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Cross-Platform Release Notes for Cisco IOS Release 12.0S
OL-1617-14 Rev. Q0
Caveats
Resolved Caveats—Cisco IOS Release 12.0(32)S15
Further Problem Description: This vulnerability occurs on multiple events to be exploited. It is
medium complexity in order to exploit and has never been seen in a customer environment.
CSCsz72591
Symptoms: A router crashes with an Address Error (load or instruction fetch) exception.
Conditions: The router must be configured to act as a DHCP client.
Workaround: There is no workaround.
CSCtd75033
Symptoms: Cisco IOS Software is affected by NTP mode 7 denial-of-service vulnerability.
Conditions: Cisco IOS Software with support for Network Time Protocol (NTP) contains a
vulnerability processing specific NTP Control Mode 7 packets. This results in increased CPU on the
device and increased traffic on the network segments.
This is the same as the vulnerability which is described in http://www.kb.cert.org/vuls/id/568372.
Cisco has release a public facing vulnerability alert at the following link:
http://tools.cisco.com/security/center/viewAlert.x?alertId=19540
Cisco IOS Software that has support for NTPv4 is NOT affected. NTPv4 was introduced into
Cisco IOS Software: 12.4(15)XZ, 12.4(20)MR, 12.4(20)T, 12.4(20)YA, 12.4(22)GC1, 12.4(22)MD,
12.4(22)YB, 12.4(22)YD, 12.4(22)YE and 15.0(1)M.
All other versions of Cisco IOS and Cisco IOS XE Software are affected.
To see if a device is configured with NTP, log into the device and issue the CLI command show
running-config | include ntp. If the output returns either of the following commands listed then the
device is vulnerable:
ntp master <any following commands>
ntp peer <any following commands>
ntp server <any following commands>
ntp broadcast client
ntp multicast client
The following example identifies a Cisco device that is configured with NTP:
router#show running-config | include ntp
ntp peer 192.168.0.12
The following example identifies a Cisco device that is not configured with NTP:
router#show running-config | include ntp
router#
To determine the Cisco IOS Software release that is running on a Cisco product, administrators can
log in to the device and issue the show version command to display the system banner. The system
banner confirms that the device is running Cisco IOS Software by displaying text similar to
“Cisco Internetwork Operating System Software” or “Cisco IOS Software.” The image name
displays in parentheses, followed by “Version” and the Cisco IOS Software release name. Other
Cisco devices do not have the show version command or may provide different output.
The following example identifies a Cisco product that is running Cisco IOS Software
Release 12.3(26) with an installed image name of C2500-IS-L:
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