Login
Digital Forensics: Investigating a Ransomware Attack
Welcome back, aspiring forensic investigators!
We continue our practical series on digital forensics and will look at the memory dump of a Windows machine after a ransomware attack. Ransomware incidents are common, although they may not always be the most profitable attacks because they require a lot of effort and stealth. Some operations take months of hard work and sleepless nights and still never pay off. Many attackers prefer to steal data and sell it on the dark web. Such data sells well and quickly. State sponsored APTs act similarly. Their goal is to stay silent and extract as much intelligence as possible.
Today, a thousand unique entries of private information of Russian citizens cost about $100. That’s cheap. But it also shows how effective Ukrainian and foreign hackers are against Russia. All this raises demand for digital forensics and incident response, since fines for data leaks can be enormous. It’s not only fines that are a threat. Reputation damage is critical. If your competitor has never, at least yet, experienced a data breach and you did and it went public, trust in your company will start crumbling and customers will be inclined to use your competitors’ services. An even worse scenario is a ransomware attack that locks down much of your organization and wipes out your backups. Paying the attackers gives no guarantee of recovering your data, and some companies never manage to recover at all.
So let’s investigate one of those attacks and learn something new to stay sharp.
Memory Analysis
It all begins with a memory dump. Here we already have a memory dump file of an infected machine that we are going to inspect.
Installing Volatility
On our Kali machine we created a new Python virtual environment for Volatility. Keeping separate environments is good practice because it prevents tools from interfering with other dependencies. Sometimes installing one tool can break another. Here is how you do it:
bash$ > python3 -m venv env_name
bash$ > source env_name/bin/activate
Now we are ready to install Volatility in this environment:
bash$ > pip3 install volatility3
It is also good practice to record the exact versions of Volatility and Python you used (for example, pip3 show volatility3 and python3 --version). Memory forensics tools change over time and some plugins behave slightly differently between releases. Recording versions makes your work reproducible later.
Image Information
One of the first things we look at after receiving a memory dump is the captured metadata. The Volatility 3 command is simple:
bash$ vol -f infected.vmem windows.info
When you run windows.info, inspect the OS build, memory size, and timestamps shown by the capture tool. That OS build value helps Volatility pick the correct symbol tables. Incorrect symbols can cause missing or malformed output. This is especially important if you are working with Volatility 2. Also confirm the capture method and metadata such as who made the capture, when, and whether the capture was acquired after isolating the machine. Recording this chain-of-custody metadata is a small step that greatly strengthens any forensic report.
Processes
The goal of the memory dump is to preserve processes, injections, and shellcode before they disappear after a reboot. That means we need to focus on the processes that existed at capture time. Let’s list them all:
bash$ > vol -f infected.vmem windows.pslist
Suspicious processes are not always easy to spot. It depends on the attacker’s tactics. Ransomware processes, unlike persistence mechanisms, are often obvious because attackers tend to pick violent or alarming names for encryptors. But that’s not always the case, so let’s give our image a closer look.
Among other processes, a ransomware process sticks out. You may also notice or4qtckT.exe and other processes with unknown names. Random executable names are not definitive proof of maliciousness, but they’re a reliable starting point for closer inspection. Some legitimate software may also generate processes with random names, for example, Dr.Web, a Russian antivirus.
When a process name looks random, check several things: the process parent, the process start time (did it start right before the incident?), open network sockets, loaded DLLs, and whether the executable exists on disk or only in memory. Processes that only exist in the RAM image (no matching file on disk) often indicate in-memory unpacking or fileless behavior. These are important signals in malware analysis. Use plugins like windows.psscan (process scan) to find processes that pslist might miss and windows.pstree to visualize parent/child relationships. Also check windows.dlllist to see suspicious DLLs loaded into a process. Injected code often pulls suspicious DLL names or shows unnatural memory protections on executable pages.
Parent Relationships
Once you find malware, your next step is to find its parent. A parent is the process that launches another process. This is how you unravel the attack by going back in the timeline. windows.pslist has two important columns: PID (process ID) and PPID (parent process ID). The parent of WanaDecryptor has PID 2732. We can quickly search and find it.
Now we know that the process with a random name or4qtckT.exe initiated WanaDecryptor. As it might not be the only process initiated by that parent, let’s grep its PID and find out:
bash$ > vol -f infected.vmem windows.psscan | grep 2732
The parent process can show how the attacker entered the machine. It might be a user process opened by a phishing email, a scheduled task that ran at an odd hour, or a system service that got abused. Tracing parents helps you decide whether this was an interactive compromise (an attacker manually ran something) or an automated spread. If you see network-facing services as parents or child processes that match known service names (for example, svchost.exe variants), dig deeper. Some ransomware uses service abuse, scheduled tasks, or built-in Windows mechanisms to reach higher privileges or persistence.
Handles
In Windows forensics, when we say we are “viewing the handles of a process,” we mean examining the internal references that a process has opened to system resources. A handle in Windows is essentially a unique identifier (a number) that a process uses to access an operating system object. Processes do not work directly with raw resources like files, registry keys, threads, or network connections. Instead, when a process needs access to something, it asks Windows to open that object, and Windows returns a handle. That handle acts like a ticket which the process can use to interact with the object safely.
bash$ > vol -f infected.vmem windows.handles --pid 2732
First, we see a user (hacker) directory. That should be noted for further analysis, because user directories contain useful evidence in NTUSER.DAT and USRCLASS.DAT. These objects can be accessed after a full disk capture and will include thorough information about shares, directories, and objects the user accessed.
