old notes

nslookup

#networking #dns #nslookup #dig #cname #aircrackng #UofTBootcamp

Follow-Up Questions from Homework9

Q2 – does it matter that we are getting non-authoritative answers from a recursive resolver (8.8.8.8) vs getting an authoritative one? – what is the difference between using this: nslookup -type=cname www.theforce.net And getting: Non-authoritative answer: www.theforce.net canonical name = theforce.net.

VS.

nslookup -type=cname theforce.net and getting: Non-authoritative answer: *** Can't find theforce.net: No answer

Authoritative answers can be found from: theforce.net origin = WebPublish_Othe mail addr = hostmaster serial = 2017110901 refresh = 900 retry = 600 expire = 86400 minimum = 3600

https://stackoverflow.com/questions/66014432/how-to-find-the-canonical-name-with-nslookup

Q3: – what does NX DOMAIN tell us for sure? https://bluecatnetworks.com/blog/what-you-can-learn-from-an-nxdomain-response/ – follow-up on conclusion

Networking Fundamentals: Homework 9

Your task is a crucial one: Restore the Resistance's core DNS infrastructure and verify that traffic is routing as expected.

Mission 1:

Network Issue:

The Resistence has taken down their primary DNS and email servers in order to a build and deply a new DNS and mail server but they are not currently receiving emails because they have no configured MX Records for the new email servers.

DNS record type found:

We want to check the MX records (mail exchanger records) which specify which mail servers can accept email that's sent to our domain with: starwars.com: nslookup -type=mx starwars.com

DNS records that can explain the reasons for existing network issue:

According to our nslookup results, the new mail servers are not listed. The primary mail server for starwars.com should be asltx.l.google.com and the secondary email should be asltx.2.google.com.

`Server: 192.168.2.1 Address: 192.168.2.1#53

Non-authoritative answer: starwars.com mail exchanger = 5 alt2.aspmx.l.google.com. starwars.com mail exchanger = 1 aspmx.l.google.com. starwars.com mail exchanger = 10 aspmx2.googlemail.com. starwars.com mail exchanger = 10 aspmx3.googlemail.com. starwars.com mail exchanger = 5 alt1.aspx.l.google.com.`

Instead, the primary server (indicated by the numeric value of 1 before the server address) is: aspmx.l.google.com. The secondary server is either: aspmx.l.google.com. or alt1.aspx.l.google.com. as both addresses have the next priority value of 5.

It's likely that these are the old servers and someone has forgotten to change the MX record configuration to the new servers at: asltx.l.google.com and asltx.2.google.com.

Recommended fixes to save the Galaxy!

The corrected MX record should be:

starwars.com mail exchanger = 1 asltx.l.google.com starwars.com mail exhanger = 2 asltx.2.google.com

Mission 2:

Network Issue:

Official emails are going into spam or being blocked because the SPF record has not been updated to reflect the new IP address of their mail server. Since the SPF record is used to indicate which mail servers are allowed to send emails on behalf of a domain, emails from the IP address of the new mail server (missing from the current SPF record) is likely to be filtered out as spam.

DNS record type found:

Looking up the SPF (Sender Policy Framework) record using nslookup -type=txt theforce.net | grep spf to find the following SPF record::

theforce.net text = "v=spf1 a mx mx:smtp.secureserver.net include:aspmx.googlemail.com ip4:104.156.250.80 ip4:45.63.15.159 ip4:45.63.4.215"

Alternatively, we can also use the dig DNS lookup utility: dig theforce.net txt | grep spf which confirms the same SPF record:

theforce.net. 3498 IN TXT "v=spf1 a mx mx:smtp.secureserver.net include:aspmx.googlemail.com ip4:104.156.250.80 ip4:45.63.15.159 ip4:45.63.4.215"

DNS records that can explain the reasons for existing network issues:

The servers currently configured to be allowed to send emails for the domain are from the following IPv4 hosts: 104.156.250.80, 45.63.15.159, and 45.63.4.215. The new one (45.23.176.21) has not beed added. It is likely that similar to Mission 1, someone has forgotten to update changes made while the network was down.

