Bug 1889972 (CVE-2020-25658) - CVE-2020-25658 python-rsa: bleichenbacher timing oracle attack against RSA decryption
Summary: CVE-2020-25658 python-rsa: bleichenbacher timing oracle attack against RSA de...
Alias: CVE-2020-25658
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
Depends On: 1895779 1895780 1897967 1897968 1898967 1899504 1902905 1910656
Blocks: 1889973
TreeView+ depends on / blocked
Reported: 2020-10-21 06:44 UTC by Huzaifa S. Sidhpurwala
Modified: 2022-05-05 07:53 UTC (History)
34 users (show)

See Also:
Fixed In Version:
Doc Type: If docs needed, set a value
Doc Text:
A flaw was found in python-rsa, where it is vulnerable to Bleichenbacher timing attacks. This flaw allows an attacker, via the RSA decryption API, to decrypt parts of the ciphertext encrypted with RSA. The highest threat from this vulnerability is to confidentiality.
Clone Of:
Last Closed: 2021-02-24 19:02:04 UTC

Attachments (Terms of Use)

System ID Private Priority Status Summary Last Updated
Github sybrenstuvel python-rsa issues 165 0 None closed CVE-2020-25658 - Bleichenbacher-style timing oracle in PKCS#1 v1.5 decryption code 2021-02-02 20:48:02 UTC
Red Hat Product Errata RHSA-2020:5634 0 None None None 2021-02-24 14:42:09 UTC
Red Hat Product Errata RHSA-2021:0637 0 None None None 2021-03-03 12:26:59 UTC
Red Hat Product Errata RHSA-2022:1716 0 None None None 2022-05-05 07:53:12 UTC

Description Huzaifa S. Sidhpurwala 2020-10-21 06:44:47 UTC
Python-rsa is vulnerable to Bleichenbacher timing attacks in the RSA decryption API, via timed processing of valid PKCS#1 v1.5 ciphertext.

Comment 5 Huzaifa S. Sidhpurwala 2020-11-09 04:13:56 UTC
Created python-rsa tracking bugs for this issue:

Affects: epel-all [bug 1895780]
Affects: fedora-all [bug 1895779]

Comment 7 Hubert Kario 2020-11-09 14:57:59 UTC
Fix doc text: the vulnerability *is* present, it is *not* fixed—there are no patches proposed to fix it.

I haven't looked at the old code, but I don't expect any old versions to be secure, the issue at least partially stems from the fact that the API raises an exception in case of malformed plaintext, so all versions that can raise an exception in decryption API are vulnerable.

Comment 10 Hubert Kario 2020-11-10 11:23:17 UTC
It looks like all versions since 2.1 (inclusive) are vulnerable, versions before 2.1 don't provide RSA decryption API: https://github.com/sybrenstuvel/python-rsa/commit/714324a9a34f0958704e5064251a1f00ed37a372

Comment 13 Jason Shepherd 2020-11-18 01:21:55 UTC

Comment 18 Summer Long 2020-12-10 02:29:12 UTC

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-rsa package.

Comment 19 Huzaifa S. Sidhpurwala 2020-12-24 08:43:27 UTC
External References:


Comment 21 Huzaifa S. Sidhpurwala 2021-02-11 07:03:44 UTC

Name: Hubert Kario (Red Hat)

Comment 22 errata-xmlrpc 2021-02-24 14:42:05 UTC
This issue has been addressed in the following products:

  Red Hat OpenShift Container Platform 4.7

Via RHSA-2020:5634 https://access.redhat.com/errata/RHSA-2020:5634

Comment 23 Product Security DevOps Team 2021-02-24 19:02:04 UTC
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):


Comment 24 errata-xmlrpc 2021-03-03 12:26:52 UTC
This issue has been addressed in the following products:

  Red Hat OpenShift Container Platform 3.11

Via RHSA-2021:0637 https://access.redhat.com/errata/RHSA-2021:0637

Comment 25 errata-xmlrpc 2022-05-05 07:53:10 UTC
This issue has been addressed in the following products:

  Red Hat Ceph Storage 4.3

Via RHSA-2022:1716 https://access.redhat.com/errata/RHSA-2022:1716

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