Inspecting the handles, we found an .eky file that was used to encrypt the system
This .eky file contains the secret the attacker needed to lock files on the system. These keys are brought from the outside and are not native system objects. Obtaining this key does not guarantee successful decryption. It depends on what kind of key file it is and how it was protected.
When you find cryptographic artifacts in handles, copy the file bytes, if possible, and get the hashes (SHA-256) before touching them. Export them into an isolated analysis workstation. Then compare the artifact to public resources and sandbox reports. Not every key-like file is the private key you need to decrypt. Sometimes attackers include only a portion or an encrypted container that requires an additional password or remote secret. Public repositories and collective projects (for example, NoMoreRansom and vendor decryptors) may already have decryption tools for some ransomware families, so check there before calling data irrecoverable.
Command Line
Now let’s inspect the command lines of the processes. Listing all command lines gives you more visibility to spot malicious behavior:
bash$ > vol -f infected.vmem windows.cmdline
You can also narrow it down to the needed PIDs or file names:
bash$ > vol -f infected.vmem windows.cmdline | grep or4
We can now see where the attack originated. After a successful compromise of a system or a domain, the attacker brought their malware to the system and encrypted it with their own keys.
The command line often contains the exact flags or network locations the attacker used (for example, -server 192.168.x.x or a path to an unpacker). Attackers sometimes use command-line switches to hide behavior, choose a configuration file, or provide a URL to download further payloads. If you can capture the command line, you often capture the attacker’s intent in plain text, which is invaluable evidence. Also check process environment variables, if those are available, because they might contain temporary filenames, credentials, or proxy settings the malware used.
Getting Hashes
Obviously the investigation does not stop here. You need to extract the file from memory, calculate its hash, and inspect how the malware behaves on AnyRun, VirusTotal, and other platforms. To extract the malware we first need to find its address in memory:
bash$ > vol -f infected.vmem windows.file | grep -i or4qtckT
Let’s pick the second hit and extract it now:
bash$ > vol -f infected.vmem windows.dumpfiles --physaddr 0x1fcaf798
The ImageSection dump (.img) usually looks like the program that was running in memory. It can include changes made while the program was loaded, such as unpacked code or adjusted memory addresses. The DataSection dump (.dat), on the other hand, shows what the file looks like on disk, or at least part of it. That’s why there are two dumps with the same name. Volatility detected both the in-memory version and the on-disk version of or4qtckT.exe
Next we generate the hash of the DataSectionObject and look it up on VirusTotal:
bash$ > sha256sum file.0x1fcaf798.0x85553db8.DataSectionObject.or4qtckT.exe.dat
We recommend using robust hashing (SHA-256 instead of MD5) to avoid collision issues.
For more information, go to Hybrid Analysis to get a detailed report on the malware’s capabilities.
Some platforms like VirusTotal, AnyRun, Hybrid Analysis, Joe Sandbox will produce behavioral reports, network traffic captures, and dropped files that help you map capabilities like network C2, persistence techniques, and whether the sample attempts to self-propagate. In our case, this sample has been found in online sandbox reports and is flagged with ransomware/WannaCry-like behavior. Sandbox summaries showed malicious activity consistent with file encryption and automated spread. When reading sandbox output, focus on three things: dropped files, outbound connections, and any use of legacy Windows features (SMB, WMI, PsExec) to move laterally.
Practical next steps for the investigator
First, preserve the memory image and any extracted files exactly as you found them. Do not run suspicious samples on your analysis workstation unless it is fully isolated. Second, gather network indicators (IP addresses, domain names) and add them to your blocklists and detection rules. Third, check for related persistence mechanisms on disk and in registry hives, if you have the disk image. Scheduled tasks, HKLM\Software\Microsoft\Windows\CurrentVersion\Run entries, service modifications, and driver loads are common. Fourth, feed the sample hash and any dropped files into public repositories and vendor sandboxes. These can help you find other victims and understand the campaign’s breadth. Finally, document everything, every command and every timestamp, so you can later show how the evidence was acquired, processed, and analyzed. For memory-specific checks, run Volatility plugins such as malfind (detect injection), ldrmodules (module loads), dlllist, netscan (network sockets), and registry plugins to inspect in-memory registry hives.
Summary
Think of memory as the attacker’s black box. It often holds the fleeting traces disk images miss, things like unpacked code, live network sockets, and cryptographic keys. Prioritizing memory first allows you to catch those traces before they’re gone. Volatility can help you list running processes, trace parent–child chains, inspect handles and command lines. You can also dump in-memory binaries and use them as artifacts for a more thorough analysis. Submitting these artifacts to sandboxes will give you a clear picture of what happened on your network, which will give you valuable IOCs to prevent this attack and techniques used. As a forensic analyst you are required to preserve the image intact, work with suspicious files in an isolated lab, and write down every command and timestamp to keep the chain of custody reliable and actions repeatable.
If you need forensic assistance, we offer professional services to help investigate and mitigate incidents. Additionally, we provide classes on digital forensics for those looking to expand their skills and understanding in this field.
For more Memory Forensics, check out our upcoming Memory Forensics class.
The post Digital Forensics: Investigating a Ransomware Attack first appeared on Hackers Arise.