Recommended fixes to save the Galaxy!

We have not been given data regarding the other mail server IP addresses — if we assume that those are still correct and do not need to removed, we only need to add the missing IP so that the corrected record should be:

theforce.net. 3498 IN TXT "v=spf1 a mx mx:smtp.secureserver.net include:aspmx.googlemail.com ip4:104.156.250.80 ip4:45.63.15.159 ip4:45.63.4.215 ip4:45.23.176.21

Mission 3:

Network Issue:

DNS record type found:

We need to check the CNAME record of the resistance.theforce.net domain in order to see why it is not redirecting to theforce.net. A CNAME record is used to point one domain to another so if we want the resistance.theforce.net subdomain to point to theforce.net, we need to have the CNAME configured to do so.

DNS records that can explain the reasons for existing network issues:

Looking up the CNAME (Canonical Name) of www.theforce.net with nslookup in interactive mode in order to examine a correct CNAME configuration where www.theforce.net will be redirected to theforce.net:

nslookup to enter into interactive mode

> set query=CNAME to set the query type to CNAME > www.theforce.net to set the domain to query

This gives the following (relevant) output:

www.theforce.net canonical name = theforce.net.

Alternatively, we can also use single line command nslookup -type=CNAME www.theforce.net or dig www.theforce.net | grep CNAME if we like to confirm things in multiple ways before moving forward:

www.theforce.net. 2321 IN CNAME theforce.net. is the output from dig indicating the correct configuration.

Looking up why our resistance.theforce.net is not redirecting to theforce.net:

Using nslookup -type=CNAME resistance.theforce.net we get:** server can't find resistance.theforce.net: NXDOMAIN which is an error message indicating the DNS query failed because the domain name queried (resistance.theforce.net does not exist or that the query could not “know” that it exists.

This could mean (if we assume we have not made a user error in our query, i.e. mistyping the address): – the domain is currently offline or is having server issues – a security control blocking the domain – domain could be compromised or that malware exists

To follow-up, we can first check if the domain is offline using https://isitup.org/resistance.theforce.net which indicates that the domain is down. This makes sense because we are supposed to be redirecting resistance.theforce.net to the CNAME domain theforce.net so the subdomain should not exist on its own.

Recommended fixes to save the Galaxy!

To fix this, we need to correct the CNAME record configuration to have this line:

resistance.theforce.net canonical name = theforce.net.

Mission 4

Network Issue: DNS record type found: DNS records that can explain the reasons for existing network issues: Recommended fixes to save the Galaxy!

Mission 5:

Network Issue:

Slow network traffic from the planet of Batuu to Jedha due to an attack on Planet N.

The routing protocol in use is OSPF Open Shortest Path First.

Recommended fixes to save the Galaxy!

The new path to use is:

Mission 6:

Your Mission:

  • Figure out the Dark Side's secret wireless key by using Aircrack-ng.

Results from running Aircrack-ng with the password list downloaded from: https://github.com/danielmiessler/SecLists/blob/master/Passwords/WiFi-WPA/probable-v2-wpa-top4800.txt

`[00:00:00] 3432/4800 keys tested (10349.88 k/s)

Time left: 0 seconds 71.67%

KEY FOUND! [ dictionary ]

Master Key : B3 52 50 D0 9F 8E AB BD 0D 9E 3D D3 A3 62 12 82 9E FA 89 FC 19 1D A4 4A 3E 7A 40 9C D4 DF 68 DC

Transient Key : DF 26 D4 B0 47 58 E5 AB 33 66 35 14 87 70 7E 46 9E 93 3F 48 3A AE BE F5 0A 58 81 82 B1 59 56 A4 05 C4 04 F4 F0 E2 27 45 49 3D 51 9C A0 E0 AA 83 5F 63 D5 35 A5 56 52 24 35 70 31 08 BE 99 F6 15

EAPOL HMAC : 3E B9 D6 B8 63 69 A7 8B 83 EA 2A 3A 71 ED CF 59`

The password is: dictionary. We use this password to decrypt the WPA traffic via Wireshark.

