Developing hypotheses for Threat Hunting with ChatGPT

Saniye Nur
21 min readJan 2, 2023

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Can you create a hypothesis for threat hunting scenarios?

A hypothesis is a proposed explanation for a phenomenon that can be tested through further investigation. In the context of threat hunting, a hypothesis might be a proposed explanation for suspicious or anomalous activity that has been observed on a network or system.

Here are some examples of hypotheses that might be used in threat hunting scenarios:

  1. A network connection to a known malicious IP address could indicate that an endpoint on the network has been compromised.
  2. An unusual spike in network traffic could indicate a distributed denial of service (DDoS) attack.
  3. An unexpected process running on a server could indicate the presence of malware.
  4. Unauthorized access to sensitive data could indicate that an attacker has gained access to the system.
  5. An unusual increase in failed login attempts could indicate that an attacker is trying to guess a user’s password.

To test these hypotheses, a threat hunter might use a variety of tools and techniques, such as network traffic analysis, endpoint analysis, and log analysis, to gather more information and confirm or disprove the hypothesis.

  1. Identify the goal of the threat hunting exercise. This could be to find a specific type of malware, investigate a suspected intrusion, or something else.
  2. Gather information about the environment and assets that are being hunted. This could include data on network and system configurations, user behavior, and known threats.
  3. Identify potential sources of evidence that could support or refute the hypothesis. This could include log data, network traffic data, and other types of data that are relevant to the threat hunting scenario.
  4. Formulate a hypothesis that is specific, testable, and based on the available information. The hypothesis should clearly state what is being sought and how it is expected to manifest in the environment.
  5. Design a plan to test the hypothesis. This could include steps such as searching for specific indicators of compromise, analyzing network traffic data, or running simulations to see how the hypothesis plays out in the environment.
  6. Execute the plan and gather data to support or refute the hypothesis.
  7. Analyze the data and draw conclusions about the validity of the hypothesis. If the hypothesis is supported, take action to mitigate the threat. If the hypothesis is not supported, revise the hypothesis or design a new one based on the new information.

Sure! Here is a general process for creating a hypothesis for threat hunting:

  1. Identify the scope of the threat hunting effort. This could be a specific system or network, a particular type of threat or attack, or a specific time period.
  2. Gather intelligence on the threat or attack you are looking for. This could include information on known tactics, techniques, and procedures (TTPs) used by the threat actor, as well as indicators of compromise (IOCs) that may be associated with the threat.
  3. Formulate a hypothesis based on the intelligence gathered. The hypothesis should specify what you expect to find and why, based on the available evidence.
  4. Develop a plan to test the hypothesis. This should include specific steps and techniques you will use to gather evidence and verify or disprove the hypothesis.
  5. Execute the plan and collect evidence. This may involve analyzing log data, running scans and searches, or performing other investigative tasks.
  6. Evaluate the evidence and draw conclusions. Based on the evidence collected, determine whether the hypothesis was supported or refuted. If the hypothesis was supported, take appropriate action to mitigate the threat. If the hypothesis was not supported, consider refining the hypothesis and repeating the process.

Keep in mind that this is just a general outline, and the specific steps and techniques used will depend on the specifics of the threat hunting scenario.

Sure, here is a general process for creating a hypothesis for threat hunting:

  1. Identify the problem or question you are trying to solve: Before you can create a hypothesis, you need to clearly define the problem or question that you are trying to address. For example, you might be trying to identify a specific type of malware on your network, or you might be trying to determine if there has been unauthorized access to a specific system.
  2. Gather data: Next, you need to gather data that can be used to test your hypothesis. This could include logs, network traffic data, or other types of information that might provide clues about the threat you are hunting.
  3. Develop a hypothesis: Based on the data you have gathered and your understanding of the problem, come up with a hypothesis that explains what you think is happening. Your hypothesis should be a specific, testable prediction about the nature of the threat you are hunting.
  4. Test the hypothesis: Using the tools and techniques at your disposal, test your hypothesis to see if it holds up. This might involve running queries or analysis on the data you have collected, or it might involve conducting additional research or experimentation.
  5. Evaluate the results: Once you have tested your hypothesis, evaluate the results to see if they support your prediction. If the results support your hypothesis, then you can consider it to be a reasonable explanation for the problem or question you are trying to solve. If the results do not support your hypothesis, then you may need to go back to the drawing board and come up with a new hypothesis to test.

