[arch-security] [ASA-201504-9] chrony: denial of service

Christian Rebischke chris.rebischke at gmail.com
Wed Apr 8 17:35:41 UTC 2015

Arch Linux Security Advisory ASA-201504-9

Severity: Medium
Date    : 2015-04-08
CVE-ID  : CVE-2015-1853
Package : chrony
Type    : denial of service
Remote  : Yes
Link    : https://wiki.archlinux.org/index.php/CVE


The package chrony before version 1.31-2 is vulnerable to denial of service


Upgrade to 1.31-2.

# pacman -Syu "chrony>=1.31-2"

The problem has been fixed upstream.




CVE-2015-1853 (denial of service):
This issue is similiar to the "ntp CVE-2015-1799"-issue.
An attacker knowing that NTP hosts A and B are peering with each other
(symmetric association) can send a packet to host A with source address of B
which will set the NTP state variables on A to the values sent by the attacker.
Host A will then send on its next poll to B a packet with originate timestamp
that doesn't match the transmit timestamp of B and the packet will be dropped.
If the attacker does this periodically for both hosts, they won't be able to
synchronize to each other. This is a known denial-of-service attack


CVE-2015-1853 (denial of service):

An attacker could stop the synchronizing process of chrony.



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