  • Once you have decrypted the traffic, figure out the following Dark Side information:

    • Host IP Addresses and MAC Addresses by looking at the decrypted ARP traffic.

Host: Sender MAC address: IntelCor_55:98:ef (00:13:ce:55:98:ef) Sender IP address: 172.16.0.101 (172.16.0.101)

Looking for: Sender MAC address: Cisco-Li_e3:e4:01 (00:0f:66:e3:e4:01) Sender IP address: 172.16.0.1 (172.16.0.1)

Mission 7:

Viewing the DNS record from Mission #4, specifically looking for a hidden message in the TXT record:

nslookup -type=txt princessleia.site to find this message:

princessleia.site text = "Run the following in a command line: telnet towel.blinkenlights.nl or as a backup access in a browser: www.asciimation.co.nz"

Take a screen shot of the results:

Note: This was the coolest last homework question ever! And thank you for reading.

#wireshark #networking #ip #tcp #udp #arp #http #dns #aircrack #nslookup #cheatsheet #UofTBootCamp

General

!(arp or icmp or dns) filter out whatever udp contains xx:xx:xx filter for certain HEX values at any offset

Search by string/regex/hex value: Edit > Find Next > Select your Filter/Search Input

802.11

Wireshark Beacon Filter: wlan.fc.type_subtype = 0x08 Wireshark broadcast filter: eth.dst == ff:ff:ff:ff:ff:ff Wireshark multicast filter: (eth.dst[0] & 1)

ARP

arp.opcode == 1 for requests arp.opcode == 2 for responses

Operation code params: https://www.iana.org/assignments/arp-parameters/arp-parameters.xhtml#arp-parameters-1

DNS

queries: dns.flags.response == 0 responses: dns.flags.response == 1

errors: dns.flags.rcode == 0 no error dns.flags.rcode != 0 dns requests couldn't be correctly resolved. dns.flags.rcode == 3 no such name

examples dns.a dns.cname dns.qry.name == example.com dns.resp.name == example.com dns.resp.name == example.com and dns.time > 0.01

HTTP

http.request.method==GET http.request.method==POST. ip.addr==93.184.216.34 and http.request.method==GET

IP

ip.addr == < ip > ip.dest == < ip > ip.src == < ip > !(ip.addr == <ip>) range: ip.addr >= 10.10.50.1 and ip.addr <= 10.10.50.100 multiple: ip.addr == <ip> and ip.addr == <ip> subnet: ip.addr == 10.10.50.1/24 port: tcp.port == 25 or tcp.dstport == 23 ip and port: ip.addr == <ip> and Tcp.port == 25

TCP

handshake: SYN, SYN/ACK, ACK tcp.flags.syn ==1 && tcp.flags.ack == 0 to view only SYN tcp.flags.syn ==1 && tcp.flags.ack == 1 to view only SYN/ACK requests tcp.flags.syn == 0 && tcp.flags.ack == 1 to view only ACK

termination packets: tcp.flags.fin == 1

look for open port: (since it will respond with SYN/ACK) tcp.flags.syn == 1 && tcp.flags.ack == 1

display all TCP resets: (connection killed) tcp.flags.reset==1

packets that contain a certain term in packet: tcp contains xxx

Follow a tcp stream: tcp.stream eq X

Filter by seq num: tcp.seq == x

Detects push events for troubleshooting: tcp.flags.push == 1

nslookup

Syntax: nslookup -type=[NS record type] [domain] look up name server records

nslookup Option Description -domain=[domain-name] Change the default DNS name. -debug Show debugging information. -port=[port-number] Specify the port for queries. The default port number is 53. -timeout=[seconds] Specify the time allowed for the server to respond. -type=a View information about the DNS A address records. -type=any View all available records. -type=hinfo View hardware-related information about the host. -type=mx View Mail Exchange server information. -type=ns View Name Server records. -type=ptr View Pointer records. Used in reverse DNS lookups. -type=soa View Start of Authority records.