Sure! Here is a simple example of a hypothesis for threat hunting:

  1. Hypothesis: An attacker has compromised a network and is using a specific piece of malware to exfiltrate data.
  2. To test this hypothesis, the threat hunter could look for indicators of compromise (IOCs) associated with the suspected malware, such as specific file names or network traffic patterns. The threat hunter could also try to find evidence of the malware communicating with known command and control servers or attempting to access restricted data. If the threat hunter is able to find evidence supporting the hypothesis, they can then take steps to contain the threat and prevent further data exfiltration. If the hypothesis is not supported by the evidence, the threat hunter can revise their hypothesis and continue the investigation.

Sure, here is a sample hypothesis for a threat hunting scenario:

  1. Hypothesis: An attacker has compromised the network and is using a specific server as a pivot point to access other systems.
  2. Evidence: A sudden increase in network traffic to and from a particular server, with a high percentage of that traffic coming from unfamiliar IP addresses.
  3. Test: Collect and analyze additional network traffic data to see if the pattern of traffic to and from the suspect server continues. Use forensic tools to examine the server for signs of compromise, such as unusual processes or files.
  4. Expected outcome: If the hypothesis is correct, the additional data should show continued suspicious traffic patterns and evidence of compromise on the server. If the hypothesis is not correct, the additional data should not support the initial observations.

Sure, here is another sample hypothesis for a threat hunting scenario:

  1. Hypothesis: An attacker has gained access to a user’s account and is using it to exfiltrate sensitive data.
  2. Evidence: Unusual login activity from an unfamiliar location, followed by a sudden increase in data transfer from the user’s account.
  3. Test: Collect and analyze additional log data to see if the unusual login and data transfer activity can be traced back to a specific user account. Examine the user’s machine for signs of compromise, such as unusual processes or files.
  4. Expected outcome: If the hypothesis is correct, the additional data should show that the unusual activity can be traced back to a specific user account, and there should be evidence of compromise on the user’s machine. If the hypothesis is not correct, the additional data should not support the initial observations.

Certainly, here is another sample hypothesis for a threat hunting scenario:

  1. Hypothesis: An attacker has deployed malware on the network that is being used to conduct malicious activity.
  2. Evidence: An increase in network traffic to and from unfamiliar domains, along with an increase in the number of failed login attempts.
  3. Test: Collect and analyze network traffic data to identify the source of the traffic to and from the unfamiliar domains. Use forensic tools to examine the network for signs of malware, such as unusual processes or files.
  4. Expected outcome: If the hypothesis is correct, the additional data should show that the traffic to and from the unfamiliar domains is connected to the observed increase in failed login attempts, and there should be evidence of malware on the network. If the hypothesis is not correct, the additional data should not support the initial observations.

Sure, here is another sample hypothesis for a threat hunting scenario:

  1. Hypothesis: An attacker has gained access to a user’s account and is using it to send spam emails.
  2. Evidence: A sudden increase in the number of spam emails coming from a specific user’s account, with a high percentage of those emails being marked as spam by email filters.
  3. Test: Collect and analyze log data to see if the pattern of spam emails from the suspect account continues. Examine the user’s machine for signs of compromise, such as unusual processes or files.

Expected outcome: If the hypothesis is correct, the additional data should show that the suspect account is continuing to send a high volume of spam emails. If the hypothesis is not correct, the additional data should not support the initial observations.

Sure, here is another sample hypothesis for a threat hunting scenario:

