The remote Redhat Enterprise Linux 7 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2015:2231 advisory.

    The Network Time Protocol (NTP) is used to synchronize a computer's time     with another referenced time source. These packages include the ntpd     service which continuously adjusts system time and utilities used to query     and configure the ntpd service.

    It was found that because NTP's access control was based on a source IP     address, an attacker could bypass source IP restrictions and send     malicious control and configuration packets by spoofing ::1 addresses.
    (CVE-2014-9298, CVE-2014-9751)

    A denial of service flaw was found in the way NTP hosts that were peering     with each other authenticated themselves before updating their internal     state variables. An attacker could send packets to one peer host, which     could cascade to other peers, and stop the synchronization process among     the reached peers. (CVE-2015-1799)

    A flaw was found in the way the ntp-keygen utility generated MD5 symmetric     keys on big-endian systems. An attacker could possibly use this flaw to     guess generated MD5 keys, which could then be used to spoof an NTP client     or server. (CVE-2015-3405)

    A stack-based buffer overflow was found in the way the NTP autokey protocol     was implemented. When an NTP client decrypted a secret received from an NTP     server, it could cause that client to crash. (CVE-2014-9297, CVE-2014-9750)

    It was found that ntpd did not check whether a Message Authentication Code     (MAC) was present in a received packet when ntpd was configured to use     symmetric cryptographic keys. A man-in-the-middle attacker could use this     flaw to send crafted packets that would be accepted by a client or a peer     without the attacker knowing the symmetric key. (CVE-2015-1798)

    The CVE-2015-1798 and CVE-2015-1799 issues were discovered by Miroslav     Lichvr of Red Hat.

    Bug fixes:

    * The ntpd service truncated symmetric keys specified in the key file to 20     bytes. As a consequence, it was impossible to configure NTP authentication     to work with peers that use longer keys. With this update, the maximum key     length has been changed to 32 bytes. (BZ#1191111)

    * The ntpd service could previously join multicast groups only when     starting, which caused problems if ntpd was started during system boot     before network was configured. With this update, ntpd attempts to join     multicast groups every time network configuration is changed. (BZ#1207014)

    * Previously, the ntp-keygen utility used the exponent of 3 when generating     RSA keys. Consequently, generating RSA keys failed when FIPS mode was     enabled. With this update, ntp-keygen has been modified to use the exponent     of 65537, and generating keys in FIPS mode now works as expected.
    (BZ#1191116)

    * The ntpd service dropped incoming NTP packets if their source port was     lower than 123 (the NTP port). With this update, ntpd no longer checks the     source port number, and clients behind NAT are now able to correctly     synchronize with the server. (BZ#1171640)

    Enhancements:

    * This update adds support for configurable Differentiated Services Code     Points (DSCP) in NTP packets, simplifying configuration in large networks     where different NTP implementations or versions are using different DSCP     values. (BZ#1202828)

    * This update adds the ability to configure separate clock stepping     thresholds for each direction (backward and forward). Use the stepback     and stepfwd options to configure each threshold. (BZ#1193154)

    * Support for nanosecond resolution has been added to the Structural     Health Monitoring (SHM) reference clock. Prior to this update, when a     Precision Time Protocol (PTP) hardware clock was used as a time source to     synchronize the system clock, the accuracy of the synchronization was     limited due to the microsecond resolution of the SHM protocol. The     nanosecond extension in the SHM protocol now allows sub-microsecond     synchronization of the system clock. (BZ#1117702)

    All ntp users are advised to upgrade to these updated packages, which     contain backported patches to correct these issues and add these     enhancements.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Detections

Analytics

RHEL 7 : ntp (RHSA-2015:2231)

high Nessus Plugin ID 86975

Version 2.14