Episode 39 — Turn Attacker Behavior into Clear Notes with Adversary Analysis Methods
In this episode, we’re going to practice a skill that separates vague security thinking from useful security thinking: turning messy attacker activity into clear, organized notes. When an intrusion happens, you rarely get a neat story handed to you. You get fragments, like an unusual login here, a suspicious process there, and an unexpected network connection somewhere else. Adversary analysis is the method of assembling those fragments into a coherent explanation of what the attacker did, why they did it, and what they might do next. The notes you take matter because they become the bridge between detection, response, and learning. If your notes are unclear, teams waste time arguing about what happened. If your notes are clear, teams can act quickly, contain impact, and improve defenses. The beginner goal is not to become a professional incident responder overnight, but to learn a simple, repeatable way to describe attacker behavior without getting lost in jargon.
Before we continue, a quick note: this audio course is a companion to our course companion books. The first book is about the exam and provides detailed information on how to pass it best. The second book is a Kindle-only eBook that contains 1,000 flashcards that can be used on your mobile device or Kindle. Check them both out at Cyber Author dot me, in the Bare Metal Study Guides Series.
Start with the idea that good adversary notes are behavioral, not emotional. Instead of writing that an attacker was sophisticated or sneaky, you write what they actually did and what evidence suggests it. The most useful notes separate facts from interpretation. Facts are things you can point to, such as a login from a certain location, a process start, or a connection to a destination. Interpretation is what you think those facts mean, such as credential theft or persistence. Both are important, but mixing them can confuse readers. A simple habit is to write the observable event first, then add a short interpretation statement that is clearly labeled as your assessment. This makes it easier for others to validate your reasoning and reduces the chance that assumptions become treated as certainty. In adversary analysis, clarity beats cleverness every time.
A practical way to structure notes is to think in terms of a timeline. Attackers act in sequences, and sequences create cause-and-effect relationships. If you capture events in order, the story becomes easier to understand. Start your timeline with the earliest known point, which might be recon activity, a phishing email, or a login event, and then list what happened next. Each entry should include a time reference, what happened, where it happened, and how you know. For example, you might note that a user account authenticated from an unusual location and that this was observed in authentication logs. Then you might note that shortly after, the same account attempted access to a sensitive application and that this was observed in application logs. The timeline becomes a narrative backbone that keeps your analysis grounded. Even if some timestamps are missing or uncertain, having an ordered list is still better than a pile of unconnected details.
Another useful method is to organize notes around attacker goals, because attacker behavior is often goal-driven. An attacker who has gained initial access usually needs to accomplish certain things to be effective. They may need to establish persistence, obtain credentials, discover the environment, move laterally, and locate valuable data. If you categorize events by goal, you can see patterns more quickly. For example, repeated access to credential stores suggests credential harvesting, while creation of scheduled tasks suggests persistence. Network scanning behavior suggests internal reconnaissance. Large file access suggests collection or staging. You do not need to know every technique name to do this; you just need to ask what the attacker was trying to achieve with each action. When you can tie a behavior to a likely goal, your notes become more predictive because they help you anticipate next steps.
A third method is to describe each action using a simple sentence template. One effective template is subject, action, object, and result. The subject is the actor, such as a user account, a host, or a process. The action is what occurred, such as authenticated, executed, wrote, connected, or modified. The object is what was acted upon, such as a server, a file share, a registry setting, or an external destination. The result is the outcome or suspicion, such as access obtained, persistence established, or data accessed. This template forces specificity. Instead of writing that malware did something, you write that a process on a host created a new scheduled task that runs at startup. That sentence is far more useful because it can be validated, investigated, and mitigated. Beginners often write vague notes because they are not sure what matters, but specificity is what makes notes actionable.
Adversary analysis also benefits from linking related events into short hypotheses. A hypothesis is a best explanation for a cluster of observations. For example, you might observe a phishing email, followed by an unusual login, followed by M F A prompt fatigue behavior, followed by new outbound connections. A reasonable hypothesis is that credentials were phished, M F A was bypassed through user approval, and a foothold established C 2. The hypothesis should be testable, meaning you can look for more evidence to confirm or disprove it. Testability matters because early analysis often includes uncertainty. You want notes that guide what to check next rather than notes that claim certainty without support. A well-written hypothesis is a compass, not a verdict. It points you toward next evidence collection steps and containment priorities.