  1. Hypothesis: An attacker has deployed malware on the network that is being used to conduct denial of service attacks.
  2. Evidence: An increase in network traffic to and from unfamiliar domains, along with a decrease in network performance and availability.
  3. Test: Collect and analyze network traffic data to identify the source of the traffic to and from the unfamiliar domains. Use forensic tools to examine the network for signs of malware, such as unusual processes or files.
  4. Expected outcome: If the hypothesis is correct, the additional data should show that the traffic to and from the unfamiliar domains is connected to the observed decrease in network performance and availability, and there should be evidence of malware on the network. If the hypothesis is not correct, the additional data should not support the initial observations.
  5. Certainly, here is another sample hypothesis for a threat hunting scenario:
  6. Hypothesis: An attacker has gained access to the network and is using a specific user account to send phishing emails.
  7. Evidence: A sudden increase in the number of phishing emails coming from a specific user’s account, with a high percentage of those emails being marked as spam by email filters.
  8. Test: Collect and analyze log data to see if the pattern of phishing emails from the suspect account continues. Examine the user’s machine for signs of compromise, such as unusual processes or files.
  9. Expected outcome: If the hypothesis is correct, the additional data should show that the suspect account is continuing to send a high volume of phishing emails. If the hypothesis is not correct, the additional data should not support the initial observations.

Sure, here is another sample hypothesis for a threat hunting scenario:

  1. Hypothesis: An attacker has gained access to a user’s account and is using it to access sensitive data and perform unauthorized actions.
  2. Evidence: Unusual login activity from an unfamiliar location, followed by suspicious actions taken within the user’s account, such as accessing sensitive data or performing unauthorized actions.
  3. Test: Collect and analyze log data to see if the unusual login and suspicious actions can be traced back to a specific user account. Examine the user’s machine for signs of compromise, such as unusual processes or files.
  4. Expected outcome: If the hypothesis is correct, the additional data should show that the unusual login and suspicious actions can be traced back to a specific user account, and there should be evidence of compromise on the user’s machine. If the hypothesis is not correct, the additional data should not support the initial observations.

Sure, here is another sample hypothesis for a threat hunting scenario:

  1. Hypothesis: An attacker has gained access to the network and is using it to conduct cryptocurrency mining.
  2. Evidence: An increase in network traffic to and from unfamiliar domains, along with an increase in network resource usage, such as high CPU or memory usage.
  3. Test: Collect and analyze network traffic data to identify the source of the traffic to and from the unfamiliar domains. Use forensic tools to examine the network for signs of cryptocurrency mining activity, such as unusual processes or files.
  4. Expected outcome: If the hypothesis is correct, the additional data should show that the traffic to and from the unfamiliar domains is connected to the observed increase in network resource usage, and there should be evidence of cryptocurrency mining activity on the network. If the hypothesis is not correct, the additional data should not support the initial observations.

Sure, here is another sample hypothesis for a threat hunting scenario:

Hypothesis: An attacker has gained access to a user’s account and is using it to perform unauthorized actions, such as transferring funds or making purchases.

Evidence: Unusual login activity from an unfamiliar location, followed by reports of unauthorized actions being taken within the user’s account.

Test: Collect and analyze log data to see if the unusual login and unauthorized actions can be traced back to a specific user account. Examine the user’s machine for signs of compromise, such as unusual processes or files.

Expected outcome: If the hypothesis is correct, the additional data should show that the unusual login and unauthorized actions can be traced back to a specific user account, and there should be evidence of compromise on the user’s machine. If the hypothesis is not correct, the additional data should not support the initial observations.

Hypothesis: An attacker has compromised a system on the network and is using it to exfiltrate sensitive data.

To test this hypothesis, a threat hunter could look for indicators of compromise (IOCs) such as unusual network traffic patterns, newly created accounts with elevated privileges, or suspicious processes running on the system in question. The hunter could also use forensic tools to examine the system and search for evidence of malware or other malicious activity. If the hunter is able to find evidence that supports the hypothesis, they can then work to isolate and remediate the compromise. If the hypothesis is not supported by the evidence, the hunter may need to revise their hypothesis and continue the investigation.

Sure! A hypothesis is an educated guess or prediction about a particular phenomenon that can be tested through further investigation. In the context of threat hunting, a hypothesis might be a potential explanation for an observed security incident or an assumption about the behavior of an advanced persistent threat (APT) group. Here are a few examples of hypotheses that could be relevant in threat hunting scenarios:

  1. The intrusion we observed was likely carried out by a state-sponsored APT group because of the highly targeted nature of the attack and the use of sophisticated malware.
  2. The malware sample we found on one of our systems is likely part of a larger campaign because it contains a similar codebase to other samples that have been linked to a known APT group.
  3. The network traffic patterns we’ve observed suggest that there may be an unauthorized device connected to our network, potentially for the purpose of exfiltrating data.
  4. An employee’s account was compromised, and the attacker is using it to pivot to other systems within our network.
  5. A recent update to a commonly used application introduced a vulnerability that is being exploited by attackers.

