AT-S63 Management Software Features Guide
Section II: Advanced Operations
185
Ping of Death Attack
The attacker sends an oversized, fragmented ICMP Echo (Ping) request
(greater than 65,535 bits) to the victim, which, if lacking a policy for
handling oversized packets, may freeze.
To defend against this form of attack, a switch port searches for the last
fragment of a fragmented ICMP Echo (Ping) request and examines its
offset to determine if the packet size is greater than 63,488 bits. If it is, the
fragment is forwarded to the switch’s CPU for final packet size
determination. If the switch determines that the packet is oversized, the
following occurs:
The switch sends an SNMP trap to the management stations.
The switch port is blocked for one minute.
Note
This defense mechanism requires some involvement by the switch’s
CPU, though not as much as the Teardrop defense. This does not
impact the forwarding of traffic between the switch ports, but it can
affect the handling of CPU events, such as the processing of IGMP
packets and spanning tree BPDUs. For this reason, Allied Telesis
recommends limiting the use of this defense, activating it only on
those ports where an attack is most likely to originate.
Also note that an attacker can circumvent the defense by sending a
stream of ICMP Echo (Ping) requests with a size of 63,488 to 65,534 bits.
A large number of requests could overwhelm the switch’s CPU.
Содержание AT-S63
Страница 14: ...Figures 14 ...
Страница 18: ...Tables 18 ...
Страница 28: ...28 Section I Basic Operations ...
Страница 58: ...Chapter 1 Overview 58 ...
Страница 76: ...Chapter 2 AT 9400Ts Stacks 76 Section I Basic Operations ...
Страница 96: ...Chapter 5 MAC Address Table 96 Section I Basic Operations ...
Страница 114: ...Chapter 8 Port Mirror 114 Section I Basic Operations ...
Страница 116: ...116 Section II Advanced Operations ...
Страница 146: ...Chapter 12 Access Control Lists 146 Section II Advanced Operations ...
Страница 176: ...Chapter 14 Quality of Service 176 Section II Advanced Operations ...
Страница 196: ...196 Section III Snooping Protocols ...
Страница 204: ...Chapter 18 Multicast Listener Discovery Snooping 204 Section III Snooping Protocols ...
Страница 216: ...Chapter 20 Ethernet Protection Switching Ring Snooping 216 Section III Snooping Protocols ...
Страница 218: ...218 Section IV SNMPv3 ...
Страница 234: ...234 Section V Spanning Tree Protocols ...
Страница 268: ...268 Section VI Virtual LANs ...
Страница 306: ...Chapter 27 Protected Ports VLANs 306 Section VI Virtual LANs ...
Страница 320: ...320 Section VII Internet Protocol Routing ...
Страница 360: ...Chapter 30 BOOTP Relay Agent 360 Section VII Routing ...
Страница 370: ...Chapter 31 Virtual Router Redundancy Protocol 370 Section VII Routing ...
Страница 372: ...372 Section VIII Port Security ...
Страница 402: ...Chapter 33 802 1x Port based Network Access Control 402 Section VIII Port Security ...
Страница 404: ...404 Section IX Management Security ...
Страница 436: ...Chapter 36 PKI Certificates and SSL 436 Section IX Management Security ...
Страница 454: ...Chapter 38 TACACS and RADIUS Protocols 454 Section IX Management Security ...
Страница 462: ...Chapter 39 Management Access Control List 462 Section IX Management Security ...
Страница 504: ...Appendix B SNMPv3 Configuration Examples 504 Security Model Security Level Storage Type SNMPv3 Parameters Continued ...
Страница 532: ...Appendix D MIB Objects 532 ...