ZKTeco Biometric SQL Injection
  • By manager
  • Last updated: June 15, 2024

ZKTeco Biometric SQL Injection

Critical Vulnerabilities Discovered in ZKTeco Hybrid Biometric Terminal: A Detailed Analysis

An analysis of ZKTeco‘s hybrid biometric access system has uncovered 24 critical security flaws, highlighting serious cyber security risks. Among these, a particularly alarming flaw allows for SQL injection via QR codes, raising significant concerns about the security of biometric access control systems, which are essential in high-security environments.

Overview of Biometric Terminals

Biometric terminals are advanced devices employed for personal identification and access control, relying on unique human physical characteristics such as fingerprints, facial features, voice, or iris patterns to verify identity. These terminals are commonly used in sensitive areas like server rooms, executive offices, and hazardous facilities, including nuclear power plants and chemical plants. They also record employees’ work hours, enhancing productivity and reducing fraud.

Advantages and Disadvantages of Biometric Terminals


  • Highly Accurate Identification: Biometric data is unique to each individual, making it a reliable verification method.
  • Security: Biometric data is difficult to forge or copy, enhancing system security.
  • User-Friendly: Users do not need to remember passwords or carry access cards.
  • Efficiency: These terminals can quickly process large amounts of data, reducing wait times.


  • Cost: Biometric terminals are generally more expensive than traditional access control systems.
  • Risk of Error: Systems can misidentify individuals with damaged fingertips or other anomalies.
  • Privacy Concerns: There are concerns about biometric data being stored and used without consent.
  • Technological Limitations: Some methods, like facial recognition, can be less effective in low light or when the subject is wearing a mask.

Security Analysis of ZKTeco Terminal

The ZKTeco hybrid biometric terminal supports multiple authentication methods, including facial recognition, passwords, electronic passes, and QR codes. The device features several physical interfaces such as RJ45, RS232, and RS485, and can be connected to other scanners or authentication methods.

Discovered Vulnerabilities

The security analysis revealed several critical vulnerabilities:

  • QR Code SQL Injection: The device is susceptible to SQL injection attacks via QR codes. Attackers can gain unauthorized access by presenting a QR code containing malicious SQL code.
  • Buffer Overflow: Multiple buffer overflow vulnerabilities were identified due to improper user input handling.
  • Unencrypted Firmware: The firmware was found to be unencrypted, making it easier for attackers to extract and analyze.
  • Weak Authentication: The device’s authentication mechanism is weak, with the default password set to ‘0’ and easily brute-forced.

Exploitation and Impact

The discovered vulnerabilities could allow attackers to:

  • Bypass Authentication: Gain unauthorized physical access to secure areas.
  • Leak Biometric Data: Extract sensitive biometric data from the device.
  • Network Access: Gain network access to the device and use it as a pivot point for further attacks.


The discovery of these vulnerabilities in a widely used biometric terminal underscores the critical need for rigorous security measures in the design and deployment of biometric systems. While biometric terminals offer significant benefits in terms of security and efficiency, they also introduce new risks that must be carefully managed. Organizations using such devices should ensure they are correctly configured and regularly updated to mitigate potential security threats.


Organizations should:

  • Conduct regular security audits and vulnerability assessments.
  • Ensure firmware is encrypted and up-to-date.
  • Implement strong authentication mechanisms.
  • Educate staff on the importance of security best practices.

By taking these steps, organizations can better protect their biometric systems and the sensitive data they manage. In conclusion, the discovery of 24 critical vulnerabilities in ZKTeco’s hybrid biometric access system underscores significant cyber security challenges. These flaws, ranging from SQL injections to command injections and buffer overflows, highlight the potential for severe exploitation, including unauthorized access and data theft. The findings emphasize the urgent need for robust cyber security measures to safeguard biometric data and ensure the integrity of access systems, reinforcing the importance of continuous vulnerability assessment and timely remediation in maintaining secure cyber environments.