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Friday, 18 December 2009 22:42 |
NTP (Network Time Protocol) contains a vulnerability in the handling of mode 7 requests, which can result in a denial-of-service condition. NTP mode 7 (MODE_PRIVATE) is used by the ntpdc query and control utility. In contrast, ntpq uses NTP mode 6 (MODE_CONTROL), while routine NTP time transfers use modes 1 through 5. Upon receipt of an incorrect mode 7 request or a mode 7 error response from an address that is not listed in a "restrict ... noquery" or "restrict ... ignore" segment, ntpd will reply with a mode 7 error response and log a message. If an attacker spoofs the source address of ntpd host A in a mode 7 response packet sent to ntpd host B, both A and B will continuously send each other error responses, for as long as those packets get through. If an attacker spoofs an address of ntpd host A in a mode 7 response packet sent to ntpd host A, then host A will respond to itself endlessly, consuming CPU and logging excessively. Before taking any action please ensure that you are viewing the latest official version of this security advisory by referencing http://www.nortel.com/securityadvisories For more information: Please contact your next level of support or visit http://www.nortel.com/contact for support numbers within your region. Nortel security advisories: http://nortel.com/securityadvisories Nortel Partner Information Center (PIC) website: http://www.nortelnetworks.com/pic
Source : http://support.nortel.com/go/main.jsp?cscat=BLTNDETAIL&DocumentOID=985679&poid=
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