Bug 1851294 (CVE-2020-12401) - CVE-2020-12401 nss: ECDSA timing attack mitigation bypass
Summary: CVE-2020-12401 nss: ECDSA timing attack mitigation bypass
Keywords:
Status: CLOSED ERRATA
Alias: CVE-2020-12401
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: 1862389 1862390 1862391 1862393 1905152
Blocks: 1826178
TreeView+ depends on / blocked
 
Reported: 2020-06-26 04:17 UTC by Huzaifa S. Sidhpurwala
Modified: 2022-08-26 09:29 UTC (History)
9 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 03:57:14 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 20:58:41 UTC

Description Huzaifa S. Sidhpurwala 2020-06-26 04:17:32 UTC
A timing attacker against ECDSA signature generation is able to obtain information from the secret nonce measuring the time an ECDSA signature generation takes. Current NSS code path has a countermeasure to prevent this know attack since 2011. However it was found that said countermeasure could be completely bypassed. Different flaw from CVE-2020-6829.

Comment 1 Huzaifa S. Sidhpurwala 2020-06-26 04:17:36 UTC
Acknowledgments:

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

Comment 3 Huzaifa S. Sidhpurwala 2020-07-31 08:11:03 UTC
External References:

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

Comment 4 Huzaifa S. Sidhpurwala 2020-07-31 10:08:33 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 5 Huzaifa S. Sidhpurwala 2020-07-31 10:08:38 UTC
Mitigation:

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 10:26:31 UTC
Created nss tracking bugs for this issue:

Affects: fedora-all [bug 1862393]

Comment 10 errata-xmlrpc 2020-09-29 20:58:38 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 03:57:14 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-2020-12401

Comment 12 Vincent Latombe 2022-06-07 14:28:21 UTC
How come this has been addressed for RHEL 7 but not RHEL 8 ? The CVE page still indicates RHEL 8 is 'affected.

Comment 13 Mauro Matteo Cascella 2022-08-26 09:29:59 UTC
The CVE page is now updated, showing that nss in RHEL-8 was fixed via RHSA-2021:0538.


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