Bug 1826187 (CVE-2020-6829) - CVE-2020-6829 nss: Side channel attack on ECDSA signature generation
Summary: CVE-2020-6829 nss: Side channel attack on ECDSA signature generation
Keywords:
Status: CLOSED ERRATA
Alias: CVE-2020-6829
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 1862359 1862387 1862388 1905151
Blocks: 1826178
TreeView+ depends on / blocked
 
Reported: 2020-04-21 08:16 UTC by Marian Rehak
Modified: 2021-02-16 20:14 UTC (History)
16 users (show)

Fixed In Version: nss 3.55
Doc Type: If docs needed, set a value
Doc Text:
A flaw was found in nss. Using the EM side-channel, it is possible to extract the position of zero and non-zero wNAF digits while nss-certutil tool performs scalar multiplication during the ECDSA signature generation, 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:
Environment:
Last Closed: 2020-09-30 03:57:06 UTC


Attachments (Terms of Use)


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

Description Marian Rehak 2020-04-21 08:16:57 UTC
Using the EM side-channel, it is possible to extract the position of zero and non-zero wNAF digits while nss-certutil tool performs scalar multiplication during the ECDSA signature generation, leaking partial information about the ECDSA nonce. Given a small number of ECDSA signatures, this information can be used to steal the private key.

Comment 1 Mark Cooper 2020-04-22 05:54:01 UTC
OpenShift 4.x only packages nss-altfiles and has been confirmed to *not* share any of the vulnerable signature code:
    - nss-altfiles only reads information from files in the same format as /etc/passwd and /etc/group.

Comment 2 Huzaifa S. Sidhpurwala 2020-05-20 03:39:24 UTC
Acknowledgments:

Name: the Mozilla Project
Upstream: Cesar Pereida (Network and Information Security Group (NISEC), Billy Bob Brumley (Network and Information Security Group (NISEC), Yuval Yarom (Network and Information Security Group (NISEC), Nicola Tuveri (Network and Information Security Group (NISEC)

Comment 4 Huzaifa S. Sidhpurwala 2020-07-31 08:09:27 UTC
External References:

https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NSS/NSS_3.55_release_notes

Comment 5 Huzaifa S. Sidhpurwala 2020-07-31 08:13:21 UTC
Created nss tracking bugs for this issue:

Affects: fedora-all [bug 1862359]

Comment 6 Huzaifa S. Sidhpurwala 2020-07-31 10:02:41 UTC
Statement:

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 7 Huzaifa S. Sidhpurwala 2020-07-31 10:02:47 UTC
Mitigation:

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 10 errata-xmlrpc 2020-09-29 20:58:26 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 11 Product Security DevOps Team 2020-09-30 03:57:06 UTC
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):

https://access.redhat.com/security/cve/cve-2020-6829

Comment 12 errata-xmlrpc 2021-02-16 14:26:12 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


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