Bug 1889988 (CVE-2020-25659) - CVE-2020-25659 python-cryptography: Bleichenbacher timing oracle attack against RSA decryption
Summary: CVE-2020-25659 python-cryptography: Bleichenbacher timing oracle attack again...
Keywords:
Status: CLOSED ERRATA
Alias: CVE-2020-25659
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: 1873581 1927616 1927617 1927618 1927619 1928183 1929131 1929461 1929462 1935588 1935589 1935590 1969515 2153471
Blocks: 1889989
TreeView+ depends on / blocked
 
Reported: 2020-10-21 07:29 UTC by Huzaifa S. Sidhpurwala
Modified: 2024-04-11 13:54 UTC (History)
45 users (show)

Fixed In Version: python-cryptography 3.2
Clone Of:
Environment:
Last Closed: 2021-05-18 20:36:49 UTC
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2021:3254 0 None None None 2021-08-24 08:09:00 UTC

Description Huzaifa S. Sidhpurwala 2020-10-21 07:29:56 UTC 
python-cryptography is vulnerable to Bleichenbacher timing attacks in the RSA decryption API, via timed processing of valid PKCS#1 v1.5 ciphertext.
Comment 3 Todd Cullum 2021-01-05 20:14:27 UTC 
Upstream commit: https://github.com/pyca/cryptography/pull/5507/commits/ce1bef6f1ee06ac497ca0c837fbd1c7ef6c2472b
Comment 4 Huzaifa S. Sidhpurwala 2021-02-11 07:03:53 UTC 
Acknowledgments:

Name: Hubert Kario (Red Hat)
Comment 6 Christian Heimes 2021-02-11 07:37:38 UTC 
The upstream patch in python-cryptography >= 3.2 is only a partial mitigation against Bleichenbacher attacks.

Quote from upstream changelog:

    **SECURITY ISSUE:** Attempted to make RSA PKCS#1v1.5 decryption more constant
    time, to protect against Bleichenbacher vulnerabilities. Due to limitations
    imposed by our API, we cannot completely mitigate this vulnerability and a
    future release will contain a new API which is designed to be resilient to
    these for contexts where it is required. Credit to **Hubert Kario** for
    reporting the issue. *CVE-2020-25659*

RHEL 8.4 and newer have a recent version of python-cryptography with partial mitigation. RHBZ #1873581 is the rebase ticket for update to 3.2.1.
Comment 9 Yadnyawalk Tale 2021-02-12 15:31:22 UTC 
CloudForms stopped shipping python-cryptography 5.11 (5.0) onward. Support for 5.10 (4.7) is EOL from February 7, 2021. Please refer CloudForms Lifecycle page for more information: https://access.redhat.com/support/policy/updates/cloudforms
Comment 10 Summer Long 2021-02-16 05:43:59 UTC 
External References:

https://cryptography.io/en/latest/changelog.html#v3-2
Comment 13 Summer Long 2021-02-17 00:48:52 UTC 
Created python-cryptography tracking bugs for this issue:

Affects: openstack-rdo [bug 1929462]
Comment 16 Summer Long 2021-03-15 01:21:39 UTC 
Statement:

In Red Hat OpenStack Platform, because the flaw has a lower impact and the fix would require a substantial amount of development, no update will be provided at this time for the RHOSP python-cryptography package.
Comment 25 errata-xmlrpc 2021-05-18 13:40:00 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2021:1608 https://access.redhat.com/errata/RHSA-2021:1608
Comment 26 Product Security DevOps Team 2021-05-18 20:36:49 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-2020-25659
Comment 27 errata-xmlrpc 2021-06-03 10:24:19 UTC 
This issue has been addressed in the following products:

  Red Hat Virtualization 4 for Red Hat Enterprise Linux 8

Via RHSA-2021:2239 https://access.redhat.com/errata/RHSA-2021:2239
Comment 28 errata-xmlrpc 2021-08-24 08:08:58 UTC 
This issue has been addressed in the following products:

  Red Hat Software Collections for Red Hat Enterprise Linux 7
  Red Hat Software Collections for Red Hat Enterprise Linux 7.7 EUS

Via RHSA-2021:3254 https://access.redhat.com/errata/RHSA-2021:3254
Note You need to log in before you can comment on or make changes to this bug.