- I found that the networking staff had infiltrated every user’s mailbox (including the director’s), the payroll database, and the contributors’ database. - computation errors in the math coprocessor portion of the chip. - Even Ehud Tenebaum, the Israeli hacker known as “The Analyzer,” who achieved fame in 1998 as the mastermind of the biggest Pentagon attacks in history, joined the fray.. - On November 7, 2000 (the day of the U.S. - The company had a corporate policy stating that “pornographic sites will be blocked, and they cannot be accessed from the corporate network.” The company was filtering out access to sites. - Be readily accessible to all members of the organization.. - The first is “that which is not expressly permitted is denied;” the second is “that which is not expressly denied is permitted.” The first takes a firm stance with regard to security, while the latter is a more liberal approach.. - Define Each Issue This policy specifically addresses “access to Internet-based Web server resources.” The statement clearly defines the issue to which it pertains.. - Your Organization’s Position The statement goes on to declare that Internet access “shall only be allowed for the express purpose of performing work-related duties.” The organization’s stance is clear. - Contact Information for Further Details Finally, the policy directs, “For more information regarding what is considered appropriate Web server access of Internet resources, please consult your direct supervisor.” The policy tells readers what information is available and where to get it.. - “bending” the communication rules, so comprehending how network information is exchanged is vital to securing against such attacks.. - Preamble A preamble is a defined series of communication pulses that tells all receiving stations, “Get ready—I’ve got something to say.” The standard preamble is eight bytes long.. - This sequence information is also stored in the data portion of the frame.. - The first half of the address is the manufacturer’s identifier. - The second half of the MAC address is the serial number the manufacturer has assigned to the device.. - Each portion of the. - Figure 3.4 is a representation of the OSI model in all its glory. - Figure 3.4: The OSI model. - Figure 3.6: The effects of adding a router to the network. - For example, consider the vast size of the Internet. - This helps to insure that table updates are only accepted from trusted hosts.The drawback to this authentication method is that the password is transmitted as clear text. - Packet 21 shows “This workstation” (or FTP client) requesting that PASV FTP be used. - Each system is responsible for only a portion of the framework.. - Figure 3.18: A visual representation of the hierarchical structure of DNS. - Let’s say you’re part of the foobar.com domain. - Flagging allows a message to be marked as “seen,” “deleted,” or “answered.” This means that an IMAP client can be configured to collect only messages that have not been seen, avoiding the transfer of the entire mailbox.. - The dynamic information is data that pertains to the current state of the device. - The voltage level of the circuit is constantly changing. - This effect is somewhat similar to what happens to a water skier—the faster the boat travels, the closer to the top of the water the skier rides.. - The downside to all of this is that the electromagnetic radiation can be measured in order to “sniff” the signal traveling down the wire. - Signals can be received from almost every corner of the world. - every corner of the world. - A new variation of the traditional hub is the wireless hub. - A protocol-aware device will add the network address of the destination device to the data field of a frame. - Table 4.1 represents a summary of the information discussed in the preceding sections. - To date, this is why switches have dominated this area of the network.. - This can create a difficult situation—the connection is required for business, but now someone has access to the internal network from an area where security is not controlled by the organization. - For example, in Figure 5.3 the code states Protocol Unreachable. - Figure 5.5: The differences between static and dynamic packet filtering. - Figure 5.9: The effects of performing a FIN scan. - Since proxies must “understand” the application protocol being utilized, they can also implement protocol-specific security. - Appliances also limit an organization to one vendor for their entire security system, as opposed to using a modular system that could encourage “best of breed” for all components—the best operating system tied to the best firewall which feeds into the best analysis system, with all three coming from different vendors.. - This can be the IP address of the firewall itself or some other legal number. - Unlike hiding NAT, the external address of the firewall must be used. - This has a direct benefit of reducing the administrative burden of creating and managing duplicate user and group/ role accounts, and it also reduces complexity—the greatest enemy to any security system. - Table 6.2 lists some of the more common prompts.. - let that router figure out how to deliver it.” The default route should be configured to use your ISP’s router at the other end of the WAN link.. - If you start at the very back of the network or you can see that the default route entries lead all the way out to the Internet. - it makes its filtering determination based solely on the source address of the transmitting system.. - This is because that segment is directly connected to the Ethernet port of the router. - through,” the router will approve the packet of data, pass the information along to the routing process, which would then pass the traffic along to the Ethernet segment.. - to the router. - The third access list is labeled “look for port scanning.” This is accomplished by logging a specific port so that any activity is displayed on the console terminal. - The external interface of a router receives a packet originating on the internal (secure) side of the network.. - Finally, the IP address of the network to be protected is configured (in global configuration mode):. - NAT repeats this process for the duration of the session.. - Authentication is the process that verifies the identity of the user. - Some of the authentication schemes (or vendor technologies) that can be used with FireWall-1 include:. - in the body of the message. - For these reasons, our discussion will be limited to the NT version of the product. - The certificate key number on the inside jacket of the CD case. - The external IP address of the firewall. - Figure 7.6: The FireWall-1 Policy Editor (with the Security Policy 1 tab selected). - Figure 7.7: The Network Objects management screen. - Figure 7.8: The Workstation Properties screen. - Figure 7.9: The Interface Properties screen. - Figure 7.10: The Address Translation tab of the Workstation Properties screen. - Through the magic of the Internet, this initial packet of data is routed to the destination host. - Let’s look briefly at each of the rules shown in Figure 7.13. - You also need to modify the properties of the firewall itself. - If the last rule is “Drop all traffic from any source to any destination,” this property is not evaluated.. - Figure 7.16: The Match tab of the SMTP Definition box. - Figure 7.17: The Action1 tab of the SMTP Definition box. - This is the portion of the address that you want to rewrite. - The IDS sensor would do this, pretending to be the system on the other end of the connection. - Since it runs on the system you wish to protect, it is unaffected by the traffic isolation properties of the switch. - Figure 8.5: The Select Install Options screen of the RealSecure installation. - Figure 8.6: The Cryptographic Setup screen. - On the bottom of the screen is the Sensor view. - Figure 8.8: The RealSecure Console screen. - Figure 8.9: The Policies tab of the Network Sensor screen. - Note Remember—the more verification the IDS sensor must perform, the more horsepower it is going to require. - Figure 8.12: The Connection Events tab of the Policy Editor menu. - For the source address, use the IP address of the Web server. - Figure 8.13: The Responses tab of the Sensor Properties screen. - Figure 8.15: The Events tab of the Activity Tree window. - This creates the Event Inspector window, which provides a high level of detail—the source and destination IP addresses, the protocols, the source and destination ports, (including the information type and value), along with the actions taken. - The Destination tab yields much of the same detail. - You have seen some of the strengths and. - Figure 9.2: The POP3 server accepting the logon name. - Figure 9.3: The POP3 client sending the user’s password. - Figure 9.4: The POP3 server accepting the authentication attempt. - An initialization vector (IV) is added to the beginning of the data to insure that all blocks can be properly ciphered.. - This means that the crypto key must remain secret in order to insure the confidentiality of the ciphertext. - This creates a unique digital signature, which is appended to the end of the message. - As for the number of possible key combinations, this is directly proportional to the size of the cipher key. - One of the benefits of IPSec is that it is very convenient to use. - One of the biggest benefits of Kerberos is that it is freely available. - Created by NIST (National Institute for Standards and Technology), SHA-1 (Secure Hash Algorithm) is part of the U.S. - The two hosts will authenticate each other in the course of the
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