CVE-2016-7055
Vulnérabilité non évaluée
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.
Gravité et risque d'exploitation
CVE-2016-7055 obtient un score CVSS de 0.0/10, soit une gravité non évaluée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 14.22 %, ce qui la place devant 96.6 % des CVE référencées.
Que faire ?
- Vérifiez si le produit concerné est présent sur votre parc.
- Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
- À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
- Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.
Références
- https://access.redhat.com/errata/RHSA-2018:2185
- https://access.redhat.com/errata/RHSA-2018:2186
- http://www.oracle.com/technetwork/security-advisory/cpujan2018-3236628.html
- 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
- http://www.oracle.com/technetwork/security-advisory/cpuoct2017-3236626.html
- https://www.tenable.com/security/tns-2017-04
- https://security.gentoo.org/glsa/201702-07
- http://www.oracle.com/technetwork/security-advisory/cpujul2017-3236622.html
- http://www.securityfocus.com/bid/94242
- https://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbgn03752en_us
- https://access.redhat.com/errata/RHSA-2018:2187
- https://www.openssl.org/news/secadv/20161110.txt
- http://www.securitytracker.com/id/1037261
- https://www.oracle.com/technetwork/security-advisory/cpuapr2019-5072813.html
