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Bug 572566 (CVE-2016-1567) - <net-misc/chrony-2.2.1 Impersonation between authenticated peers (CVE-2016-1567)
Summary: <net-misc/chrony-2.2.1 Impersonation between authenticated peers (CVE-2016-1567)
Alias: CVE-2016-1567
Product: Gentoo Security
Classification: Unclassified
Component: Vulnerabilities (show other bugs)
Hardware: All Linux
: Normal normal (vote)
Assignee: Gentoo Security
Whiteboard: B3 [noglsa cve]
Depends on:
Reported: 2016-01-22 04:42 UTC by Jeroen Roovers (RETIRED)
Modified: 2016-06-21 09:52 UTC (History)
0 users

See Also:
Package list:
Runtime testing required: ---


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Description Jeroen Roovers (RETIRED) gentoo-dev 2016-01-22 04:42:11 UTC

20 Jan 2016: chrony-2.2.1 and chrony-1.31.2 released

Security fixes
Restrict authentication of NTP server/peer to specified key (CVE-2016-1567)

CVE-2016-1567: Impersonation between authenticated peers
When a server/peer was specified with a key number to enable authentication with a symmetric key, packets received from the server/peer were accepted if they were authenticated with any of the keys contained in the key file and not just the specified key.

This allowed an attacker who knew one key of a client/peer to modify packets from its servers/peers that were authenticated with other keys in a man-in-the-middle (MITM) attack. For example, in a network where each NTP association had a separate key and all hosts had only keys they needed, a client of a server could not attack other clients of the server, but it could attack the server and also attack its own clients (i.e. modify packets from other servers).

To not allow the server/peer to be authenticated with other keys, the authentication test was extended to check if the key ID in the received packet is equal to the configured key number. As a consequence, it’s no longer possible to authenticate two peers to each other with two different keys, both peers have to be configured to use the same key.

This issue was discovered by Matt Street of Cisco ASIG.

Comment 1 Jeroen Roovers (RETIRED) gentoo-dev 2016-01-22 04:45:22 UTC
Arch teams, please test and mark stable:
Targeted stable KEYWORDS : amd64 hppa ppc ppc64 sparc x86
Comment 2 Jeroen Roovers (RETIRED) gentoo-dev 2016-01-22 08:59:05 UTC
Stable for HPPA PPC64.
Comment 3 Agostino Sarubbo gentoo-dev 2016-01-24 17:35:55 UTC
amd64 stable
Comment 4 Agostino Sarubbo gentoo-dev 2016-03-15 16:42:12 UTC
x86 stable
Comment 5 Agostino Sarubbo gentoo-dev 2016-03-16 12:05:44 UTC
ppc stable
Comment 6 Agostino Sarubbo gentoo-dev 2016-03-19 11:38:28 UTC
sparc stable.

Maintainer(s), please cleanup.
Security, please vote.
Comment 7 GLSAMaker/CVETool Bot gentoo-dev 2016-06-21 09:46:29 UTC
CVE-2016-1567 (
  chrony before 1.31.2 and 2.x before 2.2.1 do not verify peer associations of
  symmetric keys when authenticating packets, which might allow remote
  attackers to conduct impersonation attacks via an arbitrary trusted key, aka
  a "skeleton key."
Comment 8 Aaron Bauman Gentoo Infrastructure gentoo-dev Security 2016-06-21 09:52:07 UTC
GLSA Vote: No