CVE-2016-7055

LOW

Description

There is a carry propagating bug in the Broadwell-specific Montgomery multiplication procedure in OpenSSL 1.0.2 and 1.1.0 before 1.1.0c that handles input lengths divisible by, but longer than 256 bits. Analysis suggests that attacks against RSA, DSA and DH private keys are impossible. This is because the subroutine in question is not used in operations with the private key itself and an input of the attacker's direct choice. Otherwise the bug can manifest itself as transient authentication and key negotiation failures or reproducible erroneous outcome of public-key operations with specially crafted input. Among EC algorithms only Brainpool P-512 curves are affected and one presumably can attack ECDH key negotiation. Impact was not analyzed in detail, because pre-requisites for attack are considered unlikely. Namely multiple clients have to choose the curve in question and the server has to share the private key among them, neither of which is default behaviour. Even then only clients that chose the curve will be affected.

References

http://www.oracle.com/technetwork/security-advisory/cpujan2018-3236628.html

http://www.oracle.com/technetwork/security-advisory/cpujul2017-3236622.html

http://www.oracle.com/technetwork/security-advisory/cpuoct2017-3236626.html

http://www.securityfocus.com/bid/94242

http://www.securitytracker.com/id/1037261

https://access.redhat.com/errata/RHSA-2018:2185

https://access.redhat.com/errata/RHSA-2018:2186

https://access.redhat.com/errata/RHSA-2018:2187

https://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbgn03752en_us

https://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbhf03744en_us

https://security.FreeBSD.org/advisories/FreeBSD-SA-17:02.openssl.asc

https://security.gentoo.org/glsa/201702-07

https://www.openssl.org/news/secadv/20161110.txt

https://www.oracle.com/technetwork/security-advisory/cpuapr2019-5072813.html

https://www.tenable.com/security/tns-2017-04

Details

Source: MITRE

Published: 2017-05-04

Updated: 2019-07-02

Type: CWE-320

Risk Information

CVSS v2.0

Base Score: 2.6

Vector: AV:N/AC:H/Au:N/C:N/I:N/A:P

Impact Score: 2.9

Exploitability Score: 4.9

Severity: LOW

CVSS v3.0

Base Score: 5.9

Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Impact Score: 3.6

Exploitability Score: 2.2

Severity: MEDIUM