Bug 1007806

Summary: VUL-1: CVE-2016-0702: libressl: Side channel attack on modular exponentiation "CacheBleed"
Product: [Novell Products] SUSE Security Incidents Reporter: Andreas Stieger <astieger>
Component: IncidentsAssignee: Jan Engelhardt <jengelh>
Status: RESOLVED FIXED QA Contact: Security Team bot <security-team>
Severity: Minor    
Priority: P4 - Low CC: jengelh
Version: unspecified   
Target Milestone: ---   
Hardware: Other   
OS: openSUSE 42.1   
Whiteboard:
Found By: Security Response Team Services Priority:
Business Priority: Blocker: ---
Marketing QA Status: --- IT Deployment: ---
Bug Depends on:    
Bug Blocks: 968050    

Description Andreas Stieger 2016-10-31 16:50:17 UTC 
From OpenSSL Advisory:

Side channel attack on modular exponentiation (CVE-2016-0702)
=============================================================

Severity: Low

A side-channel attack was found which makes use of cache-bank conflicts on the
Intel Sandy-Bridge microarchitecture which could lead to the recovery of RSA
keys.  The ability to exploit this issue is limited as it relies on an attacker
who has control of code in a thread running on the same hyper-threaded core as
the victim thread which is performing decryptions.

===

Fixed in LibreSSL 2.5.0:
From https://ftp.openbsd.org/pub/OpenBSD/LibreSSL/libressl-2.5.0-relnotes.txt

  * Added constant-time updates to address CVE-2016-0702

Fix (roughly):
https://github.com/libressl-portable/openbsd/commit/6c06cb1481dfc86fc402c8fdc1643a75c121d8b7
https://github.com/libressl-portable/openbsd/commit/66673270190461046d0380e4ea40c47e9a74a4a6
https://github.com/libressl-portable/openbsd/commit/37427e5dd4a67015e881bbdd494dbed4590b29d9

openSUSE:13.2:Update/libressl      2.2.7
openSUSE:Leap:42.1:Update/libressl 2.3.0
openSUSE:Leap:42.2:Update/libressl 2.3.4

Jan, this attack is somewhat theoretical, we won't push for an update. What do you think?
Comment 1 Swamp Workflow Management 2016-10-31 23:02:25 UTC 
bugbot adjusting priority
Comment 2 Bernhard Wiedemann 2017-04-28 12:01:38 UTC 
This is an autogenerated message for OBS integration:
This bug (1007806) was mentioned in
https://build.opensuse.org/request/show/491819 42.1 / libressl
Comment 3 Andreas Stieger 2017-05-26 19:20:21 UTC 
done