net security update

CentOS Errata and Security Advisory CESA-2015:1385

The net-snmp packages provide various libraries and tools for the Simple
Network Management Protocol (SNMP), including an SNMP library, an
extensible agent, tools for requesting or setting information from SNMP
agents, tools for generating and handling SNMP traps, a version of the
netstat command which uses SNMP, and a Tk/Perl Management Information Base
(MIB) browser.

A denial of service flaw was found in the way snmptrapd handled certain
SNMP traps when started with the “-OQ” option. If an attacker sent an SNMP
trap containing a variable with a NULL type where an integer variable type
was expected, it would cause snmptrapd to crash. (CVE-2014-3565)

This update also fixes the following bugs:

• The HOST-RESOURCES-MIB::hrSystemProcesses object was not implemented
  because parts of the HOST-RESOURCES-MIB module were rewritten in an earlier
  version of net-snmp. Consequently, HOST-RESOURCES-MIB::hrSystemProcesses
  did not provide information on the number of currently loaded or running
  processes. With this update, HOST-RESOURCES-MIB::hrSystemProcesses has been
  implemented, and the net-snmp daemon reports as expected. (BZ#1134335)

• The Net-SNMP agent daemon, snmpd, reloaded the system ARP table every 60
  seconds. As a consequence, snmpd could cause a short CPU usage spike on
  busy systems with a large APR table. With this update, snmpd does not
  reload the full ARP table periodically, but monitors the table changes
  using a netlink socket. (BZ#789500)

• Previously, snmpd used an invalid pointer to the current time when
  periodically checking certain conditions specified by the “monitor” option
  in the /etc/snmpd/snmpd.conf file. Consequently, snmpd terminated
  unexpectedly on start with a segmentation fault if a certain entry with the
  “monitor” option was used. Now, snmpd initializes the correct pointer
  to the current time, and snmpd no longer crashes on start. (BZ#1050970)

• Previously, snmpd expected 8-bit network interface indices when
  processing HOST-RESOURCES-MIB::hrDeviceTable. If an interface index of a
  local network interface was larger than 30,000 items, snmpd could terminate
  unexpectedly due to accessing invalid memory. Now, processing of all
  network sizes is enabled, and snmpd no longer crashes in the described
  situation. (BZ#1195547)

• The snmpdtrapd service incorrectly checked for errors when forwarding a
  trap with a RequestID value of 0, and logged “Forward failed” even though
  the trap was successfully forwarded. This update fixes snmptrapd checks and
  the aforementioned message is now logged only when appropriate.
  (BZ#1146948)

• Previously, snmpd ignored the value of the “storageUseNFS” option in the
  /etc/snmpd/snmpd.conf file. As a consequence, NFS drivers were shown as
  “Network Disks”, even though “storageUseNFS” was set to “2” to report them
  as “Fixed Disks” in HOST-RESOURCES-MIB::hrStorageTable. With this update,
  snmpd takes the “storageUseNFS” option value into account, and “Fixed Disks”
  NFS drives are reported correctly. (BZ#1125793)

• Previously, the Net-SNMP python binding used an incorrect size (8 bytes
  instead of 4) for variables of IPADDRESS type. Consequently, applications
  that were using Net-SNMP Python bindings could send malformed SNMP
  messages. With this update, the bindings now use 4 bytes for variables with
  IPADRESS type, and only valid SNMP messages are sent. (BZ#1100099)

• Previously, the snmpd service did not cut values in
  HOST-RESOURCES-MIB::hrStorageTable to signed 32-bit integers, as required
  by SNMP standards, and provided the values as unsigned integers. As a
  consequence, the HOST-RESOURCES-MIB::hrStorageTable implementation did not
  conform to RFC 2790. The values are now cut to 32-bit signed integers, and
  snmpd is therefore standard compliant. (BZ#1104293)

Users of net-snmp are advised to upgrade to these updated packages, which
contain backported patches to correct these issues.

Merged security bulletin from advisories:
https://lists.centos.org/pipermail/centos-cr-announce/2015-July/028295.html

Affected packages:
net-snmp
net-snmp-devel
net-snmp-libs
net-snmp-perl
net-snmp-python
net-snmp-utils

Upstream details at:
https://access.redhat.com/errata/RHSA-2015:1385