Which one of the following attacks will pass through a network layer intrusion detection system undetected?

Once an intruder has gained access to a remote system with a valid username and password, the attacker will attempt to increase his privileges by escalating the used account to one that has increased privileges. such as that of an administrator. What would be the best countermeasure to protect against escalation of priveges?

You are attempting to map out the firewall policy for an organization. You discover your target system is one hop beyond the firewall. Using hping2, you send SYN packets with the exact TTL of the target system starting at port 1 and going up to port 1024. What is this process known as?

You are trying to compromise a Linux Machine and steal the password hashes for cracking with password brute forcing program. Where is the password file kept is Linux?

Bob is a Junior Administrator at ABC Company. On One of Linux machine he entered the following firewall rules:

iptables t filter A INPUT -p tcp –dport 23 j DROP

Why he entered the above line?

Jim’s Organization just completed a major Linux roll out and now all of the organization’s systems are running Linux 2.5 Kernel. The roll out expenses has posed constraints on purchasing other essential security equipment and software. The organization requires an option to control network traffic and also perform stateful inspection of traffic going into and out of the DMZ, which built-in functionality of Linux can achieve this?

Peter is a Linux network admin. As a knowledgeable security consultant, he turns to you to look for help on a firewall. He wants to use Linux as his firewall and use the latest freely available version that is offered. What do you recommend?

Select the best answer.

On a backdoored Linux box there is a possibility that legitimate programs are modified or trojaned. How is it possible to list processes and uids associated with them in a more reliable manner?

Clive is conducting a pen-test and has just port scanned a system on the network. He has identified the operating system as Linux and been able to elicit responses from ports 23, 25 and 53. He infers port 23 as running Telnet service, port 25 as running SMTP service and port 53 as running DNS service. The client confirms these findings and attests to the current availability of the services. When he tries to telnet to port 23 or 25, he gets a blank screen in response. On typing other commands, he sees only blank spaces or underscores symbols on the screen. What are you most likely to infer from this?

After studying the following log entries, what is the attacker ultimately trying to achieve as

inferred from the log sequence?

1. mkdir -p /etc/X11/applnk/Internet/.etc

2. mkdir -p /etc/X11/applnk/Internet/.etcpasswd

3. touch -acmr /etc/passwd /etc/X11/applnk/Internet/.etcpasswd

4. touch -acmr /etc /etc/X11/applnk/Internet/.etc

5. passwd nobody -d

6. /usr/sbin/adduser dns -d/bin -u 0 -g 0 -s/bin/bash

7. passwd dns -d

8. touch -acmr /etc/X11/applnk/Internet/.etcpasswd /etc/passwd

9. touch -acmr /etc/X11/applnk/Internet/.etc /etc