Malware Analysis Report

2025-05-05 22:14

Sample ID 250416-xd8nkstzdy
Target linux_amd64.elf
SHA256 c09b6758cad544622f1a8a0e5edb64af4b952eb95ae94dcfe20fc1af2a9ab7e4
Tags
kaiji defense_evasion discovery execution persistence privilege_escalation
score
10/10

Table of Contents

Analysis Overview

MITRE ATT&CK

Enterprise Matrix V16

Analysis: static1

Detonation Overview

Signatures

Analysis: behavioral1

Detonation Overview

Command Line

Signatures

Processes

Network

Files

Analysis Overview

score
10/10

SHA256

c09b6758cad544622f1a8a0e5edb64af4b952eb95ae94dcfe20fc1af2a9ab7e4

Threat Level: Known bad

The file linux_amd64.elf was found to be: Known bad.

Malicious Activity Summary

kaiji defense_evasion discovery execution persistence privilege_escalation

Kaiji

Kaiji family

Modifies Watchdog functionality

Executes dropped EXE

Modifies systemd

Write file to user bin folder

Modifies init.d

Creates/modifies Cron job

Creates/modifies environment variables

Enumerates running processes

Modifies Bash startup script

Changes its process name

Command and Scripting Interpreter: Unix Shell

Enumerates kernel/hardware configuration

Reads runtime system information

MITRE ATT&CK

Analysis: static1

Detonation Overview

Reported

2025-04-16 18:45

Signatures

Kaiji

Description Indicator Process Target
N/A N/A N/A N/A

Kaiji family

kaiji

Analysis: behavioral1

Detonation Overview

Submitted

2025-04-16 18:45

Reported

2025-04-16 18:47

Platform

ubuntu2204-amd64-20250410-en

Max time kernel

148s

Max time network

147s

Command Line

[/tmp/linux_amd64.elf]

Signatures

Kaiji

Description Indicator Process Target
N/A N/A N/A N/A

Kaiji family

kaiji

Executes dropped EXE

Description Indicator Process Target
N/A /etc/32676 /bin/sh N/A

Modifies Watchdog functionality

defense_evasion
Description Indicator Process Target
File opened for modification /dev/watchdog /tmp/linux_amd64.elf N/A
File opened for modification /dev/misc/watchdog /tmp/linux_amd64.elf N/A

Creates/modifies Cron job

execution persistence privilege_escalation
Description Indicator Process Target
File opened for modification /etc/crontab /bin/sh N/A

Creates/modifies environment variables

persistence privilege_escalation defense_evasion
Description Indicator Process Target
File opened for modification /etc/profile.d/bash_cfg /tmp/linux_amd64.elf N/A
File opened for modification /etc/profile.d/bash_cfg.sh /tmp/linux_amd64.elf N/A
File opened for modification /etc/profile.d/gateway.sh /tmp/linux_amd64.elf N/A