Keep in mind that a hypothesis is just a starting point for further investigation, and it should be tested through additional analysis and data gathering before it can be considered a confirmed explanation.

6. A malicious actor has gained access to our network and is using it as a staging ground to launch attacks against other organizations.

Hypothesis: An attacker has gained access to the network and is using it as a staging ground to launch attacks against other organizations.

Evidence: Reports of suspicious activity on the network, such as unusual network traffic or the presence of malware, and indicators that the network is being used to launch attacks against other organizations.

Test: Collect and analyze log data, network traffic data, and other relevant information to identify the source of the suspicious activity and any connections to attacks against other organizations. Use forensic tools to examine the network for signs of compromise, such as unusual processes or files.

Expected outcome: If the hypothesis is correct, the additional data should show that the network is being used as a staging ground for attacks against other organizations, and there should be evidence of compromise on the network. If the hypothesis is not correct, the additional data should not support the initial observations.

7. A new piece of malware has been introduced to our network, and it is currently in the process of propagating itself to other systems.

Hypothesis: A new piece of malware has been introduced to the network, and it is currently in the process of propagating itself to other systems.

Evidence: Reports of a new piece of malware on the network, along with indicators that the malware is attempting to spread to other systems, such as increased network traffic or the presence of unusual processes or files.

Test: Collect and analyze log data, network traffic data, and other relevant information to identify the source of the malware and its behavior on the network. Use forensic tools to examine the network for signs of the malware, such as unusual processes or files.

Expected outcome: If the hypothesis is correct, the additional data should show the presence of the new malware on the network and its attempts to propagate to other systems. If the hypothesis is not correct, the additional data should not support the initial observations.

8. A user’s account is being used to conduct suspicious activity, indicating that it may have been compromised.

Hypothesis: A user’s account has been compromised and is being used to conduct suspicious activity.

Evidence: Reports of suspicious activity within a specific user’s account, such as unusual login activity or unauthorized actions.

Test: Collect and analyze log data to see if the suspicious activity can be traced back to the user’s account and if there are any indicators of compromise, such as unusual processes or files on the user’s machine.

Expected outcome: If the hypothesis is correct, the additional data should show that the suspicious activity can be traced back to the user’s account and that there are indicators of compromise on the user’s machine. If the hypothesis is not correct, the additional data should not support the initial observations.

9. A recent update to one of our systems introduced a vulnerability that is being actively exploited by attackers.

Hypothesis: A recent update to one of our systems introduced a vulnerability that is being actively exploited by attackers.

Evidence: Reports of a recent update to a specific system, along with indicators that the system is being actively exploited, such as unusual network traffic or the presence of malware.

Test: Collect and analyze log data, network traffic data, and other relevant information to identify the source of the exploitation and any indicators of compromise on the system, such as unusual processes or files.

Expected outcome: If the hypothesis is correct, the additional data should show that the system is being actively exploited and that there are indicators of compromise on the system. If the hypothesis is not correct, the additional data should not support the initial observations.

10. An APT group is using a previously unknown zero-day vulnerability to compromise our systems.

Hypothesis: An APT group is using a previously unknown zero-day vulnerability to compromise our systems.

Evidence: Reports of a previously unknown vulnerability being exploited, along with indicators that an APT group is responsible, such as a specific modus operandi or tools being used.

Test: Collect and analyze log data, network traffic data, and other relevant information to identify the source of the exploitation and any indicators of compromise on the system, such as unusual processes or files.

Expected outcome: If the hypothesis is correct, the additional data should show that the systems are being compromised through the use of a previously unknown zero-day vulnerability, and that an APT group is responsible. If the hypothesis is not correct, the additional data should not support the initial observations.

11. A new variant of a known malware strain has been introduced to our network, and it is exhibiting behavior that is different from previous versions.

Hypothesis: A new variant of a known malware strain has been introduced to the network, and it is exhibiting behavior that is different from previous versions.

