CVE-2017-3732

BN_mod_exp may produce incorrect results on x86_64

Published May 4, 2017 CVSS 3.1 · 5.9 Medium EPSS 15.4% KEV · Not listed
Description
There is a carry propagating bug in the x86_64 Montgomery squaring procedure in OpenSSL 1.0.2 before 1.0.2k and 1.1.0 before 1.1.0d. No EC algorithms are affected. Analysis suggests that attacks against RSA and DSA as a result of this defect would be very difficult to perform and are not believed likely. Attacks against DH are considered just feasible (although very difficult) because most of the work necessary to deduce information about a private key may be performed offline. The amount of resources required for such an attack would be very significant and likely only accessible to a limited number of attackers. An attacker would additionally need online access to an unpatched system using the target private key in a scenario with persistent DH parameters and a private key that is shared between multiple clients. For example this can occur by default in OpenSSL DHE based SSL/TLS ciphersuites. Note: This issue is very similar to CVE-2015-3193 but must be treated as a separate problem.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
EUVD EUVD EUVD-2017-12849 There is a carry propagating bug in the x86_64 Montgomery squaring procedure in OpenSSL 1.0.2 before 1.0.2k and 1.1.0 before 1.1.0d. No EC algorithms are affected. Analysis suggests that attacks against RSA and DSA as a result of this defect would be very difficult to perform and are not believed likely. Attacks against DH are considered just feasible (although very difficult) because most of the work necessary to deduce information about a private key may be performed offline. The amount of resources required for such an attack would be very significant and likely only accessible to a limited number of attackers. An attacker would additionally need online access to an unpatched system using the target private key in a scenario with persistent DH parameters and a private key that is shared between multiple clients. For example this can occur by default in OpenSSL DHE based SSL/TLS ciphersuites. Note: This issue is very similar to CVE-2015-3193 but must be treated as a separate problem.
Ubuntu USN Ubuntu USN USN-3181-1 OpenSSL vulnerabilities
History

No history.

Weaknesses

Sources

Status
PUBLISHED
Assigner
openssl
Published
Updated
Sep 16, 2024, 10:08 PM
Reserved
Dec 16, 2016, 12:00 AM
Status
Modified
Published
May 4, 2017, 7:29 PM
Modified
Jun 17, 2026, 1:18 AM
Severity
Moderate
Public date
Jan 26, 2017, 12:00 AM