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
