Free GIAC GSNA Practice Exam with Questions & Answers | Set: 7

Secure Sockets Layer (SSL) is a protocol used to transmit private documents via the Internet. SSL uses a combination of public key and symmetric encryption to provide communication privacy, authentication, and message integrity. Using the SSL protocol, clients and servers can communicate in a way that prevents eavesdropping and tampering of data on the Internet. Many Web sites use the SSL protocol to obtain confidential user information, such as credit card numbers. By convention, URLs that require an SSL connection start with https: instead of http:. By default, SSL uses port 443 for secured communication. For a SSL connection between a Web browser and Web server, you must enter https, for example, "https://www.vzen.com ", instead of http as the protocol type in the URL. This will instruct the Web browser to use a different port for communication. SSL uses TCP port 443 for communication.

To ensure fault tolerance among the servers and to get the highest possible level of security and encryption for OWA clients, you must install two front-end Exchange 2000 servers. Place the new servers on the perimeter network and configure load balancing between them. To enhance security, you should also configure Certificate Services and create a rule on the firewall to redirect port 443 to the servers. The most secure firewall configuration is placing a firewall on either side of the front-end servers. This isolates the front-end servers in a perimeter network, commonly referred to as a demilitarized zone (DMZ). It is always better to configure more than one front-end server to get fault tolerance.

Packet filtering firewalls work on the first three layers of the OSI reference model, which means all the work is done between the network and physical layers. When a packet originates from the sender and filters through a firewall, the device checks for matches to any of the packet filtering rules that are configured in the firewall and drops or rejects the packet accordingly. In a software firewall, packet filtering is done by a program called a packet filter. The packet filter examines the header of each packet based on a specific set of rules, and on that basis, decides to prevent it from passing (called DROP) or allow it to pass (called ACCEPT). A packet filter passes or blocks packets at a network interface based on source and destination addresses, ports, or protocols. The process is used in conjunction with packet mangling and Network Address Translation (NAT). Packet filtering is often part of a firewall program for protecting a local network from unwanted intrusion. This type of firewall can be best used for network perimeter security. Answer: B is incorrect. An Intrusion detection system (IDS) is software and/or hardware designed to detect unwanted attempts at accessing, manipulating, and/or disabling of computer systems, mainly through a network, such as the Internet. These attempts may take the form of attacks, as examples, by crackers, malware and/or disgruntled employees. An IDS cannot directly detect attacks within properly encrypted traffic. An intrusion detection system is used to detect several types of malicious behaviors that can compromise the security and trust of a computer system. This includes network attacks against vulnerable services, data driven attacks on applications, host based attacks such as privilege escalation, unauthorized logins and access to sensitive files, and malware (viruses, trojan horses, and worms). Answer: A is incorrect. A proxy server exists between a client's Web-browsing program and a real Internet server. The purpose of the proxy server is to enhance the performance of user requests and filter requests. A proxy server has a database called cache where the most frequently accessed Web pages are stored. The next time such pages are requested, the proxy server is able to suffice the request locally, thereby greatly reducing the access time. Only when a proxy server is unable to fulfill a request locally does it forward the request to a real Internet server. The proxy server can also be used for filtering user requests. This may be done in order to prevent the users from visiting non-genuine sites. Answer: D is incorrect. A honeypot is a term in computer terminology used for a trap that is set to detect, deflect, or in some manner counteract attempts at unauthorized use of information systems. Generally it consists of a computer, data, or a network site that appears to be part of a network, but is actually isolated, and monitored, and which seems to contain information or a resource of value to attackers.

The cat data.txt.* command will display both the splitted files, and the > command will redirect the output into a new data.txt file.

