The Google security team discovered several vulnerabilities in current NTP implementations, one of which can lead to arbitrary code execution [1][2]. NTP servers prior to version 4.2.8 are affected. There are some rumors about active exploitation of at least some of the vulnerabilities Google discovered. Make sure to patch all publicly reachable NTP implementations as fast as possible. Mitigating Circumstances: Try to block inbound connections to ntp servers who do not have to be publicly reachable. However, be aware that simple statefull firewalls may not track UDP connections correctly and will allow access to internal NTP servers from any external IP if the NTP server recently established an outbound connection. ntpd typically does not have to run as root. Most Unix/Linux versions will configure NTP using a lower privileged users. According to the advisory at ntp.org, you can also:
A few Ubuntu and CentOS systems I tested, as well as OS X systems, do not seem to use autokey. [1] http://www.kb.cert.org/vuls/id/852879
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Johannes 4504 Posts ISC Handler Dec 20th 2014 |
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Dec 20th 2014 7 years ago |
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Did they ever fix the silent crash bug in 4.2.7? I'm still on 4.2.6. Good thing I stopped letting the public access my NTP server... The 200,000 connection packet floods were getting excessive.
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Anonymous |
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Dec 20th 2014 7 years ago |
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