The decision to update the did not happen in a vacuum. It was driven by three major factors:
Ensure the changes are committed to the non-volatile flash memory storage so they persist after a reboot: sync Use code with caution.
| Device Age / Firmware | Telnet Username | Default Password | |----------------------|----------------|------------------| | Pre-2024 (old firmware) | root | zmm220 (or blank) | | Post-update (v2.3.1+) | admin | Printed on device label (12-character alphanumeric) | zmm220 default telnet password updated
More recently, CVE-2024-13966 was identified in ZKTeco BioTime software, allowing unauthenticated attackers to enumerate usernames and log in as any user whose password remains unchanged from the default value . While this primarily affects the BioTime software platform, it underscores the broader organizational risk of relying on unchanged default credentials.
Telnet transmits data, including authentication credentials, in plaintext. Anyone monitoring network traffic can capture passwords using basic packet sniffing tools. The decision to update the did not happen in a vacuum
ZMM220 is a high-performance hardware platform developed by ZKTeco (now known as ) for biometric attendance machines, access control terminals, and related security devices. The platform typically runs Linux on a MIPS architecture with kernel version 3.0.8, representing a significant upgrade in processing capabilities with a 1.0 GHz to 1.2 GHz CPU, compared to older platforms like ZEM600 and ZEM800.
After applying updates, perform a vulnerability scan to ensure compliance: While this primarily affects the BioTime software platform,
Bad actors can upload malicious binaries, turn the terminal into a network botnet node, or modify system logs to erase evidence of unauthorized entry. Step-by-Step Guide: Updating the ZMM220 Telnet Password
: Place all ZMM220-powered access control terminals on a dedicated, isolated Virtual Local Area Network (VLAN).