OpenSSL CVE-2017-3738 Information Disclosure Vulnerability

description-logoDescription

Severity: LowThis issue has been reported in a previous OpenSSL security advisory and a fixwas provided for OpenSSL 1.0.2. Due to the low severity no fix was released atthat time for OpenSSL 1.1.0. The fix is now available in OpenSSL 1.1.0h.There is an overflow bug in the AVX2 Montgomery multiplication procedureused in exponentiation with 1024-bit moduli. No EC algorithms are affected.Analysis suggests that attacks against RSA and DSA as a result of this defectwould be very difficult to perform and are not believed likely. Attacksagainst DH1024 are considered just feasible, because most of the worknecessary to deduce information about a private key may be performed offline.The amount of resources required for such an attack would be significant.However, for an attack on TLS to be meaningful, the server would have to sharethe DH1024 private key among multiple clients, which is no longer an optionsince CVE-2016-0701.This only affects processors that support the AVX2 but not ADX extensionslike Intel Haswell (4th generation).Note: The impact from this issue is similar to CVE-2017-3736, CVE-2017-3732and CVE-2015-3193.OpenSSL 1.1.0 users should upgrade to 1.1.0hOpenSSL 1.0.2 users should upgrade to 1.0.2nThis issue was reported to OpenSSL on 22nd November 2017 by David Benjamindeveloped by Andy Polyakov of the OpenSSL development team.ReferencesURL for this Security Advisory:https://www.openssl.org/news/secadv/20180327.txtNote: the online version of the advisory may be updated with additional detailsover time.For details of OpenSSL severity classifications please see:https://www.openssl.org/policies/secpolicy.html

affected-products-logoAffected Applications

OpenSSL

CVE References

CVE-2017-3738