One important part of good notes is capturing scope. Scope is the set of systems, accounts, and data that might be affected. Beginners sometimes focus only on the first compromised device and forget that attackers often pivot. Your notes should track which accounts were used, which hosts were accessed, and which resources were touched. Even if you do not know the full scope yet, you can list what is confirmed and what is suspected. For example, you might state that a specific user account authenticated to a specific service and that the same account attempted access to another system. You might note which devices show signs of persistence changes and which do not. Scope notes help teams prioritize response actions like disabling accounts, isolating hosts, and reviewing data access. Without scope, response becomes guesswork, and missed scope is how intrusions linger.
It is also valuable to capture how the attacker’s behavior aligns with normal versus abnormal patterns. Attackers often try to blend in by using normal tools and valid credentials. That means that a single action, like a login, may not look suspicious by itself. What makes it suspicious is context and sequence. Your notes should capture those contextual mismatches, such as a user accessing a system they never use, an administrative action performed at an unusual time, or a workstation initiating connections normally seen only from servers. Writing this context helps others understand why you flagged the event. It also makes your notes more educational for future prevention because it highlights what normal should have been. Over time, these observations can feed into better detection rules and access policies.
As you take notes, you should also capture the defensive clues and control failures that made the attacker’s actions possible. For example, if a successful login occurred without M F A, note that M F A was not enforced for that access path. If a vulnerable web service was exploited, note that the service was exposed and unpatched. If a misconfiguration allowed public access, note the policy setting that caused exposure. This is not about blame; it is about learning. Good adversary analysis does not stop at describing attacker actions. It connects actions to enabling conditions so defenses can be improved. If you can identify the enabling condition, you can often prevent similar behavior in the future. Beginners should practice writing at least one sentence about why a step worked, not just what happened.
There is also a communication aspect to note-taking, because your notes must be readable by people who were not watching the event unfold. That means avoiding overly dense jargon and being consistent with terminology. Use the same names for the same systems and accounts throughout your notes. If you are not sure about something, say so clearly, and label it as suspected rather than confirmed. Include enough detail that someone can follow your reasoning without needing your personal memory. This is especially important because incident response often involves handoffs across teams and time zones. Clear notes reduce friction and prevent repeated work. For beginners, remember that your notes are not just for you; they are a shared artifact that enables coordinated action.
A common misconception is that adversary analysis is only about mapping attackers to named groups. While attribution can matter in some contexts, it is usually not the first priority during early analysis. Early priority is understanding what happened, what is affected, and what to do next. Another misconception is that you need a perfect dataset to start analysis. In reality, you start with what you have and update as you learn more. Notes should be living documents that evolve, not static reports written after everything is finished. You also do not need to know every framework to take good notes. Frameworks can help organize thinking, but the core skill is disciplined observation and clear writing. If your notes enable action and learning, they are doing their job.
To make this skill stick, practice a simple rhythm whenever you describe an intrusion. First, list observable events in time order. Second, group events by likely attacker goals such as initial access, persistence, credential access, discovery, lateral movement, and data access. Third, write one or two hypotheses that explain clusters of events and that suggest what to check next. Fourth, capture scope and confidence, clearly separating confirmed from suspected. Fifth, note enabling conditions and potential improvements. This rhythm turns chaos into structure. It also creates a consistent style that others can follow, which is important in team environments. Over time, repeating this rhythm makes your analysis faster and more reliable.
In conclusion, adversary analysis methods help you turn attacker behavior into clear notes by organizing evidence, building timelines, and connecting actions to goals and enabling conditions. Good notes separate facts from interpretation, use specific language that can be validated, and track scope across accounts, hosts, and data. Hypotheses help you explain clusters of observations while remaining testable and open to refinement. Context explains why events are suspicious and helps future defenses improve. The decision rule to remember is this: if you cannot state an attacker action as a specific subject, action, and object supported by an observable source, rewrite the note until it becomes precise enough to guide investigation and response.