Evidence: Reports of a new variant of a known malware strain on the network, along with indicators that the variant is exhibiting different behavior, such as different network traffic patterns or the presence of unusual processes or files.

Test: Collect and analyze log data, network traffic data, and other relevant information to identify the source of the new variant and its behavior on the network. Use forensic tools to examine the network for signs of the malware, such as unusual processes or files.

Expected outcome: If the hypothesis is correct, the additional data should show the presence of the new variant of the known malware strain on the network and its different behavior compared to previous versions. If the hypothesis is not correct, the additional data should not support the initial observations.

12. A malicious actor is using an insider’s account to exfiltrate data from our organization.

Hypothesis: An insider’s account has been compromised and is being used by a malicious actor to exfiltrate data from the organization.

Evidence: Reports of suspicious activity within a specific user’s account, such as unusual login activity or unauthorized data transfer, and indicators that an outsider may be responsible, such as login activity from unfamiliar locations.

Test: Collect and analyze log data to see if the suspicious activity can be traced back to the user’s account and if there are any indicators of compromise, such as unusual processes or files on the user’s machine.

Expected outcome: If the hypothesis is correct, the additional data should show that the suspicious activity can be traced back to the user’s account and that there are indicators of compromise on the user’s machine, suggesting that an outsider has gained access to the account. If the hypothesis is not correct, the additional data should not support the initial observations.

13. A group of compromised systems within our network are communicating with a known command and control server, indicating the presence of a coordinated attack.

Hypothesis: A group of compromised systems within the network are communicating with a known command and control server, indicating the presence of a coordinated attack.

Evidence: Reports of compromised systems on the network and indicators that those systems are communicating with a known command and control server, such as unusual network traffic to and from the server.

Test: Collect and analyze log data, network traffic data, and other relevant information to identify the compromised systems and their communication with the known command and control server. Use forensic tools to examine the systems for signs of compromise, such as unusual processes or files.

Expected outcome: If the hypothesis is correct, the additional data should show that the compromised systems are communicating with the known command and control server, indicating the presence of a coordinated attack. If the hypothesis is not correct, the additional data should not support the initial observations.

14. A user’s account is being used to access sensitive data that it does not normally have access to, indicating that the account may have been compromised.

Hypothesis: A user’s account has been compromised and is being used to access sensitive data that the account does not normally have access to.

Evidence: Reports of a specific user’s account accessing sensitive data that it does not normally have access to, along with indicators that the account may have been compromised, such as unusual login activity or the presence of unusual processes or files on the user’s machine.

Test: Collect and analyze log data to see if the access to sensitive data can be traced back to the user’s account and if there are any indicators of compromise, such as unusual processes or files on the user’s machine.

Expected outcome: If the hypothesis is correct, the additional data should show that the access to sensitive data can be traced back to the user’s account and that there are indicators of compromise on the user’s machine. If the hypothesis is not correct, the additional data should not support the initial observations.

15. A new, previously unknown APT group is using a novel technique to compromise our systems.

Hypothesis: A new, previously unknown APT group is using a novel technique to compromise our systems.

Evidence: Reports of a new APT group on the network and indicators that the group is using a novel technique to compromise systems, such as unusual network traffic patterns or the presence of unknown malware.

Test: Collect and analyze log data, network traffic data, and other relevant information to identify the new APT group and their technique for compromising systems. Use forensic tools to examine the network for signs of the group’s activity, such as unusual processes or files.

Expected outcome: If the hypothesis is correct, the additional data should show the presence of the new APT group on the network and their use of a novel technique to compromise systems. If the hypothesis is not correct, the additional data should not support the initial observations.

16. A malicious actor has gained access to our network and is using it as a staging ground to launch attacks against other organizations.

Hypothesis: An attacker has gained access to the network and is using it as a staging ground to launch attacks against other organizations.

Evidence: Reports of suspicious activity on the network, such as unusual network traffic or the presence of malware, and indicators that the network is being used to launch attacks against other organizations.

Test: Collect and analyze log data, network traffic data, and other relevant information to identify the source of the suspicious activity and any connections to attacks against other organizations. Use forensic tools to examine the network for signs of compromise, such as unusual processes or files.