nslookup -type=txt <domain> for spf records

Aircrack-ng

  • syntax: Aircrack-ng [.pcap file name]
  • Note: the Wireless Toolbar no longer exists in view > it is now in: Wireshark > Preferences > Protocols > IEEE 802.11 for putting in relevant key

Word lists for WPA https://www.aircrack-ng.org/doku.php?id=faq#where_can_i_find_good_wordlists

#networking #OSI #wireshark #dns #nslookup #tcp #ip #80211 #email #UofTBootcamp #arp

Follow-Up Questions from Class Activities

  • Activity 9.2.09 on Email Security: missing emails? Why is SPF failing – can't see the email Networking Review Activity:
  • What networking devices use these values for mac addresses- don't they all?
  • What is the original source IP? 0.0.0.0??
  • CIDR & ip range review!! Network Attacks Review Activity:
  • if this is the only data, how can you know for sure which is good/which is mac address of hacker's device? [Duplicate IP address detected for 192.168.47.254 (00:0c:29:1d:b3:b1) - also in use by 00:50:56:f9:f5:54 (frame 2013)]

DNS

  • translates URI into IP address
  • DNS zone file: actual file containing all the DNS records for a particular domain
  • lives in DNS server
  • contains a TTL indicating how long a DNS cache will remember the information

DNS Record Types: CONTAINED IN DNS ZONE FILE

  • A Record: Translates domain to IP address
  • PTR Record: Translates IP into domain
  • CNAME Record: Alias record used to point one domain to another domain
  • SOA record: Contains administrative details about a domain, such as: email address of the administrator, TTL value, when the domain was last updated

MX Record: mail exchange: directs emails to specific mail server; if multiple, can be set with preferences

TXT Record: created to include human-readable notes

SPF record: Sender Policy Framework: determines if email is from a trusted server

  • type of TXT Record
  • indicates which mail servers are allowed to send emails on behalf of a domain by checking:
  • Check the sending mail server's IP address, 12.54.54.23.
  • Validate the DNS record of widget.com's SPF record to confirm the sending mail server's IP address is either 23.43.54.235 or 23.43.54.236 (the valid mail server IPs)
  • Since the sender's IP is 12.54.54.23 (not 23.43.54.235 or 23.43.54.236), gadgets.com's mail server can identify the email as spam and potentially reject it or send it to the recipient's spam folder.

nslookup

nslookup -type=[NS record type] [domain] look up name server records

To look up the MX record: nslookup -type=MX gadget.com

To look up the A record: nslookup -type=A gadget.com

To look up the SOA record: nslookup -type=SOA gadget.com

nslookup Option Description -domain=[domain-name] Change the default DNS name. -debug Show debugging information. -port=[port-number] Specify the port for queries. The default port number is 53. -timeout=[seconds] Specify the time allowed for the server to respond. -type=a View information about the DNS A address records. -type=any View all available records. -type=hinfo View hardware-related information about the host. -type=mx View Mail Exchange server information. -type=ns View Name Server records. -type=ptr View Pointer records. Used in reverse DNS lookups. -type=soa View Start of Authority records.

Email Headers

Some of the most important fields in this raw email are: – Return-Path: Specifies the sender's return email. – Delivered-To: Specifies the recipients email. – Received: Shows a list of mail servers, illustrating the path taken by the email from its source to destination. – Message-ID: A unique string created by the sending mail server as an identifier of the email. – Received SPF: The SPF verification field, which we will cover in more detail in the next activity.

Security Concerns for Emails

__ SPAM__: mitigate with using SPF records, matching list of known spam senders, and keyword identification Sending Confidential Emails across encrypted channels: – emails are typically routed across multiple mail servers – encryption tools: PGP: Pretty Good Privacy or S/MIME: Secure/Multipurpose Internet Mail Extensions – Email Spoofing

Detecting Email Spoofing:

(1) Check the From email header (2) Check the Received-SPF email header – Received-SPF uses the IP address from the Received field and determines if it's an IP of an authorized sender with pass/fail (3) Check the Received Email Header – look up the source IP of the mail server that sent the email – For example, the ARIN Whois/RDAP tool.

