Bug 1853983 (CVE-2020-12400) - CVE-2020-12400 nss: P-384 and P-521 implementation uses a side-channel vulnerable modular inversion function
Summary: CVE-2020-12400 nss: P-384 and P-521 implementation uses a side-channel vulner...
Alias: CVE-2020-12400
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
Depends On: 1862356 1862391 1862392 1905152
Blocks: 1826178
TreeView+ depends on / blocked
Reported: 2020-07-06 03:36 UTC by Huzaifa S. Sidhpurwala
Modified: 2021-06-15 13:08 UTC (History)
8 users (show)

Fixed In Version: nss 3.55
Doc Type: Bug Fix
Doc Text:
A side-channel flaw was found in NSS, in the way P-384 and P-521 curves are used in the generation of EDSA signatures, leaking partial information about the ECDSA nonce. Given a small number of ECDSA signatures, this information can be used to steal the private key. The highest threat from this vulnerability is to data confidentiality.
Clone Of:
Last Closed: 2020-09-30 03:57:17 UTC

Attachments (Terms of Use)

System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2020:4076 0 None None None 2020-09-29 20:58:43 UTC
Red Hat Product Errata RHSA-2021:0538 0 None None None 2021-02-16 14:26:16 UTC

Description Huzaifa S. Sidhpurwala 2020-07-06 03:36:17 UTC
As per the researcher:

During our analysis to several cryptographic libraries we focused on NIST curve P-256 code paths and have found that your library is potentially vulnerable because the projective to affine coordinates conversion uses a side-channel vulnerable modular inversion function.

Comment 1 Huzaifa S. Sidhpurwala 2020-07-06 03:36:22 UTC

Name: the Mozilla Project
Upstream: Cesar Pereida Garcia and the Network and Information Security Group (NISEC)

Comment 3 Huzaifa S. Sidhpurwala 2020-07-31 08:04:06 UTC
External References:


Comment 4 Huzaifa S. Sidhpurwala 2020-07-31 08:06:13 UTC
Created nss tracking bugs for this issue:

Affects: fedora-all [bug 1862356]

Comment 5 Huzaifa S. Sidhpurwala 2020-07-31 10:16:55 UTC

This is a side channel attack which can used to exact pirate keys when ECDSA signatures are being generated. This attack is only feasible when the attacker is local to the machine or in certain cross-VM scenarios where the signature is being generated. Attacks over the network or via the internet are not feasible.

Comment 6 Huzaifa S. Sidhpurwala 2020-07-31 10:16:57 UTC

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

Comment 9 errata-xmlrpc 2020-09-29 20:58:40 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2020:4076 https://access.redhat.com/errata/RHSA-2020:4076

Comment 10 Product Security DevOps Team 2020-09-30 03:57:17 UTC
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):


Comment 11 errata-xmlrpc 2021-02-16 14:26:15 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2021:0538 https://access.redhat.com/errata/RHSA-2021:0538

Note You need to log in before you can comment on or make changes to this bug.