Expected outcome: If the hypothesis is correct, the additional data should show that the network is being used as a staging ground for attacks against other organizations, and there should be evidence of compromise on the network. If the hypothesis is not correct, the additional data should not support the initial observations.

17. A recent phishing campaign has resulted in a number of compromised accounts, which are being used to pivot to other systems within our network.

Here is a sample hypothesis based on the information provided:

Hypothesis: An attacker has gained access to a number of user accounts through a phishing campaign, and is using those accounts to pivot to other systems within the network.

Evidence: Reports of a recent phishing campaign, along with compromised user accounts and suspicious activity on those accounts, such as unusual login activity or data transfer.

Test: Collect and analyze log data to see if the compromised accounts can be traced back to the phishing campaign and if there is any suspicious activity on those accounts beyond the initial compromise. Examine the affected user’s machines for signs of compromise, such as unusual processes or files.

Expected outcome: If the hypothesis is correct, the additional data should show that the compromised accounts can be traced back to the phishing campaign and that there is suspicious activity on those accounts beyond the initial compromise, such as attempts to pivot to other systems. If the hypothesis is not correct, the additional data should not support the initial observations.

18. A group of systems within our network are communicating with known malicious IP addresses, indicating the presence of malware.

Hypothesis: A group of systems within the network are communicating with known malicious IP addresses, indicating the presence of malware.

Evidence: Reports of systems on the network communicating with known malicious IP addresses, along with indicators that the systems may be compromised, such as unusual network traffic or the presence of unusual processes or files.

Test: Collect and analyze log data, network traffic data, and other relevant information to identify the systems communicating with the known malicious IP addresses and any indicators of compromise on those systems, such as unusual processes or files.

Expected outcome: If the hypothesis is correct, the additional data should show that the systems are communicating with the known malicious IP addresses and that there are indicators of compromise on those systems. If the hypothesis is not correct, the additional data should not support the initial observations.

19. A piece of malware has been introduced to our network that is designed to evade detection by traditional security tools.

Hypothesis: A piece of malware has been introduced to the network that is designed to evade detection by traditional security tools.

Evidence: Reports of malware on the network that is designed to evade detection, along with indicators that the malware may have successfully evaded detection, such as a lack of detections by traditional security tools.

Test: Collect and analyze log data, network traffic data, and other relevant information to identify the presence and behavior of the malware on the network. Use specialized tools or techniques, such as forensic analysis or sandboxing, to detect the malware and analyze its behavior.

Expected outcome: If the hypothesis is correct, the additional data should show the presence of the malware on the network and its attempts to evade detection. If the hypothesis is not correct, the additional data should not support the initial observations.

20. A malicious actor has gained access to a high-level employee’s account and is using it to conduct targeted attacks against other organizations.

Hypothesis: A malicious actor has gained access to a high-level employee’s account and is using it to conduct targeted attacks against other organizations.

Evidence: Reports of suspicious activity within a specific high-level employee’s account, such as unusual login activity or unauthorized actions, and indicators that the account is being used to conduct targeted attacks against other organizations.

Test: Collect and analyze log data to see if the suspicious activity can be traced back to the employee’s account and if there are any indicators of compromise, such as unusual processes or files on the employee’s machine.

Expected outcome: If the hypothesis is correct, the additional data should show that the suspicious activity can be traced back to the employee’s account and that there are indicators of compromise on the employee’s machine, suggesting that the account has been compromised and is being used to conduct targeted attacks against other organizations. If the hypothesis is not correct, the additional data should not support the initial observations.

21. A new APT group is using a previously unknown method to compromise our systems.

Hypothesis: A new APT group is using a previously unknown method to compromise our systems.

Evidence: Reports of a new APT group on the network and indicators that the group is using a previously unknown method to compromise systems, such as unusual network traffic patterns or the presence of unknown malware.

Test: Collect and analyze log data, network traffic data, and other relevant information to identify the new APT group and their method for compromising systems. Use forensic tools to examine the network for signs of the group’s activity, such as unusual processes or files.

Expected outcome: If the hypothesis is correct, the additional data should show the presence of the new APT group on the network and their use of a previously unknown method to compromise systems. If the hypothesis is not correct, the additional data should not support the initial observations.

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