Bug 908234 (CVE-2013-1620)

Summary: CVE-2013-1620 nss: TLS CBC padding timing attack
Product: [Other] Security Response Reporter: Huzaifa S. Sidhpurwala <huzaifas>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED ERRATA QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: emaldona, kdudka, kengert, mjc
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard: impact=moderate,public=20130204,reported=20130204,source=internet,cvss2=5.1/AV:N/AC:H/Au:N/C:P/I:P/A:P,rhel-5/nss=affected,rhel-6/nss=affected,fedora-all/nss=affected
Fixed In Version: nss 3.14.3 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2016-06-10 17:23:17 EDT Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---
Bug Depends On: 908257, 918870, 918872, 918874, 918875    
Bug Blocks: 907592    

Description Huzaifa S. Sidhpurwala 2013-02-06 03:44:35 EST
A flaw in how TLS/DTLS, when CBC-mode encryption is used, communicates was reported.  This vulnerability can allow for a Man-in-the-Middle attacker to recover plaintext from a TLS/DTLS connection, when CBC-mode encryption is used.

This flaw is in the TLS specification, and not a bug in a specific implementation (as such, it affects nearly all implementations).  As such, it affects all TLS and DTLS implementations that are compliant with TLS 1.1 or 1.2, or with DTLS 1.0 or 1.2.  It also applies to implementations of SSL 3.0 and TLS 1.0 that incorporate countermeasures to deal with previous padding oracle attacks.  All TLS/DTLS ciphersuites that include CBC-mode encryption are potentially vulnerable.

To perform a successful attack, when TLS is used, a large number of TLS sessions are required (target plaintext must be sent repeatedly in the same position in the plaintext stream across the sessions).  For DTLS, a successful attack can be carried out in a single session.  The attacker must also be located close to the machine being attacked.

Further details are noted in the paper:


Currently Mozilla is working on final NSS fixes:


External References:

Comment 1 Huzaifa S. Sidhpurwala 2013-02-06 04:31:31 EST
Created nss tracking bugs for this issue

Affects: fedora-all [bug 908257]
Comment 4 Tomas Hoger 2013-02-28 02:15:05 EST
Fixed upstream in nss and nss-softoken 3.14.3:

Comment 6 errata-xmlrpc 2013-08-05 11:54:35 EDT
This issue has been addressed in following products:

  Red Hat Enterprise Linux 5

Via RHSA-2013:1135 https://rhn.redhat.com/errata/RHSA-2013-1135.html
Comment 7 errata-xmlrpc 2013-08-07 13:50:20 EDT
This issue has been addressed in following products:

  Red Hat Enterprise Linux 6

Via RHSA-2013:1144 https://rhn.redhat.com/errata/RHSA-2013-1144.html
Comment 8 errata-xmlrpc 2013-08-27 14:54:21 EDT
This issue has been addressed in following products:

  RHEV-H and Agents for RHEL-6

Via RHSA-2013:1181 https://rhn.redhat.com/errata/RHSA-2013-1181.html