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Diffstat (limited to 'contrib/ntp/NEWS')
| -rw-r--r-- | contrib/ntp/NEWS | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/contrib/ntp/NEWS b/contrib/ntp/NEWS index d33f059..a425a9a 100644 --- a/contrib/ntp/NEWS +++ b/contrib/ntp/NEWS @@ -1,4 +1,145 @@ --- +NTP 4.2.8p2 (Harlan Stenn <stenn@ntp.org>, 2015/04/xx) + +Focus: Security and Bug fixes, enhancements. + +Severity: MEDIUM + +In addition to bug fixes and enhancements, this release fixes the +following medium-severity vulnerabilities involving private key +authentication: + +* [Sec 2779] ntpd accepts unauthenticated packets with symmetric key crypto. + + References: Sec 2779 / CVE-2015-1798 / VU#374268 + Affects: All NTP4 releases starting with ntp-4.2.5p99 up to but not + including ntp-4.2.8p2 where the installation uses symmetric keys + to authenticate remote associations. + CVSS: (AV:A/AC:M/Au:N/C:P/I:P/A:P) Base Score: 5.4 + Date Resolved: Stable (4.2.8p2) 07 Apr 2015 + Summary: When ntpd is configured to use a symmetric key to authenticate + a remote NTP server/peer, it checks if the NTP message + authentication code (MAC) in received packets is valid, but not if + there actually is any MAC included. Packets without a MAC are + accepted as if they had a valid MAC. This allows a MITM attacker to + send false packets that are accepted by the client/peer without + having to know the symmetric key. The attacker needs to know the + transmit timestamp of the client to match it in the forged reply + and the false reply needs to reach the client before the genuine + reply from the server. The attacker doesn't necessarily need to be + relaying the packets between the client and the server. + + Authentication using autokey doesn't have this problem as there is + a check that requires the key ID to be larger than NTP_MAXKEY, + which fails for packets without a MAC. + Mitigation: + Upgrade to 4.2.8p2, or later, from the NTP Project Download Page + or the NTP Public Services Project Download Page + Configure ntpd with enough time sources and monitor it properly. + Credit: This issue was discovered by Miroslav Lichvar, of Red Hat. + +* [Sec 2781] Authentication doesn't protect symmetric associations against + DoS attacks. + + References: Sec 2781 / CVE-2015-1799 / VU#374268 + Affects: All NTP releases starting with at least xntp3.3wy up to but + not including ntp-4.2.8p2 where the installation uses symmetric + key authentication. + CVSS: (AV:A/AC:M/Au:N/C:P/I:P/A:P) Base Score: 5.4 + Note: the CVSS base Score for this issue could be 4.3 or lower, and + it could be higher than 5.4. + Date Resolved: Stable (4.2.8p2) 07 Apr 2015 + Summary: 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, described at + https://www.eecis.udel.edu/~mills/onwire.html . + + According to the document the NTP authentication is supposed to + protect symmetric associations against this attack, but that + doesn't seem to be the case. The state variables are updated even + when authentication fails and the peers are sending packets with + originate timestamps that don't match the transmit timestamps on + the receiving side. + + This seems to be a very old problem, dating back to at least + xntp3.3wy. It's also in the NTPv3 (RFC 1305) and NTPv4 (RFC 5905) + specifications, so other NTP implementations with support for + symmetric associations and authentication may be vulnerable too. + An update to the NTP RFC to correct this error is in-process. + Mitigation: + Upgrade to 4.2.8p2, or later, from the NTP Project Download Page + or the NTP Public Services Project Download Page + Note that for users of autokey, this specific style of MITM attack + is simply a long-known potential problem. + Configure ntpd with appropriate time sources and monitor ntpd. + Alert your staff if problems are detected. + Credit: This issue was discovered by Miroslav Lichvar, of Red Hat. + +* New script: update-leap +The update-leap script will verify and if necessary, update the +leap-second definition file. +It requires the following commands in order to work: + + wget logger tr sed shasum + +Some may choose to run this from cron. It needs more portability testing. + +Bug Fixes and Improvements: + +* [Bug 1787] DCF77's formerly "antenna" bit is "call bit" since 2003. +* [Bug 1960] setsockopt IPV6_MULTICAST_IF: Invalid argument. +* [Bug 2346] "graceful termination" signals do not do peer cleanup. +* [Bug 2728] See if C99-style structure initialization works. +* [Bug 2747] Upgrade libevent to 2.1.5-beta. +* [Bug 2749] ntp/lib/NTP/Util.pm needs update for ntpq -w, IPv6, .POOL. . +* [Bug 2751] jitter.h has stale copies of l_fp macros. +* [Bug 2756] ntpd hangs in startup with gcc 3.3.5 on ARM. +* [Bug 2757] Quiet compiler warnings. +* [Bug 2759] Expose nonvolatile/clk_wander_threshold to ntpq. +* [Bug 2763] Allow different thresholds for forward and backward steps. +* [Bug 2766] ntp-keygen output files should not be world-readable. +* [Bug 2767] ntp-keygen -M should symlink to ntp.keys. +* [Bug 2771] nonvolatile value is documented in wrong units. +* [Bug 2773] Early leap announcement from Palisade/Thunderbolt +* [Bug 2774] Unreasonably verbose printout - leap pending/warning +* [Bug 2775] ntp-keygen.c fails to compile under Windows. +* [Bug 2777] Fixed loops and decoding of Meinberg GPS satellite info. + Removed non-ASCII characters from some copyright comments. + Removed trailing whitespace. + Updated definitions for Meinberg clocks from current Meinberg header files. + Now use C99 fixed-width types and avoid non-ASCII characters in comments. + Account for updated definitions pulled from Meinberg header files. + Updated comments on Meinberg GPS receivers which are not only called GPS16x. + Replaced some constant numbers by defines from ntp_calendar.h + Modified creation of parse-specific variables for Meinberg devices + in gps16x_message(). + Reworked mk_utcinfo() to avoid printing of ambiguous leap second dates. + Modified mbg_tm_str() which now expexts an additional parameter controlling + if the time status shall be printed. +* [Sec 2779] ntpd accepts unauthenticated packets with symmetric key crypto. +* [Sec 2781] Authentication doesn't protect symmetric associations against + DoS attacks. +* [Bug 2783] Quiet autoconf warnings about missing AC_LANG_SOURCE. +* [Bug 2789] Quiet compiler warnings from libevent. +* [Bug 2790] If ntpd sets the Windows MM timer highest resolution + pause briefly before measuring system clock precision to yield + correct results. +* Comment from Juergen Perlinger in ntp_calendar.c to make the code clearer. +* Use predefined function types for parse driver functions + used to set up function pointers. + Account for changed prototype of parse_inp_fnc_t functions. + Cast parse conversion results to appropriate types to avoid + compiler warnings. + Let ioctl() for Windows accept a (void *) to avoid compiler warnings + when called with pointers to different types. + +--- NTP 4.2.8p1 (Harlan Stenn <stenn@ntp.org>, 2015/02/04) Focus: Security and Bug fixes, enhancements. |
