Bug 1188491 (CVE-2020-36423) - VUL-0: CVE-2020-36423: mbedtls: remote attacker can recover plaintext because a certain Lucky 13 countermeasure doesn't properly work
Summary: VUL-0: CVE-2020-36423: mbedtls: remote attacker can recover plaintext because...
Status: RESOLVED FIXED
Alias: CVE-2020-36423
Product: openSUSE Distribution
Classification: openSUSE
Component: Basesystem (show other bugs)
Version: Leap 15.2
Hardware: Other Other
: P3 - Medium : Normal (vote)
Target Milestone: ---
Assignee: Security Team bot
QA Contact: Security Team bot
URL: https://smash.suse.de/issue/304567/
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2021-07-20 06:02 UTC by Alexander Bergmann
Modified: 2021-08-06 09:25 UTC (History)
1 user (show)

See Also:
Found By: Security Response Team
Services Priority:
Business Priority:
Blocker: ---
Marketing QA Status: ---
IT Deployment: ---


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Description Alexander Bergmann 2021-07-20 06:02:55 UTC
CVE-2020-36423

An issue was discovered in Arm Mbed TLS before 2.23.0. A remote attacker can
recover plaintext because a certain Lucky 13 countermeasure doesn't properly
consider the case of a hardware accelerator.

References:
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2020-36423
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-36423
https://github.com/ARMmbed/mbedtls/releases/tag/v2.23.0
https://github.com/ARMmbed/mbedtls/releases/tag/v2.16.7
https://bugs.gentoo.org/730752
Comment 1 Pedro Monreal Gonzalez 2021-08-05 09:52:02 UTC
CVE-2020-36423:

Fix issue in Lucky 13 counter-measure that could make it ineffective when hardware accelerators were used (using one of the MBEDTLS_SHAxxx_ALT macros). This would cause the original Lucky 13 attack to be possible in those configurations, allowing an active network attacker to recover plaintext after repeated timing measurements under some conditions. Reported and fix suggested by Luc Perneel in #3246.

See also: https://github.com/ARMmbed/mbedtls/issues/3246
Comment 2 Pedro Monreal Gonzalez 2021-08-05 10:17:16 UTC
We have a fixed version 2.16.9 in openSUSE:Leap:15.2:Update
Updated to 2.27.0 in Factory: https://build.opensuse.org/request/show/907287

I think nothing else to be done.
Comment 4 Marcus Meissner 2021-08-06 09:25:45 UTC
done