What happens when one experiences a ping of death?
Answer(s): B
A hacker can send an IP packet to a vulnerable machine such that the last fragment contains an offest where (IP offset *8) + (IP data length)>65535. This means that when the packet is reassembled, its total length is larger than the legal limit, causing buffer overruns in the machine's OS (becouse the buffer sizes are defined only to accomodate the maximum allowed size of the packet based on RFC 791)...IDS can generally recongize such attacks by looking for packet fragments that have the IP header's protocol field set to 1 (ICMP), the last bit set, and (IP offset *8)+(IP data length)>65535" CCIE Professional Development Network Security Principles and Practices by Saadat Malik pg 414 "Ping of Death" attacks cause systems to react in an unpredictable fashion when receiving oversized IP packets. TCP/IP allows for a maximum packet size of up to 65536 octets (1 octet = 8 bits of data), containing a minimum of 20 octets of IP header information and zero or more octets of optional information, with the rest of the packet being datA. Ping of Death attacks can cause crashing, freezing, and rebooting.
Which one of the following network attacks takes advantages of weaknesses in the fragment reassembly functionality of the TCP/IP protocol stack?
Answer(s): A
The teardrop attack uses overlapping packet fragments to confuse a target system and cause the system to reboot or crash.
A denial of Service (DoS) attack works on the following principle:
Answer(s): D
Denial-of-service (often abbreviated as DoS) is a class of attacks in which an attacker attempts to prevent legitimate users from accessing an Internet service, such as a web site. This can be done by exercising a software bug that causes the software running the service to fail (such as the “Ping of Death” attack against Windows NT systems), sending enough data to consume all available network bandwidth (as in the May, 2001 attacks against Gibson Research), or sending data in such a way as to consume a particular resource needed by the service.
What happens during a SYN flood attack?
To a server that requires an exchange of a sequence of messages. The client system begins by sending a SYN message to the server. The server then acknowledges the SYN message by sending a SYN-ACK message to the client. The client then finishes establishing the connection by responding with an ACK message and then data can be exchanged. At the point where the server system has sent an acknowledgment (SYN-ACK) back to client but has not yet received the ACK message, there is a half-open connection. A data structure describing all pending connections is in memory of the server that can be made to overflow by intentionally creating too many partially open connections. Another common attack is the SYN flood, in which a target machine is flooded with TCP connection requests. The source addresses and source TCP ports of the connection request packets are randomized; the purpose is to force the target host to maintain state information for many connections that will never be completed. SYN flood attacks are usually noticed because the target host (frequently an HTTP or SMTP server) becomes extremely slow, crashes, or hangs. It's also possible for the traffic returned from the target host to cause trouble on routers; because this return traffic goes to the randomized source addresses of the original packets, it lacks the locality properties of "real" IP traffic, and may overflow route caches. On Cisco routers, this problem often manifests itself in the router running out of memory.
What is the term 8 to describe an attack that falsifies a broadcast ICMP echo request and includes a primary and secondary victim?
Trojan and Back orifice are Trojan horse attacks. Man in the middle spoofs the Ip and redirects the victems packets to the cracker The infamous Smurf attack. preys on ICMP's capability to send traffic to the broadcast address. Many hosts can listen and respond to a single ICMP echo request sent to a broadcast address.Network Intrusion Detection third Edition by Stephen Northcutt and Judy Novak pg 70 The "smurf" attack's cousin is called "fraggle", which uses UDP echo packets in the same fashion as the ICMP echo packets; it was a simple re-write of "smurf".
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