In the pre-attack phase, there are seven steps, which have been defined by the EC-Council, as follows: 1.Information gathering 2.Determining network range 3.Identifying active machines 4.Finding open ports and applications 5.OS fingerprinting 6.Fingerprinting services 7.Mapping the network Answer: C is incorrect. In the enumeration phase, the attacker gathers information such as the network user and group names, routing tables, and Simple Network Management Protocol (SNMP) data. The techniques used in this phase are as follows: 1.Obtaining Active Directory information and identifying vulnerable user accounts 2.Discovering NetBIOS names 3.Employing Windows DNS queries 4.Establishing NULL sessions and queries

SQL buffer stores the most recently used SQL commands and PL/SQL blocks. It does not store the SQL* Plus commands. The SQL buffer can be edited or saved to a file. A SQL command or a PL/SQL block can be executed by entering a semicolon (;) or a slash (/), or by using the RUN command at the command prompt. When a semicolon (;) is entered at the end of a command, the command is completed and executed. When a slash (/) is entered on a new line, the command in the buffer is executed. It can also be used to execute a PL/SQL block. The RUN command is used to execute a command in the buffer. A SQL command can be saved in the buffer by entering a blank line. Reference: Oracle8i Online Documentation, Contents: "SQL*PLUS Users Guide and Reference", "Learning SQL*PLUS Basics, 3 of 4"

Contactless tokens are the third main type of physical tokens. Unlike connected tokens, they form a logical connection to the client computer but do not require a physical connection. The absence of the need for physical contact makes them more convenient than both connected and disconnected tokens. As a result, contactless tokens are a popular choice for keyless entry systems and electronic payment solutions such as Mobil Speedpass, which uses RFID to transmit authentication information from a keychain token. However, there have been various security concerns raised about RFID tokens after researchers at Johns Hopkins University and RSA Laboratories discovered that RFID tags could be easily cracked and cloned. Another downside is that contactless tokens have relatively short battery lives, usually only 3-5 years, which is low compared to USB tokens which may last up to 10 years. However, some tokens do allow the batteries to be changed, thus reducing costs. Answer: A is incorrect. Virtual tokens are a new concept in multi-factor authentication first introduced in 2005 by security company Sestus. Virtual tokens work by sharing the token generation process between the Internet website and the user's computer and have the advantage of not requiring the distribution of additional hardware or software. In addition, since the user's device is communicating directly with the authenticating website, the solution is resistant to man-in-the-middle attacks and similar forms of online fraud. Answer: B is incorrect. Connected tokens are tokens that must be physically connected to the client computer. Tokens in this category will automatically transmit the authentication information to the client computer once a physical connection is made, eliminating the need for the user to manually enter the authentication information. However, in order to use a connected token, the appropriate input device must be installed. The most common types of physical tokens are smart cards and USB tokens, which require a smart card reader and a USB port, respectively. Answer: C is incorrect. Disconnected tokens have neither a physical nor logical connection to the client computer. They typically do not require a special input device, and instead use a built-in screen to display the generated authentication data, which the user enters manually via a keyboard or keypad. Disconnected tokens are the most common type of security token used (usually in combination with a password) in two-factor authentication for online identification.

AS PATH Inference is one of the prominent techniques used for creating Internet maps. This technique relies on various BGP collectors that collect information such as routing updates and tables and provide this information publicly. Each BGP entry contains a Path Vector attribute called the AS Path. This path represents an autonomous system forwarding path from a given origin for a given set of prefixes. These paths can be used to infer AS-level connectivity and in turn be used to build AS topology graphs. However, these paths do not necessarily reflect how data is actually forwardeA, Ddjacencies between AS nodes only represent a policy relationship between them. A single AS link can in reality be several router links. It is also much harder to infer peering between two AS nodes, as these peering relationships are only propagated to an ISP's customer networks. Nevertheless, support for this type of mapping is increasing as more and more ISP's offer to peer with public route collectors such as Route-Views and RIPE. New toolsets are emerging such as Cyclops and NetViews that take advantage of a new experimental BGP collector BGPMon. NetViews can not only build topology maps in seconds but visualize topology changes moments after occurring at the actual router. Hence, routing dynamics can be visualized in real time. Answer: B is incorrect. There is no such Internet mapping technique.