Class Activities

Analyzing DNS Records:

MX Record: splunk.com mail exchanger = 20 mx1.splunk.iphmx.com. splunk.com mail exchanger = 20 mx2.splunk.iphmx.com. Type A Record: Non-authoritative answer: Name: splunk.com Address: 52.5.196.118 Name Server Non-authoritative answer: splunk.com nameserver = ha2.markmonitor.zone. splunk.com nameserver = ha1.markmonitor.zone. splunk.com nameserver = ha4.markmonitor.zone. splunk.com nameserver = ha3.markmonitor.zone.

Bonus: dig nmap.org txt | grep "spf" gives us 3 servers authorized to send mail from:

nmap.org. 3600 IN TXT "v=spf1 a mx ptr ip4:45.33.49.119 ip6:2600:3c01::f03c:91ff:fe98:ff4e ip6:2600:3c01:e000:3e6::6d4e:7061 `include:_spf.google.com ~all"

Analyzing Email Headers Activity:

determine the following data points: Email 1: – Delivered-To: juliejones@acme.com – Return-Path: jonathanthomas@microsoft.com – IP address of source domain: 40.76.4.15 from: Received-SPF: pass (google.com: domain of jonathanthomas@microsoft.com designates 40.76.4.15 as permitted sender) client-ip=40.76.4.15; – Message-ID: 1689837351.2998569.1568044304435@mail.microsoft.com

Email 2: permitted by SPF but clearly spam – Delivered-To: juliejones@acme.com – Return-Path: xzvvvret34344@yahoo.com – IP address of source domain: 74.6.130.41 from: Received-SPF: pass (google.com: domain of xzvvvret34344@yahoo.com designates 74.6.130.41 as permitted sender) client-ip=74.6.130.41; – Message-ID: 1689837351.2998569.1568044304435@mail.yahoo.com

Email 3: – Delivered-To: juliejones@acme.com – Return-Path: timmytom@widgets.com – IP address of source domain: 34.86.130.4 from: Received-SPF: fail (google.com: domain of timmytom@widgets.com does not designate 34.86.130.49 as permitted sender) client-ip=34.86.130.49 ; – Message-ID: 1gytrdd9837351.987987abs9.1568044304435@mail.widgets.com

Networking Review Activity

A. Answer the following questions on HTTP: 7. What is the the port number range that this port is part of? 58424 or 62412 There are 49,152 – 65,535 dynamic and/or private ports.

  • Under Ethernet II is a value of Destination: Technico_65:1a:36 (88:f7:c7:65:1a:36)
    1. What does this value represent? MAC address of physical device where this is going
    2. Which OSI layer does this exist in? Datalink (2)
    3. What networking devices use these values? Don't all devices?

Part Two: ARP

  1. What type of networking request does ARP first make? Broadcast

B. Use a filter to find the count of ARP responses, and answer the following questions:

arp.opcode 0 Reserved [RFC5494] 1 REQUEST [RFC826][RFC5227] 2 REPLY [RFC826][RFC5227]

arp.opcode == 1 for requests arp.opcode == 2 for responses

  1. What is the IP of the device that is responding? Sender MAC address: IntelCor_10:ac:c0 (a0:a4:c5:10:ac:c0) Sender IP address: 10.0.0.32 (10.0.0.32)

  2. To what IP is the device responding to? Target IP address: c66251b0-093d Target MAC address: c66251b0-093d-7d9c-4f7c-c2fc9df7c3ca.local (e4:f0:42:3b:7a:de) -7d9c-4f7c-c2fc9df7c3ca.local (10.0.0.10)

  3. Write out in simple terms what has taken place, describing the request and response. Host makes a broadcast to find the MAC address of the IP = request. Response = information locating the MAC address.

