Hellman (DH) based ciphersuite. In such a case this > would > >> result in the attacker being able to eavesdrop on all encrypted > communications > >> sent over that TLS connection. The attack can only be exploited if an > >> implementation re-uses a DH secret across multiple TLS connections. > Note that > >> this issue only impacts DH ciphersuites and not ECDH ciphersuites. > >> > >> OpenSSL 1.1.1 is not vulnerable to this issue: it never reuses a DH > secret and > >> does not implement any "static" DH ciphersuites. > >> > >> OpenSSL 1.0.2f and above will only reuse a DH secret if a "static" DH > >> ciphersuite is used. These static "DH" ciphersuites are ones that start > with the > >> text "DH-" (for example "DH-RSA-AES256-SHA"). The standard IANA names > for these > >> ciphersuites all start with "TLS_DH_" but excludes those that start with > >> "TLS_DH_anon_". > >> > >> OpenSSL 1.0.2e and below would reuse the DH secret across multiple TLS > >> connections in server processes unless the SSL_OP_SINGLE_DH_USE option > was > >> explicitly configured. Therefore all ciphersuites that use DH in servers > >> (including ephemeral DH) are vulnerable in these versions. In OpenSSL > 1.0.2f > >> SSL_OP_SINGLE_DH_USE was made the default and it could not be turned > off as a > >> response to CVE-2016-0701. > >> > >> Since the vulnerability lies in the TLS specification, fixing the > affected > >> ciphersuites is not viable. For this reason 1.0.2w moves the affected > >> ciphersuites into the "weak-ssl-ciphers" list. Support for the > >> "weak-ssl-ciphers" is not compiled in by default. This is unlikely to > cause > >> interoperability problems in most cases since use of these ciphersuites > is rare. > >> Support for the "weak-ssl-ciphers" can be added back by configuring > OpenSSL at > >> compile time with the "enable-weak-ssl-ciphers" option. This is not > recommended. > >> > >> OpenSSL 1.0.2 is out of support and no longer receiving public updates. > >> > >> Premium support customers of OpenSSL 1.0.2 should upgrade to 1.0.2w. If > >> upgrading is not viable then users of OpenSSL 1.0.2v or below should > ensure > >> that affected ciphersuites are disabled through runtime configuration. > Also > >> note that the affected ciphersuites are only available on the server > side if a > >> DH certificate has been configured. These certificates are very rarely > used and > >> for this reason this issue has been classified as LOW severity. > >> > >> This issue was found by Robert Merget, Marcus Brinkmann, Nimrod Aviram > and Juraj > >> Somorovsky and reported to OpenSSL on 28th May 2020 under embargo in > order to > >> allow co-ordinated disclosure with other implementations. > >> > >> Note > >> ==== > >> > >> OpenSSL 1.0.2 is out of support and no longer receiving public updates. > Extended > >> support is available for premium support customers: > >> https://www.openssl.org/support/contracts.html > >> > >> OpenSSL 1.1.0 is out of support and no longer receiving updates of any > kind. > >> The impact of this issue on OpenSSL 1.1.0 has not been analysed. > >> > >> Users of these versions should upgrade to OpenSSL 1.1.1. > >> > >> References > >> ========== > >> > >> URL for this Security Advisory: > >> https://www.openssl.org/news/secadv/20200909.txt > >> > >> Note: the online version of the advisory may be updated with additional > details > >> over time. > >> > >> For details of OpenSSL severity classifications please see: > >> https://www.openssl.org/policies/secpolicy.html > >> -----BEGIN PGP SIGNATURE----- > >> > >> iQIzBAEBCgAdFiEEeVOsH7w9yLOykjk+1enkP3357owFAl9YzBsACgkQ1enkP335 > >> 7oyIxg/9FWuca3/s/lY6g6a5VTPIekZMOLRUnDyzS3YePQu/sEd1w81mKoTqU+6F > >> KQmliGqdRDk+KN8HDVd14kcLBukto8UKmkp9FpB5J4d2KK1I/Fg/DofJs6xUQYKb > >> 5rHRLB3DDoyHEBzEEIjcqYTTThXW9ZSByVK9SKpC78IRM/B2dfd0+j4hIB/kDC/E > >> G+wieFzexHQVdleVYT/VaJ6qS8AwvohBbt8h7yK0P6v/4vEm0spDbUmjWJBVUlUu > >> QZyELjj8XZR3YFxt3axSuJg3JSGYlaMzkt2+DVq4qEzeJLIydLK9J8p6RNwPhsJk > >> Rx0ez8P4N+5O7XmA0nHv3HyompdMgHlvykj8Ks4lNHVS02KKLi1jDtmOxl3Fm/hb > >> ZNOmjn7lulV1342pw4rWL3Nge3x0s0Q5zgBCm1mqLzzu/V1ksx8FJwGA1w2cH280 > >> dU9VedkC2wvFQije8pFrWH9l6N9Bh41DIEOnlBl0AL7IrbPdO6yMcD6vpR7hWjr3 > >> fx4hNJSAGzJ3i/NXlSj4eR/47zkjfJyEc8Drc2QgewyqXFrK20X/LOj8MqJlc+ry > >> pXZseh+XC8WaYDMV1ltrKvE2Ld9/0f3Ydc04AcDeu5SXPJG79ogzVnchZok7+XCj > >> RT+a3/ES45+CTfL5v27t5QJxJcxg4siLVsILfi0rIUv0IYgH2fU= > >> =U7OO > >> -----END PGP SIGNATURE----- > > > > > > > > -- > > SY, Dmitry Belyavsky > -- SY, Dmitry Belyavsky