Enumerates running processes

Modifies init.d

persistence
Description Indicator Process Target
File opened for modification /etc/init.d/plymouth /tmp/linux_amd64.elf N/A
File opened for modification /etc/init.d/anacron /tmp/linux_amd64.elf N/A
File opened for modification /etc/init.d/apparmor /tmp/linux_amd64.elf N/A
File opened for modification /etc/init.d/kmod /tmp/linux_amd64.elf N/A
File opened for modification /etc/init.d/cryptdisks /tmp/linux_amd64.elf N/A
File opened for modification /etc/init.d/hwclock.sh /tmp/linux_amd64.elf N/A
File opened for modification /etc/init.d/lvm2-lvmpolld /tmp/linux_amd64.elf N/A
File opened for modification /etc/init.d/sssd /tmp/linux_amd64.elf N/A
File opened for modification /etc/init.d/acpid /tmp/linux_amd64.elf N/A
File opened for modification /etc/init.d/alsa-utils /tmp/linux_amd64.elf N/A
File opened for modification /etc/init.d/iscsid /tmp/linux_amd64.elf N/A
File opened for modification /etc/init.d/open-iscsi /tmp/linux_amd64.elf N/A
File opened for modification /etc/init.d/procps /tmp/linux_amd64.elf N/A
File opened for modification /etc/init.d/ssh /tmp/linux_amd64.elf N/A
File opened for modification /etc/init.d/unattended-upgrades /tmp/linux_amd64.elf N/A
File opened for modification /etc/init.d/apport /tmp/linux_amd64.elf N/A
File opened for modification /etc/init.d/bluetooth /tmp/linux_amd64.elf N/A
File opened for modification /etc/init.d/cryptdisks-early /tmp/linux_amd64.elf N/A
File opened for modification /etc/init.d/cups-browsed /tmp/linux_amd64.elf N/A
File opened for modification /etc/init.d/udev /tmp/linux_amd64.elf N/A
File opened for modification /etc/init.d/avahi-daemon /tmp/linux_amd64.elf N/A
File opened for modification /etc/init.d/keyboard-setup.sh /tmp/linux_amd64.elf N/A
File opened for modification /etc/init.d/rsync /tmp/linux_amd64.elf N/A
File opened for modification /etc/init.d/x11-common /tmp/linux_amd64.elf N/A
File opened for modification /etc/init.d/cron /tmp/linux_amd64.elf N/A
File opened for modification /etc/init.d/plymouth-log /tmp/linux_amd64.elf N/A
File opened for modification /etc/init.d/spice-vdagent /tmp/linux_amd64.elf N/A
File opened for modification /etc/init.d/console-setup.sh /tmp/linux_amd64.elf N/A
File opened for modification /etc/init.d/dbus /tmp/linux_amd64.elf N/A
File opened for modification /etc/init.d/saned /tmp/linux_amd64.elf N/A
File opened for modification /etc/init.d/cups /tmp/linux_amd64.elf N/A
File opened for modification /etc/init.d/gdm3 /tmp/linux_amd64.elf N/A
File opened for modification /etc/init.d/openvpn /tmp/linux_amd64.elf N/A

Modifies systemd

persistence privilege_escalation
Description Indicator Process Target
File opened for modification /usr/lib/systemd/system/quotaoff.service /tmp/linux_amd64.elf N/A

Write file to user bin folder

persistence
Description Indicator Process Target
File opened for modification /usr/bin/include/ps /tmp/linux_amd64.elf N/A
File opened for modification /usr/bin/include/ss /tmp/linux_amd64.elf N/A
File opened for modification /usr/bin/include/ls /tmp/linux_amd64.elf N/A
File opened for modification /usr/bin/include/find /tmp/linux_amd64.elf N/A
File opened for modification /usr/bin/dir /tmp/linux_amd64.elf N/A
File opened for modification /usr/bin/include/dir /tmp/linux_amd64.elf N/A
File opened for modification /usr/bin/include/lsof /tmp/linux_amd64.elf N/A
File opened for modification /usr/bin/ps /tmp/linux_amd64.elf N/A
File opened for modification /usr/bin/ss /tmp/linux_amd64.elf N/A
File opened for modification /usr/bin/ls /tmp/linux_amd64.elf N/A
File opened for modification /usr/bin/find /tmp/linux_amd64.elf N/A
File opened for modification /usr/bin/lsof /tmp/linux_amd64.elf N/A

Modifies Bash startup script

persistence
Description Indicator Process Target
File opened for modification /etc/profile.d/bash_cfg /tmp/linux_amd64.elf N/A
File opened for modification /etc/profile.d/bash_cfg.sh /tmp/linux_amd64.elf N/A
File opened for modification /etc/profile.d/gateway.sh /tmp/linux_amd64.elf N/A

Changes its process name

Description Indicator Process Target
Changes the process name, possibly in an attempt to hide itself ksoftirqd/0 /tmp/linux_amd64.elf N/A

Command and Scripting Interpreter: Unix Shell

execution
Description Indicator Process Target
N/A N/A /bin/sh N/A
N/A N/A /bin/sh N/A
N/A N/A /bin/sh N/A
N/A N/A /bin/sh N/A

