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CVE-2016-7055

MEDIUMCVSS 5.9/10EPSS 14.34%

Last modified

CVE-2016-7055 is a medium-severity vulnerability rated 5.9/10 on the CVSS scale. 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. EPSS estimates a 14.34% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
5.9/10

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability
14.34%

96.2th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

VendorProductVersions
OpensslOpenssl>= 1.0.2, < 1.0.2k
OpensslOpenssl>= 1.1.0, < 1.1.0c
NodejsNode.Js>= 4.0.0, <= 4.1.2
NodejsNode.Js>= 4.2.0, < 4.7.3
NodejsNode.Js>= 6.0.0, <= 6.8.1
NodejsNode.Js>= 6.9.0, < 6.9.5
NodejsNode.Js>= 7.0.0, < 7.5.0

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2016-7055?
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.
How severe is CVE-2016-7055?
CVE-2016-7055 has a CVSS score of 5.9/10 (MEDIUM severity). The EPSS model estimates a 14.34% probability of exploitation in the next 30 days.
How do I fix CVE-2016-7055?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST