Netskope Threat Coverage: WhisperGate
By Gustavo Palazolo
Published: 2022-01-26 · Archived: 2026-04-02 11:18:12 UTC
Summary
A new destructive malware called WhisperGate was discovered in mid-January 2022 targeting Ukrainian
organizations. This threat emerged during geopolitical conflicts in Ukraine, masquerading as ransomware.
However, this malware has a more destructive nature: wiping files and corrupting disks to prevent the OS from
loading. Ukraine has suffered other cyberattacks that seem to be connected to WhisperGate, such as the
defacement of many websites connected to their governments.
This is a multi-stage malware, where one of the payloads is hosted on a Discord server. The preference of
attackers to use cloud services for malicious purposes is increasingly common, as pointed out in an analysis of a
threat campaign that uses multiple cloud services throughout the attack. The threat group behind WhisperGate is
being tracked as DEV-0586, and so far there isn’t any association between this attack to known APT groups. In
this threat coverage, we analyzed all four stages of WhisperGate to demonstrate how it works.
Analysis
Stage 01
WhisperGate’s first stage is a small executable compiled with MinGW, responsible for corrupting the disk by
writing code into the Master Boot Record (MBR), which is a small section on disk that contains the Partition
Table and an executable code related to the boot loader.
Binary information about WhisperGate’s first stage
Corrupting the MBR is a simple technique to prevent any Operating System from loading, as the assembly code is
executed before the OS.
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The entire code for the first stage of WhisperGate can fit in a single screenshot, where the malware loads the MBR
data that will be written to disk, opens a handle to the physical drive with CreateFileW, and uses WriteFile to
writes the 512 bytes to MBR, which is located in the first sector of the disk.
Disassembled code of WhisperGate’s first stage.
The MBR stub written to disk includes a 16-bit assembly code and a message.
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Data written on disk by WhisperGate
If we load this data into the disassembler, we can analyze the 16-bit assembly that will be executed once the
computer is rebooted, which doesn’t do anything but display a message.
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Code that is executed once the computer is infected with WhisperGate.
Once the computer is infected, as soon as it restarts, the message is displayed and the OS is prevented from
loading. The message says the hard drive was corrupted and demands a payment of $10,000 via Bitcoin to a
specific walled address.
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Computer infected with the first stage of WhisperGate.
This is the only action performed by the first stage of WhisperGate. The following stages were created probably to
add a certain resilience to the attack in case the first stage fails, as systems may use GUID Partition Table (GPD),
which is MBR’s successor.
Stage 02
In this stage, we have a simple .NET downloader for stage 03. The binary contains an expired signature from
Microsoft, and although it is not shown by identification tools, the file is obfuscated with NetReactor, as pointed
out by OALabs.
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Binary information about WhisperGate’s second stage.
Once running, it downloads the third stage from a Discord server, named “Tbopbh.jpg”.
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WhisperGate’s .NET downloader.
After the download, the malware loads the binary as a .NET assembly and executes the method named
“Ylfwdwgmpilzyaph”.
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Malware executing the third stage of WhisperGate
Stage 03
Here we have a 32-bit DLL, also developed in .NET. Since this file is directly loaded by the second stage as a
.NET assembly, the DLL doesn’t have an entry point, which requires some adjustments to make dynamic analysis
feasible.
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Binary information about WhisperGate’s third stage.
As shown in the image above, the file is protected with Eazfuscator, likely to hinder researchers’ analysis.
Searching throughout the decompiled code, we can find the same method that is executed by the second stage.
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Main function from the third stage of WhisperGate.
Once running, it checks if the process is running as an Administrator. If it’s not the case, it launches itself with
elevated permissions and exits the process.
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Malware checking for administrative permissions.
Then, it drops a VBS named “Nmddfrqqrbyjeygggda.vbs” into the Windows temporary folder, containing a
simple PowerShell code that adds the path “C:\” to Windows Defender’s exclusion list.
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Simple VBS / PowerShell to bypass Windows Defender.
It also drops an executable named “AdvancedRun.exe” to the same directory, which is a tool from NirSoft to
execute programs with different settings. WhisperGate uses this tool to execute commands in the
“TrustedInstaller” group context.