Enumerates kernel/hardware configuration

discovery
Description Indicator Process Target
File opened for reading /sys/kernel/mm/transparent_hugepage/hpage_pmd_size /tmp/linux_amd64.elf N/A
File opened for reading /sys/kernel/mm/transparent_hugepage/hpage_pmd_size /tmp/linux_amd64.elf N/A

Reads runtime system information

discovery
Description Indicator Process Target
File opened for reading /proc/1737/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/556/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/1587/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/774/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/1080/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/1178/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/1220/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/filesystems /usr/bin/systemctl N/A
File opened for reading /proc/680/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/799/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/1381/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/1199/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/788/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/1097/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/1228/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/filesystems /usr/bin/systemctl N/A
File opened for reading /proc/666/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/973/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/1032/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/1096/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/413/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/915/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/1094/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/1512/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/filesystems /usr/bin/systemctl N/A
File opened for reading /proc/415/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/803/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/890/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/1492/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/989/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/1574/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/1332/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/filesystems /usr/bin/mount N/A
File opened for reading /proc/636/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/1101/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/1104/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/1581/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/377/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/522/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/641/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/1455/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/426/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/686/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/1018/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/1108/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/filesystems /usr/bin/systemctl N/A
File opened for reading /proc/634/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/927/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/1092/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/1125/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/1435/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/1203/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/1214/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/948/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/979/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/1127/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/filesystems /usr/bin/sed N/A
File opened for reading /proc/1249/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/586/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/1442/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/1722/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/907/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/315/stat /tmp/linux_amd64.elf N/A
File opened for reading /proc/594/stat /tmp/linux_amd64.elf N/A

Processes

/tmp/linux_amd64.elf

[/tmp/linux_amd64.elf]

/tmp/linux_amd64.elf

[/tmp/linux_amd64.elf ]

/bin/sh

[/bin/sh -c /etc/32676&]

/etc/32676

[/etc/32676]

/usr/sbin/service

[service crond start]

/usr/bin/basename

[basename /usr/sbin/service]

/usr/bin/sleep

[sleep 60]

/usr/bin/basename

[basename /usr/sbin/service]

/usr/bin/sed

[sed -ne s/\.socket\s*[a-z]*\s*$/.socket/p]

/usr/bin/systemctl

[systemctl list-unit-files --full --type=socket]

/usr/local/sbin/systemctl

[systemctl start crond.service]

/usr/local/bin/systemctl

[systemctl start crond.service]

/usr/sbin/systemctl

[systemctl start crond.service]

/usr/bin/systemctl

[systemctl start crond.service]

/bin/sh

[/bin/sh -c cd /boot;systemctl daemon-reload;systemctl enable quotaoff.service;systemctl start quotaoff.service;journalctl -xe --no-pager]

/usr/bin/systemctl

[systemctl daemon-reload]

/usr/bin/systemctl

[systemctl enable quotaoff.service]

/usr/bin/systemctl

[systemctl start quotaoff.service]

/usr/bin/journalctl

[journalctl -xe --no-pager]

/bin/sh

[/bin/sh -c cd /boot;ausearch -c 'System.mod' --raw | audit2allow -M my-Systemmod;semodule -X 300 -i my-Systemmod.pp]

/bin/sh

[/bin/sh -c echo "*/1 * * * * root /.mod " >> /etc/crontab]

/usr/bin/renice

[renice -20 1574]

/usr/bin/mount

[mount -o bind /tmp/ /proc/1574]

/usr/sbin/service

[service cron start]

/usr/bin/basename

[basename /usr/sbin/service]

/usr/bin/basename

[basename /usr/sbin/service]

/usr/bin/sed

[sed -ne s/\.socket\s*[a-z]*\s*$/.socket/p]

/usr/bin/systemctl

[systemctl list-unit-files --full --type=socket]

/usr/local/sbin/systemctl

[systemctl start cron.service]

/usr/local/bin/systemctl

[systemctl start cron.service]

/usr/sbin/systemctl

[systemctl start cron.service]

/usr/bin/systemctl

[systemctl start cron.service]

