CVE-2016-7055

openssl: Carry propagating bug in Montgomery multiplication

Published May 4, 2017 CVSS 3.1 · 5.9 Medium EPSS 14.2% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

Sign in to view the affected projects.

Advisories

Source ID Title
Ubuntu USN Ubuntu USN USN-3181-1 OpenSSL vulnerabilities
History
Type Values Removed Values Added
Metrics epss

{'score': 0.05438}

epss

{'score': 0.07992}

Weaknesses

Sources

Status
PUBLISHED
Assigner
mitre
Published
Updated
Aug 6, 2024, 1:50 AM
Reserved
Aug 23, 2016, 12:00 AM
Status
Modified
Published
May 4, 2017, 8:29 PM
Modified
Jun 17, 2026, 12:52 AM
Severity
Low
Public date
Oct 11, 2016, 12:00 AM