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Usage of AvancedRun tool, by NirSoft.
It executes two commands with this tool, both as an attempt to disable Windows Defender. The first one tries to
stop Defender’s service, and the second tries to delete its respective folder.
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Commands executed with AdvancedRun.
Then, WhisperGate copies “InstallUtil.exe” to Windows temporary folder, which is a binary from .NET
Framework.
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Copying InstallUtil executable to Windows temporary folder.
And finally, WhisperGate’s last stage is injected into an instance of the InstallUtil’s process. The payload is stored
within an encrypted resource, where all the bytes are reversed and compressed with Gzip.
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Malware loading WhisperGate’s last stage.
Stage 04
The binary used in this stage is quite similar to the first one in terms of compiler and linker.
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WhisperGate’s last stage.
Looking at the main function of the malware, we have two functions being called prior to the end of the execution.
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WhisperGate’s main function.
At the function we named “mw_main_routine”, the malware starts by listing the drives with the help of
GetLogicalDrives API.
Malware listing OS drives.
Then, it uses GetDriveTypeW to check if the drive is either fixed or remote. If that’s the case, it starts the function
that will wipe the files.
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Malware checking the drive type.
Within the function we named “mw_wipe_files”, it starts by listing all the files in the root path of the drive with
FindFirstFileW.
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Malware listing all the files in the current directory.
If the current object is a directory, the “mw_wipe_files” function is called recursively with the identified directory
as a parameter. This is verified by calling the “_wstat” function and checking the st_mode bits.
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Malware checking if the current object is a directory.
WhisperGate does not wipe files in the Windows directory.
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WhisperGate skipping Windows folder.
The last verification is related to the file’s extension, where the malware iterates over a list of targeted extensions
and, if the file name matches, a function we named “mw_write_bytes_to_file” is called.
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WhisperGate checking for targeted extensions.
WhisperGate targets many files with extensions related to websites, such as “.html”, “.php”, “.asp”, “.jsp”, as well
as common documents like “.doc”, “.xls”, “.ppt”, etc. A complete list of targeted extensions can be found in our
GitHub repository.
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WhisperGate’s targeted extensions.
And finally, if the file matches the criteria, WhisperGate wipes the file by replacing its content with a sequence of
0x100000 bytes of 0xCC.
WhisperGate wiping system’s files.
Also, a random extension is appended to the file’s name.
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Files wiped by WhisperGate.
Once it’s over, WhisperGate deletes itself through a simple command line, where “%s” is the file path obtained
with GetModuleFileNameA.
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This is the only behavior of WhisperGate’s last stage. Paying the ransom demanded would be fruitless because the
MBR and files were simply overwritten, not encrypted like they would be by ransomware. 
Conclusions
WhisperGate is a multi-stage destructive malware that has emerged in the midst of the geopolitical conflict that is
still unfolding in Ukraine. Netskope Threat Labs is on the lookout for any malware that may appear with an
apparent political motivation, especially ones that may disrupt essential services, such as infrastructure. It’s also
interesting to see this threat using Discord to host one of the payloads, showing again the preference of cloud apps
usage by cyber attackers. We echo CISA’s recommendations released in this note to implement cybersecurity
measures for critical infrastructure.
Protection
Netskope Threat Labs is actively monitoring this campaign and has ensured coverage for all known threat
indicators and payloads. 
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Netskope Threat Protection
Win32.Trojan.WhisperGate
Win32.Network.WhisperGate
ByteCode-MSIL.Trojan.WhisperGate
Netskope Advanced Threat Protection provides proactive coverage against this threat.
Gen.Malware.Detect.By.StHeur indicates a sample that was detected using static analysis
Gen.Malware.Detect.By.Sandbox indicates a sample that was detected by our cloud sandbox
IOCs
A full list of IOCs and Yara rules can be found in our GitHub repository.
Source: https://www.netskope.com/blog/netskope-threat-coverage-whispergate
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Binary information about WhisperGate’s second stage. 
Once running, it downloads the third stage from a Discord server, named “Tbopbh.jpg”.
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