NTP is a protocol designed to synchronize the clocks of
computers over a network. The NTP Project produces a reference implementation
of the NTP protocol and implementation documentation through a largely
volunteer effort. NTP uses a hierarchical, semi-layered system of time sources.
Each level of this hierarchy is termed a "stratum" and is assigned a
number starting with zero at the top.
The NTP Project conducts Research and Development in NTP and
produces the Official Reference Implementation of NTP along with the
Implementation Documentation. A few weeks ago, ntp-4.2.8p4 was released which
fixed multiple vulnerabilities.
- "NTP Daemon Arbitrary File Overwrite", which addresses CVE-2015-7703
Description: If ntpd is
configured to allow for remote configuration, and if the (possibly spoofed)
source IP address is allowed to send remote configuration requests, and if the
attacker knows the remote configuration password, it's possible for an attacker
to use the "pidfile" or "driftfile" directives to
potentially overwrite other files.
- "NTP Daemon Assertion Failure DoS", which addresses CVE-2015-7855
Description: If ntpd is fed a
crafted mode 6 or mode 7 packet containing an unusually long data value where a
network address is expected, the decodenetnum() function will abort with an
assertion failure instead of simply returning a failure condition.
- "NTP Daemon
Crypto-NAK Authentication Bypass 1" and
"NTP Daemon Crypto-NAK Authentication Bypass 2", which address CVE-2015-7871
Description: Crypto-NAK packets
can be used to cause ntpd to accept time from unauthenticated ephemeral
symmetric peers by bypassing the authentication required to mobilize peer
associations. This vulnerability appears to have been introduced in
ntp-4.2.5p186 when the code handling mobilization of new passive symmetric
associations was refactored.
The most
critical one in the above list is the crypto-NAK bug. Administrators are urged
to upgrade ntpd to the latest version to protect their servers.
Source:
Dell SonicWall Security Center
Have a
good time.
(Be knowledgeable, pass it on then)
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