/usr/bin/systemctl

[systemctl start crond.service]

/usr/bin/sleep

[sleep 60]

/usr/bin/sleep

[sleep 60]

Network

Country Destination Domain Proto
N/A 224.0.0.251:5353 udp
US 8.8.8.8:53 www.google.com udp
US 8.8.8.8:53 www.google.com udp
US 154.40.47.248:888 tcp

Files

/etc/.walk

MD5 8f30fc5c9bc57e29f60a3bbc55233340
SHA1 cd71c7c3d63ddb4ece0a11590a5c99b7139bcbbf
SHA256 87bb285fc080a6373ed6c0797993e459411392778563b1ca1ed9d8edb7bf3a35
SHA512 73b3ecc8df6140d7b1fbaa8b73010484fe765161c3b46c7efad5606d60677431f5a7896b314e6db0517390bd7e957658d5ad44c4a68c5cd6696213bda41871fe

/etc/.walk

MD5 508d9067c51abc99613135a58cf4c9f2
SHA1 da531b9d4223e33e82274e56d065dc25a12de4fd
SHA256 e65efc23357df0b10d2a985f42334b19626499bb6b5c0aa5e252359525cb1278
SHA512 023fef9023a4f7387a5b528bdd873c3ec84a4fd85a2f6bd5a16af4324449d0a533e973e4036dc5d4f20f8e8635cd93cf525aa06a2187cc0eaedc18208526e5e2

/etc/32676

MD5 585f408444cbca746945f0cb63f2c3f0
SHA1 0e44bae17174f04514e770ca7fc4bec1007e39cd
SHA256 ebb961c647363dfa90f302de378e0e61807b9b792fc86616635a713cca8f4299
SHA512 022241dbafad55164701f67ef5b84154e3af97c5dfe77dee7bf8406f2befbd2962bbf4f243432b2f41d6c2376b87fcf551fd6945e03ddb02a5619c2f0f69c596

/boot/System.mod

MD5 4a67fbaac9ab2555654663e56ad125a1
SHA1 d6dbe82c06c8bd5b83eea3daa26605b10c4e4457
SHA256 c09b6758cad544622f1a8a0e5edb64af4b952eb95ae94dcfe20fc1af2a9ab7e4
SHA512 7a88709312bfdf50b3900abeab5e916fcbb63e773b58e158b557f239d1e8b861c4294dd86cfec80e4baf199fcb606d484da991c7b42594ec8999f945a4afb154

/usr/lib/systemd/system/quotaoff.service

MD5 b02de6cd28cd922b18d9d93375a70d8b
SHA1 021426a5a2ff9edc80ba5936c94b37525538885e
SHA256 d8d8e5cd33aa3450cd74c63716a02f3dff39efef2836559f110bc93663b1380a
SHA512 db3fe03ad5e599e6c03aaec7bf1242f5509fbb624adb9afb7499e25487daef3f3f1c6babf51570b527a5ac5c9f4b079ae4cc53baa9497c0a121328bef8d04422

/.mod

MD5 f5a3713282e43c200f30342f5ff5e2ea
SHA1 2b2ce1a207e2b691a074c6f78f71c4785aae426a
SHA256 6ab64e727571458d4884fb2fe82c27c467db0699cb8f648b3f0217c35d2b7511
SHA512 5bcb8cd360409147a486755f90e0cdd97183af02ce8de5135b7c6a8a010deb9ef12dcd5ee9a2a8fd2e159347f68e72d6b7fd75e943b4fcd928d7a74b97476013

/etc/profile.d/gateway.sh

MD5 227a551a2ad43e9a81c45248e53cb23f
SHA1 a29d7440a50030bb93310486f52972b3ffac2eed
SHA256 590f1470687fe8cedf2b4a702258987fc4fdd82f71f570dadcf9728553f30018
SHA512 9e5fd551602461d6b2626a3f9258934aca273ed13e53d51e72bcfc1a446bcc7bd44cfcbe6b670bef760c06dbdbfef6261046cd01ec1c9e669d1c7251b789ccff