Answer: D is incorrect. Firewalking is a technique for gathering information about a remote network protected by a firewall. This technique can be used effectively to perform information gathering attacks. In this technique, an attacker sends a crafted packet with a TTL value that is set to expire one hop past the firewall. If the firewall allows this crafted packet through, it forwards the packet to the next hop. On the next hop, the packet expires and elicits an ICMP "TTL expired in transit" message to the attacker. If the firewall does not allow the traffic, there should be no response, or an ICMP "administratively prohibited" message should be returned to the attacker. A malicious attacker can use firewalking to determine the types of ports/protocols that can bypass the firewall. To use firewalking, the attacker needs the IP address of the last known gateway before the firewall and the IP address of a host located behind the firewall. The main drawback of this technique is that if an administrator blocks ICMP packets from leaving the network, it is ineffective. Answer: A is incorrect. Path MTU discovery (PMTUD) is a technique in computer networking for determining the maximum transmission unit (MTU) size on the network path between two Internet Protocol (IP) hosts, usually with the goal of avoiding IP fragmentation. Path MTU discovery works by setting the DF (Don't Fragment) option bit in the IP headers of outgoing packets. Then, any device along the path whose MTU is smaller than the packet will drop it, and send back an ICMP "Fragmentation Needed" (Type 3, Code 4) message containing its MTU, allowing the source host to reduce its path MTU appropriately. The process repeats until the MTU is small enough to traverse the entire path without fragmentation. If the path MTU changes after the connection is set up and is lower than the previously determined path MTU, the first large packet will cause an ICMP error and the new, lower path MTU will be found. Conversely, if PMTUD finds that the path allows a larger MTU than what is possible on the lower link, the OS will periodically reprobe to see if the path has changed and now allows larger packets. On Linux this timer is set by default to ten minutes.

NetStumbler, a war driving tool, uses an organizationally unique identifier (OID) of 0x00601A, D protocol identifier (PID) of 0x0001. Each version has a typical payload string. For example, NetStumbler 3.2.3 has a payload string: 'All your 802.11b are belong to us'. Therefore, when you see the OID and PID values, you discover that the attacker is using NetStumbler, and when you see the payload string, you are able to ascertain that the attacker is using NetStumbler 3.2.3.

In DNS poisoning attack, an attacker distributes incorrect IP address. DNS cache poisoning is a maliciously created or unintended situation that provides data to a caching name server that did not originate from authoritative Domain Name System (DNS) sources. Once a DNS server has received such non-authentic datA, Caches it for future performance increase, it is considered poisoned, supplying the non-authentic data to the clients of the server. To perform a cache poisoning attack, the attacker exploits a flaw in the DNS software. If the server does not correctly validate DNS responses to ensure that they are from an authoritative source, the server will end up caching the incorrect entries locally and serve them to other users that make the same request. Answer: B is incorrect. IP (Internet Protocol) address spoofing is an attack in which an attacker creates the IP packets with a forged (spoofed) source IP address with the purpose of concealing the identity of the sender or impersonating another computing system. The basic protocol for sending data over the Internet and many other computer networks is the Internet Protocol ("IP"). The header of each IP packet contains, among other things, the numerical source and destination address of the packet. The source address is normally the address that the packet was sent from. By forging the header so it contains a different address, an attacker can make it appear that the packet was sent by a different machine. The machine that receives spoofed packets will send response back to the forged source address, which means that this technique is mainly used when the attacker does not care about the response or the attacker has some way of guessing the response. Answer: D is incorrect. Man-in-the-middle attacks occur when an attacker successfully inserts an intermediary software or program between two communicating hosts. The intermediary software or program allows attackers to listen to and modify the communication packets passing between the two hosts. The software intercepts the communication packets and then sends the information to the receiving host. The receiving host responds to the software, presuming it to be the legitimate client. Answer: C is incorrect. MAC flooding is a technique employed to compromise the security of network switches. In a typical MAC flooding attack, a switch is flooded with packets, each containing different source MAC addresses. The intention is to consume the limited memory set aside in the switch to store the MAC address-to-physical port translation table. The result of this attack causes the switch to enter a state called failopen mode, in which all incoming packets are broadcast out on all ports (as with a hub), instead of just down the correct port as per normal operation. A malicious user could then use a packet sniffer (such as Wireshark) running in promiscuous mode to capture sensitive data from other computers (such as unencrypted passwords, e-mail and instant messaging conversations), which would not be accessible were the switch operating normally.