Bug 1849743

Summary:	botan: CBC padding operations were not constant time and as a result would leak the length of the plaintext values which were being padded
Product:	[Other] Security Response	Reporter:	Michael Kaplan <mkaplan>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED UPSTREAM	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	bkircher, thomas.moschny
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	botan 2.14.0	Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2020-06-22 23:20:28 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	1849744, 1849745, 1849746, 1849747
Bug Blocks:

Description Michael Kaplan 2020-06-22 17:28:19 UTC

The CBC padding operations were not constant time and as a result would leak the length of the plaintext values which were being padded to an attacker running a side channel attack via shared resources such as cache or branch predictor. No information about the contents was leaked, but the length alone might be used to make inferences about the contents. This issue affects TLS CBC ciphersuites as well as CBC encryption using PKCS7 or other similar padding mechanisms. In all cases, the unpadding operations were already constant time and are not affected. 

Fixed in 2.14.0, all prior versions affected.

Comment 1 Michael Kaplan 2020-06-22 17:28:45 UTC

Created botan tracking bugs for this issue:

Affects: epel-all [bug 1849747]
Affects: fedora-all [bug 1849744]


Created botan2 tracking bugs for this issue:

Affects: epel-8 [bug 1849746]
Affects: fedora-all [bug 1849745]

Comment 2 Product Security DevOps Team 2020-06-22 23:20:28 UTC

This CVE Bugzilla entry is for community support informational purposes only as it does not affect a package in a commercially supported Red Hat product. Refer to the dependent bugs for status of those individual community products.