Hikvision IP Camera & NVR Web Server Remote Command Injection Vulnerability (CVE-2021-36260) Security Advisory
Executive & SecOps Summary
SECOPS ASSESSMENTWeb server software embedded in various Hikvision IP cameras and Network Video Recorders (NVRs)
Unauthenticated remote attackers can execute arbitrary system commands with root privileges by sending specially crafted HTTP requests, leading to full device compromise
Immediately upgrade to the latest patched firmware version provided by the vendor and restrict direct internet access to the devices
Affected Products & Version Scope
Remediation & Live Workaround Commands
PATCH & WORKAROUND1. Official Patch & Version Upgrade Commands
Download the appropriate patched firmware version for your specific device model from the official Hikvision support portal. The firmware can be updated via the web GUI or using a TFTP server. Below is an example of setting up a TFTP server on Linux to host the firmware file (digicap.dav) for device recovery or upgrade:
# 1. Install and enable TFTP server on Debian/Ubuntu
sudo apt-get update && sudo apt-get install tftpd-hpa -y
# 2. Copy the official patched firmware (digicap.dav) to the TFTP directory
sudo cp ./digicap.dav /srv/tftp/
sudo systemctl restart tftpd-hpa
# 3. Verify TFTP service status
sudo systemctl status tftpd-hpa --no-pager2. Temporary Workaround & Hardening Configuration
If immediate patching is not feasible, isolate the vulnerable devices from the public internet. Use firewall rules to restrict access to the web management ports (TCP 80, 443) only to trusted administrative networks. Below is an example of configuring iptables to restrict access:
# 1. Drop all incoming HTTP/HTTPS traffic to the camera by default
sudo iptables -A INPUT -p tcp --dport 80 -j DROP
sudo iptables -A INPUT -p tcp --dport 443 -j DROP
# 2. Insert a rule at the top to allow access only from a trusted admin subnet (e.g., 192.168.10.0/24)
sudo iptables -I INPUT 1 -p tcp -s 192.168.10.0/24 --dport 80 -j ACCEPT
sudo iptables -I INPUT 2 -p tcp -s 192.168.10.0/24 --dport 443 -j ACCEPT
# 3. Save the iptables rules
sudo iptables-save | sudo tee /etc/iptables/rules.v43. Log Audit & IoC Verification Commands
Inspect the web server access logs for suspicious patterns, such as shell commands or metacharacters embedded in HTTP requests. Use the following script to scan log files for potential exploitation attempts:
#!/bin/bash
# Define the path to the web server logs
LOG_PATH='/var/log/nginx'
echo '[+] Scanning logs for CVE-2021-36260 exploitation attempts...'
# Search for common command injection indicators in the logs
egrep -i '(sh|bash|cmd|ping|wget|curl|tftp|chmod|/bin/)' ${LOG_PATH}/*.log 2>/dev/null
if [ $? -eq 0 ]; then
echo '[!] WARNING: Suspicious command injection patterns detected in logs. Immediate investigation required.'
else
echo '[+] No suspicious patterns found.'
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Technical Root Cause & Exploitation Mechanics
1. Vulnerability Overview & Root Cause
This vulnerability (CVE-2021-36260) is a critical command injection flaw residing in the web server module of Hikvision IP cameras and NVR devices. The root cause is insufficient input validation of user-supplied data (specifically within XML payloads of certain API endpoints) before passing it to system command execution functions. This allows remote attackers to bypass authentication entirely and execute arbitrary operating system commands on the underlying Linux system.
2. Exploitation Mechanics & Attack Scenario
An attacker exploits this vulnerability by sending a malicious HTTP PUT or POST request containing a crafted XML payload to the device's web management port (typically TCP 80 or 443). The vulnerable endpoint fails to sanitize shell metacharacters (such as ';', '|', or '`') within the input fields. Consequently, the web server executes the injected commands with the privileges of the web server process, which typically runs as 'root'. Since no authentication is required, the exploit can be executed reliably from any network location that can reach the device.
3. Infrastructure & Business Impact
With a CVSS score of 9.8 (Critical), this vulnerability is highly severe and is actively exploited in the wild, as confirmed by its inclusion in the CISA KEV catalog. Successful exploitation allows attackers to gain full control of the surveillance equipment, enabling unauthorized video monitoring, data exfiltration, and privacy breaches. Furthermore, compromised devices are frequently recruited into IoT botnets (such as Mirai variants) or used as pivot points to launch lateral movement attacks against internal corporate networks.
Official Vendor Advisories & References
A command injection vulnerability in the web server of some Hikvision product. Due to the insufficient input validation, attacker can exploit the vulnerability to launch a command injection attack by sending some messages with malicious commands.
Frequently Asked SecOps Questions (CVE-2021-36260)
FAQQ1. How critical is CVE-2021-36260 and is it actively exploited in the wild?
CVE-2021-36260 is rated CVSS 9.8 (CRITICAL) with a 30-day EPSS exploitation probability of 99.9%. It is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, requiring immediate emergency remediation.
Q2. Which vendors and products are affected by CVE-2021-36260?
Primary impacted vendors include hikvision across ip camera, network video recorder, web server. Scope summary: Multiple Hikvision IP cameras, dome cameras, and NVR models running firmware versions built prior to June 2021 (refer to the official Hikvision advisory for the complete list of affected models)
Q3. What temporary mitigations or workarounds exist for CVE-2021-36260 before patching?
[Mitigation] Immediately upgrade to the latest patched firmware version provided by the vendor and restrict direct internet access to the devices Follow the CLI remediation commands and interactive SecOps checklist on this page to restrict exposure prior to your maintenance window.
Generate an Internal Engineering Notice or CISO Report for CVE-2021-36260
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