An attacker decided to crack the passwords used by industrial control systems. In this process, he employed a loop strategy to recover these passwords. He used one character at a time to check whether the first character entered is correct; if so, he continued the loop for consecutive characters. If not, he terminated the loop. Furthermore, the attacker checked how much time the device took to finish one complete password authentication process, through which he deduced how many characters entered are correct. What is the attack technique employed by the attacker to crack the passwords of the industrial control systems?
Correct Answer: C
Question 167
When analyzing the IDS logs, the system administrator noticed an alert was logged when the external router was accessed from the administrator's Computer to update the router configuration. What type of an alert is this?
Correct Answer: D
True Positive - IDS referring a behavior as an attack, in real life it is True Negative - IDS referring a behavior not an attack and in real life it is not False Positive - IDS referring a behavior as an attack, in real life it is not False Negative - IDS referring a behavior not an attack, but in real life is an attack. False Negative - is the most serious and dangerous state of all !!!!
Question 168
John, a professional hacker, decided to use DNS to perform data exfiltration on a target network, in this process, he embedded malicious data into the DNS protocol packets that even DNSSEC cannot detect. Using this technique. John successfully injected malware to bypass a firewall and maintained communication with the victim machine and C&C server. What is the technique employed by John to bypass the firewall?
Correct Answer: C
DNS tunneling may be a method wont to send data over the DNS protocol, a protocol which has never been intended for data transfer. due to that, people tend to overlook it and it's become a well-liked but effective tool in many attacks.Most popular use case for DNS tunneling is obtaining free internet through bypassing captive portals at airports, hotels, or if you are feeling patient the not-so-cheap on the wing Wi-Fi.On those shared internet hotspots HTTP traffic is blocked until a username/password is provided, however DNS traffic is usually still allowed within the background: we will encode our HTTP traffic over DNS and voila, we've internet access.This sounds fun but reality is, browsing anything on DNS tunneling is slow. Like, back to 1998 slow.Another more dangerous use of DNS tunneling would be bypassing network security devices (Firewalls, DLP appliances...) to line up an immediate and unmonitored communications channel on an organisation's network. Possibilities here are endless: Data exfiltration, fixing another penetration testing tool... you name it.To make it even more worrying, there's an outsized amount of easy to use DNS tunneling tools out there.There's even a minimum of one VPN over DNS protocol provider (warning: the planning of the web site is hideous, making me doubt on the legitimacy of it).As a pentester all this is often great, as a network admin not such a lot . How does it work:For those that ignoramus about DNS protocol but still made it here, i feel you deserve a really brief explanation on what DNS does: DNS is sort of a phonebook for the web , it translates URLs (human-friendly language, the person's name), into an IP address (machine-friendly language, the phone number). That helps us remember many websites, same as we will remember many people's names.For those that know what DNS is i might suggest looking here for a fast refresh on DNS protocol, but briefly what you would like to understand is:* A Record: Maps a website name to an IP address.example.com ? 12.34.52.67* NS Record (a.k.a. Nameserver record): Maps a website name to an inventory of DNS servers, just in case our website is hosted in multiple servers.example.com ? server1.example.com, server2.example.comWho is involved in DNS tunneling?* Client. Will launch DNS requests with data in them to a website .* One Domain that we will configure. So DNS servers will redirect its requests to an outlined server of our own.* Server. this is often the defined nameserver which can ultimately receive the DNS requests.The 6 Steps in DNS tunneling (simplified):1. The client encodes data during a DNS request. The way it does this is often by prepending a bit of knowledge within the domain of the request. for instance : mypieceofdata.server1.example.com2. The DNS request goes bent a DNS server.3. The DNS server finds out the A register of your domain with the IP address of your server.4. The request for mypieceofdata.server1.example.com is forwarded to the server.5. The server processes regardless of the mypieceofdata was alleged to do. Let's assume it had been an HTTP request.6. The server replies back over DNS and woop woop, we've got signal. Bypassing Firewalls through the DNS Tunneling Method DNS operates using UDP, and it has a 255-byte limit on outbound queries. Moreover, it allows only alphanumeric characters and hyphens. Such small size constraints on external queries allow DNS to be used as an ideal choice to perform data exfiltration by various malicious entities. Since corrupt or malicious data can be secretly embedded into the DNS protocol packets, even DNSSEC cannot detect the abnormality in DNS tunneling. It is effectively used by malware to bypass the firewall to maintain communication between the victim machine and the C&C server. Tools such as NSTX (https://sourceforge.net), Heyoka (http://heyoka.sourceforge.netuse), and Iodine (https://code.kryo.se) use this technique of tunneling traffic across DNS port 53. CEH v11 Module 12 Page 994
Question 169
Bill is a network administrator. He wants to eliminate unencrypted traffic inside his company's network. He decides to setup a SPAN port and capture all traffic to the datacenter. He immediately discovers unencrypted traffic in port UDP 161. what protocol is this port using and how can he secure that traffic?
Correct Answer: B
We have various articles already in our documentation for setting up SNMPv2 trap handling in Opsview, but SNMPv3 traps are a whole new ballgame. They can be quite confusing and complicated to set up the first time you go through the process, but when you understand what is going on, everything should make more sense. SNMP has gone through several revisions to improve performance and security (version 1, 2c and 3). By default, it is a UDP port based protocol where communication is based on a 'fire and forget' methodology in which network packets are sent to another device, but there is no check for receipt of that packet (versus TCP port when a network packet must be acknowledged by the other end of the communication link). There are two modes of operation with SNMP - get requests (or polling) where one device requests information from an SNMP enabled device on a regular basis (normally using UDP port 161), and traps where the SNMP enabled device sends a message to another device when an event occurs (normally using UDP port 162). The latter includes instances such as someone logging on, the device powering up or down, or a wide variety of other problems that would need this type of investigation. This blog covers SNMPv3 traps, as polling and version 2c traps are covered elsewhere in our documentation. SNMP trapsSince SNMP is primarily a UDP port based system, traps may be 'lost' when sending between devices; the sending device does not wait to see if the receiver got the trap. This means if the configuration on the sending device is wrong (using the wrong receiver IP address or port) or the receiver isn't listening for traps or rejecting them out of hand due to misconfiguration, the sender will never know. The SNMP v2c specification introduced the idea of splitting traps into two types; the original 'hope it gets there' trap and the newer 'INFORM' traps. Upon receipt of an INFORM, the receiver must send an acknowledgement back. If the sender doesn't get the acknowledgement back, then it knows there is an existing problem and can log it for sysadmins to find when they interrogate the device.
Question 170
Peter extracts the SIDs list from Windows 2000 Server machine using the hacking tool "SIDExtractor". Here is the output of the SIDs: From the above list identify the user account with System Administrator privileges.