DHCP B. Use a filter to view the DHCP Discover, and answer the following questions on that packet:

###1. What is the original source IP? 0.0.0.0????###

  1. Why does it have that value? Unknown IP – usually to indicate that the local IP address is not assigned.

  2. What is the original destination IP? Internet Protocol Version 4, Src: 0.0.0.0 (0.0.0.0), Dst: 255.255.255.255 (255.255.255.255)

  3. What does that value signify? broadcast

C. Use a filter to view the DHCP ACK, and answer the following questions on that packet. dhcp.option.dhcp == 5

### 1. Explain in simple terms what is happening in this packet.

  • DHCP Ack server which received the DHCP request message fro client checks if the IP address shown in the DHCP Server Identifier matches its own

  • broadcasts a DHCP Ack message ensuring client can receive the message -transfer net config data to client including:

    • IP address
    • Subnet mask
    • Default gateway IP address
    • DNS server IP address
    • Lease time (during which a client can use the IP address allocated/leased by a DHCP server)

    1. Define the term “DHCP lease.” Amount of time in minutes or seconds a network device can use an IP address in a network. IP is reserved for that device until expiration.

    2. What is the DHCP lease time provided in this packet? IP Address Lease Time: (604800s) 7 days

    3. What are the steps in a TCP connection? SYN, SYN-ACK, ACK

    4. What are the steps in a TCP termination? FIN. ACK, FIN, ACK

    5. What steps appear in the packets displayed? the handshake steps

    6. What type of activity/protocol is TCP establishing a connection for? in this case http – TCP is generally used to provide reliable stream delivery service, i.e. delivering data as a stream of bytes and deceiving data as a stream of bytes.

    7. What is the website name being accessed after the TCP connection? Host: sportingnews.com\r\n

Topologies

  1. What are the Topologies for A, B, C? Tree, Hybrid of Bus and Tree, Disconnected ring?

  2. What are the advantages and disadvantages for each?

    • Network Devices

  3. In the network devices illustration, what are numbers one through four? Internet, Firewall, router, Switch

  4. What does the dashed line represent in number five? firewall security?

  5. What is a load balancer? distributes traffic across multiple servers to improve application availability and responsiveness and prevent server overload

4. Where would you place a load balancer? Between access and servers? Internet || servers or switch || servers?

  • Network Routing
  • Which routing protocols use distance as criteria? Distance Vector Routing Protocols:
  • RIP (Routing Information protocol)
  • EIGRP (Enhanced Interior Gateway Routing Protocol)
  1. Which routing protocols use speed as criteria? Link-State Routing Protocols
  2. OSPF: Open Shortest Path First

Part Six: Network Addressing:

  1. Define binary. base-2 number system (0 and 1s) used to write machine code

  2. What are IP addresses used for? network interface identification and location addressing

  3. What are the two primary versions of IP addresses? IPv4 and IPv6

  4. How many octets are in a IPV4 address? IPv4 – 32 bits – 4 octects IPv6 – 128 bits – 16 octets

  5. What is the difference between primary and public IP addresses? private is within a network or subnet, public is on the internet and unique.

8. What is CIDR? “Classless Inter-Domain routing”

  • allocating IP addesses and IP routing

9. What is the range of IP addresses in: 192.18.65.0/24?

Network Attacks Review Activity

  • ARP spoof attack – redirects traffic
  • DHCP starvation attack – floods with DHCP requests so runs out of IP, type of denial of service
  • TCP packets show port scanning,
  • Wireless Attacks:
  • What are the different security types available for Wireless communications? List them in order from least to most secure. WEP – WPA – WPA2

  1. What is 802.11? Wifi Standard (protocol)

  2. What is an SSID? a more recognizable format of how a networking hardware device identifies itself as broadcasting a wireless signal beacon

  3. What is the name of the the signal a WAP sends out identifying its SSID? beacon

  4. If a user has WEP encrypted wireless, what is a potential negative outcome? it's old and hackable easily with aircrack-ng